Ostenisbly, amplifiers with a switching output stage - encompasses digital and anlog input stages, regardless of linear comparator for pulse variation (thanks, John for the description)

Commonly known as digital amplifiers.

in a companion to the Digital HT receivers list, I think it may be a good time to start this thread. For those who are looking for more power and a higher end implementation of the (relatively) new technologies

How does a PWM amplifer work? PS Audio explains (http://www.psaudio.com/ps/knowledge/how-does-a-class-d-digital-amplifier-work/)

Acoustic Reality http://www.acoustic-reality.com/
eAR202, etc (ICEPower)

Aivin http://www.aivin.com.cn/
DT300 (http://www.aivin.com.cn/files/english/products/proweb/DT300.htm) (Tripath)

Analog Research Technology http://www.analogresearch-technology.com/

Arion Audio http://www.arionaudio.com
MK1000 (http://www.analysisaudio.com/Avmentor.htm) (proprietary)

AudioArt (NL) http://www.audioart.nl/
Van Medevoort MA240 (Hypex UcD)

Audiodigit http://www.audiodigit.com/
MC 8x100 (Tripath)

AudioResearch http://www.audioresearch.com/
150.2, 300.2, 150M (Tripath)

AV123
X-Empower, xAmp (prelaunch (http://av123forum.com/showthread.php?threadid=10683))
(Philips class-D?)

Axiom Audio http://www.axiomaudio.com/
A1400-8 (http://www.axiomaudio.com/a1400-8.html) (ICEPower)

B&O http://www.icepower.bang-olufsen.com/
(ICEPower)

BelCanto http://www.belcantodesign.com/products.html
Evo (Tripath) eOne (ICEPower)

Bertram http://www.audiokabel.dk/eng-main.htm
(ICEPower)

Blacknote http://www.blacknote.eu/
DSA 100, DSA 150 http://www.blacknote.eu/products/dsa.php

Bryston http://www.bryston.ca/
D250Z multichannel power amp

Carver http://www.carverusa.com/
300.2, 700.2, 1200.2

Cary Audio http://www.caryaudio.com/
A 306 power amplifier (http://www.caryaudio.com/products/designer/a306.html)

Channel Islands Audio http://www.ciaudio.com/
D100, D200 (Hypex UcD)

Chapter Audio http://www.chapteraudio.co.uk/
Couplet Power Amp (proprietary WMP class-D)

D-Sonic http://www.d-sonic.net/
Magnum (http://www.d-sonic.net/) (ICEPower)

Devialet http://www.devialet.com/
D-Premier (http://www.devialet.com/overview.php) (Hybrid, proprietary)

DIYCable http://www.diycable.com/
Exodus (http://www.diycable.com/main/default.php?cPath=140) (Hypex UcD)

Egosys http://www.egosys.co.jp/
Audiotrak DrAMP (http://www.audiotrak.net/drAMP.htm) (Tripath)

Elan http://www.elanhomesystems.com/
D1200, D1600 (12 and 16 channel power amps, Tripath)

Electronic Visionary Systems http://www.tweakaudio.com/
EVS-2 (http://www.tweakaudio.com/EVS-2/Amp_page.html) (ICEPower)

Flying Mole http://www.flyingmoleelectronics.com/
(proprietary class-D)

Genesis http://www.genesisloudspeakers.com
Genesis Reference GR180 (Hypex)

Gilmore Audio http://www.glacieraudio.com/
Raven, Raptor, Dragonfly (http://www.glacieraudio.com/new%20Glacier%20Audio%20Site/Products%20folder/Gilmore/Gilmore-amps.htm) m/ch (looks like ICE)

H2O Audio http://www.iceh2oaudio.com/
M250, M500 (ICEpower)

Halcro http://www.halcro.com/logic/home.asp
Lyrus

Huygens Audio http://www.huygensaudio.com/
MCD-1202, MCD-1802 (MHz Class-D (http://www.class-d.net/))

Integra /Onkyo http://www.integrahometheater.com/
DTA 9.4 (http://www.integrahometheater.com/model.cfm?class=Separates&m=DTA-9.4&p=i) 7x120W 8Ω

Jeff Rowland http://www.jeffrowland.com/
Model 501 (ICEPower)

Jjaz Audio http://www.jjaz.dk/
(ICEPower)

Kharma http://www.kharma.com/
MP150 (http://www.kharma.com/frame.htm?products/matrix/mp150.htm)

LC Audio http://www.lcaudio.com/
Predator SE (http://www.lcaudio.com/index.php?page=37) (ZapPulse)

Marantz http://www.marantz.jp
Opsodis ES-150 (http://www.marantz.jp/ce/products/hometheater/opsodis/es150/index.html) (D2Audio) 2ch virtual surround

Medius [DK] http://www.medius.cc/
A II, A III (http://www.medius.cc/index2.asp?target=products&subtarget=amplifiers&view=amplifiers)

Meridian http://www.meridian-audio.com
G95 DVD receiver (http://www.meridian-audio.com/p_g95.htm) system (Hypex UcD)

MG Audiolabs http://www.mglaudiolabs.com/
Symphony (http://www.mglaudiolabs.com/products/symphony.htm) (Hypex UcD)

Midgard Audio http://www.midgardaudio.no/www/
(ICEPower)

MindCraft (NL) http://www.mindcraft.nl/
Media Amp One (http://www.mindcraft.nl/mediaampone.htm) (Hypex UcD)

Murano-Audio (TW) http://www.murano-audio.com/
P500, P1000 (ICEPower)

NAD http://nadelectronics.com/ NEW
M2 Direct Digital (http://nadelectronics.com/products/masters-series/M2-Direct-Digital-Amplifier) (Zetex)

NHT http://nhthifi.com/
Power2 (http://nhthifi.com/2006/products/s/power2.html), Power5 (http://nhthifi.com/2006/products/s/power5.html) (ICEpower)

Nuforce http://www.nuforce.com/
Ref 8, Ref 8b, Ref 9 (nPhysics proprietary class-D)

NuVo Technologies http://www.nuvotechnologies.com/
NV-P2100 (http://www.nuvotechnologies.com/prozone/nv_p2100.htm)

Onkyo http://www.onkyo.com/
A-1VL, A-9755, A-9555 (http://www.eu.onkyo.com/indices/index_com_en_53538.html) (Proprietary)

Primare http://www.primare.net/
CDI10 (http://www.primare.net/00002/00192/00193/) (Proprietary Ultra Fast Power Device (UFPD))

PSAudio http://www.psaudio.com/
GCA, GCMC, Trio A100 (ICEPower)

Red Dragon Audio http://www.reddragonaudio.com/
(ICEpower)

RedWineAudio http://www.redwineaudio.com/
Clari-T, Lotus (Tripath)

Rotel http://www.rotel.com/
1077 (7x100), 1092 (2x500) (ICEPower)

Seymour AV http://www.seymourav.com/amps.asp
Ice Block Amps (Ice Power)

Sharp http://www.sharpusa.com/
SM-SX1, SM-SX100

Sonneteer http://freespace.virgin.net/sonneteer.audio/bronte.html
Brontë (Tripath)

Sony http://www.sony.com/
TA-DA9000ES, TA-FA1200ES (http://www.stoneaudio.co.uk/stoneaudio/products/details.asp?product=2439) (S-Master)

Spectron http://www.spectronav.com/
Musician, Troubador (int amp w digital inputs)

TactAudio/Lyngford http://www.tactaudio.dk/ http://www.lyngford.com/
Millennium & others (Equibit)

TEAC Esoteric http://teac.co.jp/av/esoteric/
AZ-1 pre-main (translated (http://babel.altavista.com/babelfish/trurl_pagecontent?lp=ja_en&trurl=http%3a%2f%2fwww.teac.co.jp%2fav%2fesoteric%2fsz1_uz1_ az1%2findex.html)), AI-10 (http://esoteric.teac.com/amplifiers_&_preamps/ai-10/) (Texas Instruments)

ThetaDigital http://www.thetadigital.com/
Virtu PowerDAC (http://www.thetadigital.com/press-release/virtu-09-06.htm) (Zetex class-Z)

UniwaveTek http://www.uniwavetek.com/
Anaco II

Wyred4Sound http://www.wyred4sound.com/
STI-500, STI-1000 (ICEpower)

Virtue Audio http://store.virtueaudio.com/
One.2, Two.2, Sensation M451, Sensation M901 (Tripath)
ICEBlock M5001 (ICEpower)

Yamaha http://www.yamaha.com/
MX-D1


I'm sure you all have more information and companies.

Hey SC,

It was my intension to do this at the "Paradigm Shift". I was just waiting for the "weather" to change there a bit before I do so but thanks for the post :D.


...

Looks good... except some do have an analog output stage but PWM in design and nature.


...

Hey SC,

It was my intension to do this at the "Paradigm Shift". I was just waiting for the "weather" to change there a bit before I do so but thanks for the post :D.


...

sorry I pre-empted you! heh heh :D

I hope won't be able to maintain a alphabetically sorted list for much longer though (cuz I'd have to include all the audio companies and new ones to boot)

That's cool, no biggy.




...

feel free to add stuff, and i will try update the first post :)

B&O...






...

http://www.stereotimes.com/MWC0511043.shtm

check out how many of the Hall of Fame winners for 2004 are erm, digital.

Dang! SC, great find... now I won't be able to sleep. :D

Did you see them speaker cables?.... :D :D :D


...

GED speaker cables on where? wasn't looking... but I will now

I think Theta Digital are er, digital :)

http://www.thetadigital.com/product/dreadnaught2/prod-info.htm

using this Zetex (http://www.zetex.co.uk/) ZXCW8100 chip (download specs (http://www.zetex.co.uk/3.0/pdf/ZXCW8100.pdf), PDF)

Page 2...

SILVERSMITH PALLADIUM INTERCONNECTS and SPEAKER WIRE -- 6FT - $10 grand :D:D:D

Look at the smile on that guy's face.



...

if i could sell a couple of lengths every so often, I'd be smiling too! LOL

There are a few bones to pick here.

The use of "Digital" is a misnomer. Class D, or "switching output stage" is a much more accurate description of this type of amplifier. Until you have a digital signal directly feeding the amplifier stage, it isn't a digital amplifier. There are a few that can rightly be called a digital amplifier, including the Tact, Sharp and the Spectron with digital input but that's about it.

Theta Digital's Dreadnaught II with 275w of idle power consumption for 5 channels (55w/channel) cannot be a switching output stage power amplifier. They did announce an amplifier at CEDIA with a switching output stage, but I don't know the model. It isn't the Dreadnaught II, which is a traditional class A/B amplifier.

I do not like the use of the term digital applied loosely. It's not that I don't like switching output stage amplifiers (I do), but rather that I prefer being accurate in our use of terminology :)

Best,

John,

point taken, thanks. I'll take any suggestion as to what to lump these under

(non~analog?)

Interesting and good point John.

While "Digital" is a misnomer for most, "Class-D" or "Switching output stage" in general are not accurate terminology for them as well in general. One thing that they all do have in common is the use of PWM in their circuit. The use of PWM is something you won't find in the "analog" classes of amplifier.

PWM and Class-D amps also goes hand-in-hand by description (see Wikipedia). Often they are refered to as one. In reality, it is true that Class-D is a PWM amp but not necessarily true the other way around.

Maybe "Analog" too is a misnomer as "some" of these amp brand theirs as such. It seems that this is due to the fact that in the current amp world such terms or branding as Digital, Class-D, PWM is somewhat of a turn-off. Wether it is misinformation or lack thereof, maybe it is bad publicity or lack of exposure we just don't know. Confusion has run-amock in the CE world.

What shall we call these "Digi-Amps" (as I have labeled them)? I think that question is best answered by the proper authorities. For the meantime, I will refer to them as Digital or Digi-Amps.


PS: Your welcome to coin a cool name for it that I may be inclined to use. :)


...

OK, I've seen this in a lot of threads now... maybe time for new terminology. My proposal:

If the output stage is not used in a linear way but the transistors "pulse" into an output coil, call them "Pulsing" amps.

If the input is analog it's an analog pulsing amplifier.

If the input is digital it's a digital pulsing amplifier.

If there is a digital conversion (PCM>PWM or DSD>PWM) call it a direct digital pulsing amplifier.

Hmm... I should take a patent on this :D

But seriously, it's an easy to remember pretty much sums up how the thing works? I'm changing my signature to match this proposal, lol :cool: - there's till things not explained in these words of course... but your can't put everything in there. For example, fixed frequency or self-oscillating comparator designs.

Yves

good suggestion - though pulse doesn't exactly describe the on-off state. or does it?

no one for my suggestion in the other thread "Binary State"? heheh

Check out my new BS amp!! :)

"Check out my new BS amp!! "

:D I never made that connection SC.

Good suggestions Yves. Although "PWM amplifier" is the closest current term to use for them in general. Although it doesn't have that pizzaz (at least to me).

In regards to UcD, that's the magic of USB, it is easy to convert it to any format (input/output) you want. It also (can) carry analog audio and video signal as well. So it is easy to implement to just about any application. Same goes for Firewire (iLink/IE3-1394).


...

Siriusly:

Actually switching output stage is an apt way to describe a pulse width modulation scheme. They are one and the same.

The question becomes this, is the PWM scheme handled by digital means or analog means, and is it fed an analog input or a digital input.

These, as well as what is used for the linear comparator (for pulse variation) are what distinguishes the various designs apart.

Cheers,

I'm just looking for a good name that Joe Average can use...

People have no need for an lateral-piston induced wheel engaging motion entity? They want a car.

John (and everyone else)

can we go with PWM then? it seems to describe how the speakers are fed power and encompasses any source signal

just so everyone knows what to expect when they click on this thread (in which case 'digital' would do) and until someone comes up with a better acronym than BS *LOL*

PWM it is (for now).

Politically
Wrong
Misnomer

PWM

Hah hah!


...

*LMAO* ok, changed the topic and 1st posting

So when does anyone think we'll see reasonably priced standalone digital amps?

Right now it's like the early days of digital projectors, where it cost 5X for 1/5 the complexity and weight.

Consider the Panny XR55 as a stand alone with some extras. :D




...

Noah,

AV123 are working on something reasonably priced (http://av123forum.com/showthread.php?threadid=10683).

IMO the eAR 202, at $600 for 200Wx2 isn't astronomical :)

i'm not aware of a class d style amp made by theta yet....

it's also hard to classify something as an amplifier versus an integrated when an amp has a digital input and volume control.

The old classification systems get thrown out and "separates" must be redifined. eventually if they improve to the point that pcm->pwm surpasses standard d/a converters then there may no longer be a need for separates in their current form.


The yamaha mx-d1 has decent measurements on stereophile and the published stats in the manual. I wonder if anyone has forked over close to three thousand bucks for one of these units. They certainly aren't cheap despite being from yamaha.

OK, I'll take ThetaDigital off the list for a bit until we can find solid references.

The old classification systems get thrown out and "separates" must be redifined. eventually if they improve to the point that pcm->pwm surpasses standard d/a converters then there may no longer be a need for separates in their current form.

which is what PSaudio are saying with their GCC control amplifiers (http://www.psaudio.com/products/gcc_control_amplifiers.asp)


Edit: Theta Digital - news on Stereophile (http://www.stereophile.com/images/newsletter/905Bstph.html)
Theta Digital, for example, had a static display on the floor of the Dome, but that didn't stop me from investigating what the company was up to. Taking pride of place on their stand was a relatively small power amplifier that nevertheless packed seven 150W channels of highly efficient class-D (PWM) power into its chassis. The Virtu PowerDAC features an all-digital signal path—it has digital inputs only, on four S/PDIF RCA jacks, for L/R Front, Center, L/R Surrounds, and L/R Rears (Sub is ignored)—and uses new technology from English company Zetex (http://www.zetex.co.uk/) for converting PCM digital audio to the PWM format used to switch the amplifier's output devices.
unfortunately there are no references on their own site.

"AV123 are working on something reasonably priced."

Interesting, thanks.

If you are including receivers you can add the Sherwood Newcastle R-903 TruDigital™ 6.1.

SiriuslyCold:

That's the item I missed -- I knew they (Theta) had a switching amp solution in the works, but I didn't have any specifics on it.

I think there will be a bit more specifics come CES. THis was the first public showing, and in January more details will likely be available.

Best,

Noah,

We're discussing seperate amps. There's another thread discussing receivers in the forum.

Best,

Sorry for getting side track, but what is class A/B amp? I have heard it all the times but never know what it means. Thanks for the post.

Sorry for getting side track, but what is class A/B amp? I have heard it all the times but never know what it means. Thanks for the post.


this is beyond the scope of a simple response.... you should look this up on a website like audioholics or something.

Sorry for getting side track, but what is class A/B amp? I have heard it all the times but never know what it means. Thanks for the post.

Some reading:

http://www.hometheaterhifi.com/volume_1_1/v1n1amps.html#ClassOfOperation

and this one includes information on Class D:

http://www.extron.com/company/archive.asp?id=ts122001&version=print

Dsmith901, thanks for the link. I'll check 'em out when I get home as I can't view it from work due to Websense software. However, I used Google and found few answers. Blazar is right. I fell asleep reading those lengthy explanation. Oh boy, I'm sorry that I ask. Thanks guys.

SiriuslyCold:

That's the item I missed -- I knew they (Theta) had a switching amp solution in the works, but I didn't have any specifics on it.

I think there will be a bit more specifics come CES. THis was the first public showing, and in January more details will likely be available.

Best,

John,

do keep this topic updated - you're more likely to come across news earlier than anyone :)

SC,

Don't forget about the Sunfire Flat Eight.

Also, there are tons of proamp out there. Almost all of them have some sort of PWM amps.

Crown
Crest
QSC
Ashly
Behringer
Yamaha

List could go on and on. I know this is mainly for the "NEW kids on the block" but there are some cool proamps out there that haven't been mentioned here on AVS.

A lot of pre/pro users here. I bet they don't even know they are using somekind of PWM amp. :D :D :D

We don't want them to miss anything like this...

http://www.yamaha.com/yamahavgn/Images/ProAudio/Product/Views/PC9500_front.jpg


...

These are using UcD aplification:

Van Medevoort MA240 (http://www.audioart.nl/nl/products/ma240.html)

CIAudio D-100 (http://www.ciaudio.com/D100.html)

CIAudio D-200 (http://www.ciaudio.com/D200.html)

GED, I had Sunfire Flat8 in the original list, but in view of the discussion in the other thread, I'll take it off list until the dust settles ;)

didn't want to put pro-amps on the list initially, but there is a CarverPro ZR1000 review at AA (http://db.audioasylum.com/cgi/m.mpl?forum=amp&n=21654)
http://www.carverpro.com/images/zr1600-lg.jpg (http://www.carverpro.com/zramps.html)


Yves, thanks for the heads up on Van Medevoort, i'll put it on the list - is it shipping yet?

CIAudio is already there ;)

Well, here's another. The site is in english but the page with the amp is missing, so I give you the dutch link:

Mindcraft Media Amp One (http://www.mindcraft.nl/mediaampone.htm)

Mindcraft makes HTPC units and have recently added an "audiophile 5 channel amp"

This is for sure a Hypex OEM customer - they use 5 channels of UcD180 (possibly modified) in a single box.

They're not hiding this fact, the module photo's and references to Bruno Putzeys are on the page.

http://www.lcaudio.com/predpic1.jpg (http://www.lcaudio.com/index.php?page=37)
these amps certainly look sleek, which is why the pro amps look sucky in comparison

Yves, is the MediaAmp One a AV receiver with UCD amps? wow... wasn't someone asking about this somewhere?

I agree. Keep out the proamps out of the mix. Out with the old, in with the new. (and much more cool looking amps).


...

That reminds me of my old departed Sansui. :)


...

SiriuslyCold,

Yeah but can't remember who was asking...

Seems I was wrong, the Media Amp One is an option built into the HTPC offering:

1) A fully installed and equipped HTPC with Windows Media Center edition and audiophile sound card (balanced out channels)

2) The Media Amp One is in fact a 5 channel optional amp with balanced connections. Judging from the photo's they are using the improved module with the AD8620 opamps. There's no word on the size of the transformer, or if they use a switchmode PS, but the caps are visible - 44.000uF of Kendel caps - they are not cutting corners... but no stand alone :( :(

And the LCAudio predator up there is using ZAP modules by LCaudio - these are DIY modules - on DIYaudio the ZAP and UcD are compared a lot, sometimes even a bit of fighting going on about "who's best"

Hmm... Money could be made by retrofitting low/midrange receivers with what they lack most - big power and good amps....

Add to the list building Hypex UcD based amplifiers:
* Kevin Haskins from DiyCable, http://www.diycable.com/main/default.php
* Adire Audio, USA distributor for Hypex, http://www.adireaudio.com/Home/UcDAmps.htm

Their prices are reasonable when compared against other UcD retail amplifiers. If you are interested in 6channels of UcD400 amps, let me know.

I've mentioned Adire Audio a few times on this forum, didn't do it in this thread though.

meanwhile I think this Saturday I'll go take a look/listen to the sneak peek of the new little 'Mole (http://www.echoloft.com/cgi-bin/buysell/YaBB.cgi?board=hifi&action=display&num=1130254895)

http://img426.imageshack.us/img426/3213/cas3280pixel1bf.jpg

30W/ch @ 4 Ohms, 0.05% THD 15W/4 Ohms, 20Hz-20kHz +/-0.5dB, 98dB S/N Ratio but reportedly at 70K Yen (~US$600) it ain't exactly cheap

I think there will be a bit more specifics come CES. THis was the first public showing, and in January more details will likely be available.


there's a press release

http://www.thetadigital.com/press-release/virtu-09-05.htm

I wouldn't call an amp "digital" unless it actually used numerical processing to modulate the pulse widths in discrete increments. The common thing about these amps is that they appear to be class D, with PWM output stages and passive recovery filters on the outputs.

There are additional ways in which class D can be broken down. The classic class D model of a constant +/- pulse stream, modulated in percentage of positive and negative duration, could be called "class AD" and an amplifier in which the pulses are also width-modulated but are positive- or negative-going depending on the polarity of the signal could be considered "class BD."

I know, changed the topic title in the first posting but couldn't do the same for the forum topics listing. maybe someone (mods?) can help

I wouldn't call an amp "digital" unless it actually used numerical processing to modulate the pulse widths in discrete increments. The common thing about these amps is that they appear to be class D, with PWM output stages and passive recovery filters on the outputs.

There are additional ways in which class D can be broken down. The classic class D model of a constant +/- pulse stream, modulated in percentage of positive and negative duration, could be called "class AD" and an amplifier in which the pulses are also width-modulated but are positive- or negative-going depending on the polarity of the signal could be considered "class BD."

Well, self-oscillating designs do turn the transistors on/off but not in a given frame of time, so it's not "binary" or "digital"... they are in fact analog amps, analog "pulsing" amps :D like the UcD...

Bob Lee:

I try to very particular, and don't like the use of "digital" when describing a Class D amplifier without a digital input.

If you have a digital input, you have to use numerical processing to modulate the pulse widths, unless you've actually got a DAC in front of the PWM stage.

Cheers,

John, on a sidenote, how's the multichannel UcD test coming along?

Yves:

It's on hold unfortunately. I have two different sets of active loudspeakers in back to back that will have the UcD shutdown until early next year.

On the up side, the amp is going to be out on line to an online publication in the near future for review so it will get some use in the interim :)

Best,

I wouldn't call an amp "digital" unless it actually used numerical processing to modulate the pulse widths in discrete increments. The common thing about these amps is that they appear to be class D, with PWM output stages and passive recovery filters on the outputs.

There are additional ways in which class D can be broken down. The classic class D model of a constant +/- pulse stream, modulated in percentage of positive and negative duration, could be called "class AD" and an amplifier in which the pulses are also width-modulated but are positive- or negative-going depending on the polarity of the signal could be considered "class BD."

A better term for these amplifiers would be switching amplifiers... not digital..

I'm still pushing the term Pulsing Amplifier :D

John, if possible, please PM me with the information about this online publication of the test, thanks!

might be fun to conduct a scientific poll :) *LOL*

Bob Lee,

Thank you!






...

I am overall wondering what will accomplish the best sound quality:

1. A switching amplifier connected to a source d/a converter (ie benchmark dac 1) without volume control.
2. A switching "integrated" with built in PCM to PWM conversion from a digital source with direct digital volume control. (despite signal to noise not being 120db like it is on some professional dacs).
3. A switching amp connected to a preamp with a source DAC or use of internal DAC. Most high end pre-amps only achieve 114 db signal to noise (or close).
4. A switching amp with it's own volume control (ie gain cell PS Audio products) - this solves the problem of quality volume control (voltage gain) but still requires a d/a converter. The ps audio products are also fairly expensive.

I would like to see pcm->pwm integrated units with signal / noise as high as standard professional dacs (116-120db). The TacT units get pretty close but are astronomical. Prices can and will reduce for like quality integrated amps.

I know this thread is about digital switching amps but does anyone else agree with me that voltage volume control would ideally belong in the amp itself... The only amp I'm aware of that meets this criteria is the Ps Audio GCC line. If only ps audio had a pcm-pcw converter it would be perfect.

I think the ideal term is "class D."

Don't do volume control in the digital domain (PCM) because you will lose resolution - of course if you feed a DAC or amp 24/96 or even higher this would be less obvious.

So when does anyone think we'll see reasonably priced standalone digital amps?


some news from Acoustic-Reality (http://www.acoustic-reality.com/) (click on What's New)

eAR 102 stereo power amplifier is a coming bargain
eAR 102 is a 2 x 100 Watt RMS stereo power amplifier with ICEpower technology. eAR 102 is also the smallest amplifier ever made at Acoustic Reality. It performs half the power of eAR 202. The first eAR 102 will be available Jan. 2006. To its very low price it may be difficult to deliver enough. The introduction price will be US$399 / EURO 399 / 2999 DKR
Note: eAR 102 do not match the size of eAR 202, 501 and 1001.
The size of eAR 102 is ultra compact: H x W x D = Just 21.5 x 21,5 x 6,5 cm. The weight is only 2,2 kg.

Thanks for the link.

Although $2/W $200/ch is still high IMO.

I'm looking for a 6-ch amp to biamp my fronts; the AV123 seems like a great value.

Don't do volume control in the digital domain (PCM) because you will lose resolution - of course if you feed a DAC or amp 24/96 or even higher this would be less obvious.

the switching amplifiers do voltage gain volume control if they have a volume control, not pcm digital attenuation. This is theoretically the ultimate form of volume control.

That I agree, it doesn't influence the digital signal - it does mean, however, that with a purely "digital" class-d solution, you can't really have a preamp and seperate amps, as the volume is done in the amp section.

Of course one could create a pre that sends some kind of signal to the seperate amps to do voltage based volume control.

And yes, $1 (or rather €1/watt) seems to be the starting price for good class-d - it's cheaper than comparable class-AB in my opinion, but you shouldn't expect miracles either (it won't outperform amps 10 times as expensive like some panny lovers would like to believe - no trolling intended)

The inherent quality of good class-D amps might be very high to start with, relative to price, but when the load gets tougher, you'll need to pay for it. High amperage in low impedances is still difficult, also for class-D.

Hypex UcD400 modules for example, will do 200W in 8 ohms when given a good PS, easily double into 400W into 4 ohms (they can handle 20A peak current) - however in lower impedances, the output will drop back. This is where the krells of this world step in, with multiple transistors per channel.

However UcD700 is a step closer to heaven for extremely difficult loads. 350W in 8 ohms, with a possible 30A current - that's quite impressive.

Bob Lee:

I try to very particular, and don't like the use of "digital" when describing a Class D amplifier without a digital input.

I believe it depends on one's perspective. In its very basic forms, human hearing and sound transmission is analog by nature. so any amplifier driving into a speaker has to output an analog signal by definition. Thus, from that perspective, you cannot have a digital amplifier (driving into a speaker). Unless of course we discover a digital speaker, :) and ultimately digital hearing.

On the flip side, any analog signal is measured in terms of electrons or finite charges they carry with them. As such, any analog signal is by its definition digital (quantization, to either an electron charge or even finer quarks). From that perspective, any analog amplifier is a digital amplifier.

going back to this topic, if you think "digital' as in the forms of "on" and "off", I would argue that the bulk of the amplification in a typical class D amp, whether analog or digital input, is done with a bunch of "on" and "off"s. so that qualifies it the 'digital' title.

so it is fair to call them digital. Of course, there are different degrees of "digitization" among those digital amplifiers but that's just a fact of life and doesn't foundamentally change the picture.

In short, it is a fair representation to call class d amps "digital".

That I agree, it doesn't influence the digital signal - it does mean, however, that with a purely "digital" class-d solution, you can't really have a preamp and seperate amps, as the volume is done in the amp section.


sure you can. your vollume control is just a (digital) multiplier (implemented with either hardware or software), and your DSP can perform all sorts of processing or signal switching.

the switching amplifiers do voltage gain volume control if they have a volume control, not pcm digital attenuation. This is theoretically the ultimate form of volume control.

I'm not sure I understand what you are referring to here with regard to voltage gain volume control. Are you talking about high quality potentiometers (like those offered by DACT), stepped attenuators, transformer/magnetic volume control or digital volume controls (like Cirrus Logic CS3310, Burr Brown PGA2310/2320, Wolfson WM8816, etc.)?

going back to this topic, if you think "digital' as in the forms of "on" and "off", I would argue that the bulk of the amplification in a typical class D amp, whether analog or digital input, is done with a bunch of "on" and "off"s. so that qualifies it the 'digital' title.

so it is fair to call them digital. Of course, there are different degrees of "digitization" among those digital amplifiers but that's just a fact of life and doesn't foundamentally change the picture.


Again I have to disagree here. "Digitizing" is taking a signal, and "rounding" it's value into the nearest discrete "number" you wish to put on it. You do this a given amount of times per second.

May it be 1 bit at a megahertz sample interval (DSD) or 16 bits every 44.000 of a seconds, yes, then you are digitizing.

However, the self-oscillating class-D (for example UcD) isn't measuring in intervals, it's doing so continously, and can turn the output transistor to 0 or 1 at any given time and later recreating the input wave *also* in an analog way, by putting the outputted power into a coil. This switching couldn't be stored "digitally" as it can switch at any given discrete moment in time- if you'd have to store it you'd have to slash it up in intervals again.

Put in other words, you can't represent into a list of numbers how the transistors in a UcD design have switched in a one second time frame. Sure, you can give me a row of zero's and one's, but you cannot exactly say when these zero's and one's occured. You lack the exact moments in time in your "number list" - in a PCM stream this is clocked, and then it is a digital representation.

This is a good case *against* calling this type of class-D digital - this is analog.

Of course, if you see "analog" as the most intense and ultimate form of digital quantization (on an atomic level) then I have to give you the advantage. But then class A or AB is also digital, as you are smacking around a finite number of electrons back and forward... :D

I'm not sure I understand what you are referring to here with regard to voltage gain volume control. Are you talking about high quality potentiometers (like those offered by DACT), stepped attenuators, transformer/magnetic volume control or digital volume controls (like Cirrus Logic CS3310, Burr Brown PGA2310/2320, Wolfson WM8816, etc.)?

You don't alter the input signals amplitude to control the volume - you control the rail voltage that is fed to the power transistors. Since the transistors are always on or off, the same feeded signal can be made "harder" or "softer" at the output if you change the voltage on the rails feeding the transistors. In conventional designs, this rail voltage is fixed (in class A, AB, and D) - Class H designs alter the voltage of the rails also, but for a different means: They track the incoming signal to increase efficiency.

You don't alter the input signals amplitude to control the volume - you control the rail voltage that is fed to the power transistors. Since the transistors are always on or off, the same feeded signal can be made "harder" or "softer" at the output if you change the voltage on the rails feeding the transistors. In conventional designs, this rail voltage is fixed (in class A, AB, and D) - Class H designs alter the voltage of the rails also, but for a different means: They track the incoming signal to increase efficiency.

Sounds interesting, but what devices are used to control the rail voltage? I'm building a UcD based multichannel amp and haven't come across any reference to this (or if I have, I've just overlooked it).

… any amplifier driving into a speaker has to output an analog signal by definition.

I have the slightest issue with this statement, but i can't quite put my finger on it. :p

a speaker generates sound when a current passes thru it and moves its voice coil - depending on how much current/voltage, creating sound waves. Amplifiers supply this power to the speakers, whose power output once again depends on the signal going into them.

How this power output is controlled is the issue here - and switching amps do it by swtiching on and off (more reading here (http://www.psaudio.com/articles/sdat.asp)) and, it's this on-off state that's made people label it - digital.

it's a conveninent label for the general public I guess because LP=analog and CD=digital but it is a red herring.


… Put in other words, you can't represent into a list of numbers how the transistors in a UcD design have switched in a one second time frame.

but you don't have to - the list of numbers is already stored on the CD in PCM format. now if you could directly use this list of numbers to control(determine?) the list of numbers the UcD needs... (you'd have a Equibit amp) :D

… in a PCM stream this is clocked, and then it is a digital representation.

my JPEG image of Maria Sharapova isn't clocked, but it's still a digital representation of her picture. ;)

http://unangelic.org/stupidlogic/uploads/capt.ctmm10107061909.pilot_pen_sharapova_ctmm101.jpg

"Digitizing" is taking a signal, and "rounding" it's value into the nearest discrete "number" you wish to put on it. You do this a given amount of times per second.

that's just one definition or interpretation of "digitizing".

PWM to me is a one-bit digitization of analog data. and I believe that is fairly well accepted and understood. of course, each one of us can create our own definition. Whether it will be as widely accepted by others is a totally different issue.

a speaker generates sound when a current passes thru it and moves its voice coil - depending on how much current/voltage, creating sound waves. Amplifiers supply this power to the speakers, whose power output once again depends on the signal going into them.

And the current / voltage information is analog to speaker.

How this power output is controlled is the issue here - and switching amps do it by swtiching on and off (more reading here (http://www.psaudio.com/articles/sdat.asp)) and, it's this on-off state that's made people label it - digital.

a class D amp doesn't feed its digitzed output (PWM waveforms) directly into a receiver. It does so through a low-pass filter, which converts the pwm waveform into analog voltage (effectively a DAC).

So the combination of a pwm output stage and the low-pass filter forms the digital amp and outputs an analog signal.

You don't alter the input signals amplitude to control the volume - you control the rail voltage that is fed to the power transistors.

that wouldn't be necessary: you can simply multiple a pwm or pcm or bitstream signals in the digital domain and then feed that signal to the amplifier. For example, multiplying the signal by a factor greater than 1 increases its volume and multiplying the signal by a factor less than 1 decreases its volume.

let me use a simple example. see you are dealing with a 4-bit pcm signal, which takes the form of 0110 (equates to a value of 6) at this particular moment. see you want to double its volume (to 12), you just shift it 1 bit to the left, 1100 (equates to 12). feeding that
signal to a class d amp (either directly or through a dac) will double the output voltage.

or you can shift it to the right by 1 bit to reduce the volume by 50%, 0011 (which equates to 3).

the same principle applies to your typical 16-bit PCM used by your CD, or DTS / DD signal on your DVD.


In other words, you want to do volume control or processing (of which volume control is a form) in the digital domain, and in the pre-amp section, not in the amplifier.

no need to alter rail voltage dynamically for a class d amp - too complicated and without any meaningful gain.

However, the self-oscillating class-D (for example UcD) isn't measuring in intervals, it's doing so continously, and can turn the output transistor to 0 or 1 at any given time and later recreating the input wave *also* in an analog way, by putting the outputted power into a coil. This switching couldn't be stored "digitally" as it can switch at any given discrete moment in time- if you'd have to store it you'd have to slash it up in intervals again.

it looks like that you were trying to say that the timing of those 1s and 0s in a PWM class D is analog: that when to turn those transistors on or off is continuous in time. That I agree completely.

However the same (that certain elements of digitization is analog) holds true for pretty much all digital signal: most digital circuitry has a "threshold" beyond which (usually above which but sometimes it can be below which) an analog character (mostly voltage or current) is considered 1 or 0. This is foundamentally how jitter comes about as different circuitries may recognize a signal as 1 or 0 faster or slower than others.

In conclusion, unless you go to quantum computing (at the present time), you aren't going to have this "absolute" digitization, as our digitization is built up on analog measurements.

I'm not talking jitter or the obvious errors in timing at which you sample the signal. I'm saying that the switching is not "on" for a delta T or "off" for a fixed delta T. It's variable, it's not made on some crystal defining an interval for it.

I'm not talking jitter or the obvious errors in timing at which you sample the signal. I'm saying that the switching is not "on" for a delta T or "off" for a fixed delta T. It's variable, it's not made on some crystal defining an interval for it.

why does that have to be true for a format to be digital? It doesn't seem to be critical to me at all. Naval signals for example aren't transmitted at fixed intervals and people do consider them digital. So is moorse code as well.

Foundamentally, digital signals robustness comes from its full "on" or full "off" nature. and that has zero to do with sampling frequencies or intervals.

Great discussion guys! Don't have much time but let me contribute some at least.

These new forms of PWM amplifiers have all evolved to different and unique variants of the conventional design. So much so that some are even hard to pin to which side of the fence it belongs. What is obvious is that it seems that each maker are "branding" their technology. Class-T for Tripath, Class-Z for Zetex and so on. Marketing propaganda or not, it seems that the move is to indistinguish their design from Class-D.

While many are still closely related to the conventional design. Some have deviated enough that the final design is unorthodox. Some even employing designs that span across the whole defined official classes of amplifier. So which side of the fence do they belong? So far no proper authority has laid their hands on it. One thing is for certain is that ALL these digi-amps uses some means of Pulsed Width Modulation and that is what they all have in common.

Out of time but more to come... :D


...

"Pulsing amps", my dear GoldenEarDrums ;)

Just kidding, call it what you want, I'll just shut up and listen to the glorious sound coming out of my speakers, doesn't matter how it is created, as long as it sounds good to me :D

As for digital or not - Bruno Putzets, who designed UcD has explained himself that he doesn't see his creation as "digital" - OTOH he doesn't shy away from the word class-D: UcD is "Universal Class D"

As for digital or not - Bruno Putzets, who designed UcD has explained himself that he doesn't see his creation as "digital" - OTOH he doesn't shy away from the word class-D: UcD is "Universal Class D"

it is important to keep in your perspective that Bruno's view is just one of many perspectives, however impressive his credential is.

no matter how people call it (which for the most part is for marketing purposes), end of the day, most of those amps have the guts of a pwm amplifier that works like a very fast light switch that goes on and off and the duration of its "on" or "off" state depends on the amptitude of the signal (which can be presented to the amp in either digital or analog format).

so it is fair to say that it can be called either a digtal or analog amp, depending on which angle you favor.

Ok, fair enough, everyone seems to have an opinion, I don't feel the need to elaborate it further. :)

One way or another.... Voltage gain appears to be THE way to control volume. This brings us back to the basic concept that the volume control for this type of technology should be in the AMP itself and not in a pre-amp to achieve the best over accuracy / signal to noise or whatever you want to call it.

In a way this sortof swings the pendulum back towards the concept of an integrated amp being ideal.

The only trouble with the integrated concept is the upgrade path is all or nothing.

I'm curious if you could have a new type of interconnect that transmits a PWM signal to the ampifier from the pre-amp.... would this be possible? This way the pcm-PWM conversion could occur with volume control in the pre-amp but then also be a pure pwm signal that goes to the amp. Would this type of signal to highly susceptible to noise? Of course to be universal this would require an industry wide change that is unlikely to occur. I'm not even sure it would even make a positive impact on the sound by doing all this either.

One way or another.... Voltage gain appears to be THE way to control volume.


not really. Many people have argued, and I tend to agree, that current going through the coil is the only thing matters. This advocates the use of current amps in the power amplification stage - something the tube folks tried many years ago to solve their damp factor issues.

And you are startign to see the use of current feedback amps in the high-end and headphone amps (like the tpa6120).

This brings us back to the basic concept that the volume control for this type of technology should be in the AMP itself and not in a pre-amp to achieve the best over accuracy / signal to noise or whatever you want to call it.

Even if your preceeding statement is true, I don't see how that would lead to this conclusion.

I'm curious if you could have a new type of interconnect that transmits a PWM signal to the ampifier from the pre-amp.... would this be possible?

Absolutely. Just use the good old copper wires and your "new" interconnect will work perfectly.

I think it sounds like thats what PSAudio did - and they call them "Control Amplifiers"

Back to the point that timing of a pwm amp being analog. You could conceivably use the pcm signal to control the duration of the pwm on / off state and have the amp being entirely digital.

For example, if you see a signal of 0101 (again, in a 4 bit pcm format), you turn on the output device for 5 cycles (or a multiple of 5 cycles). in this way, all you need is a sqaure wave generator and a down counter that automatically resets itself.

something like this can be even implemented ina fpga device. and can be very fast.

those pwm amplifiers are essentially your switching mode power supply. Except that in the case of a power supply, the "input' signal is a reference voltage / current. You can take such a power supply and feed its ref node with an audio signal and it should sign.

As a matter of fact, there are people using sg352x devices and mosfet gate drivers to make high performance pwm amps - IRF's IRAudAmp1 is such an example.

on the notion of digital amps, FM (frequency modulation) amps are probably the very first digital amps we have seen.

There's an error in the list:

The Van Medevoort is a UcD design but doesn't use the Hypex UcD modules.

Oh, and the Philips DFR9000 is using UcD as well, about 60W/channel into 8R! This is a 6.1 receiver with DAB radio and HDMI upconversion+scaling! - who was looking for a UcD receiver again????

that wouldn't be necessary: you can simply multiple a pwm or pcm or bitstream signals in the digital domain and then feed that signal to the amplifier. For example, multiplying the signal by a factor greater than 1 increases its volume and multiplying the signal by a factor less than 1 decreases its volume.

let me use a simple example. see you are dealing with a 4-bit pcm signal, which takes the form of 0110 (equates to a value of 6) at this particular moment. see you want to double its volume (to 12), you just shift it 1 bit to the left, 1100 (equates to 12). feeding that
signal to a class d amp (either directly or through a dac) will double the output voltage.

or you can shift it to the right by 1 bit to reduce the volume by 50%, 0011 (which equates to 3).

the same principle applies to your typical 16-bit PCM used by your CD, or DTS / DD signal on your DVD.


In other words, you want to do volume control or processing (of which volume control is a form) in the digital domain, and in the pre-amp section, not in the amplifier.

no need to alter rail voltage dynamically for a class d amp - too complicated and without any meaningful gain.
A very good point and it is logically sound. :)
However, this procedure will require tremendous processing. Imagine recalculating every bit (no pun intended) of information even with the slight change in volume (gain).

Each one of these digi-amps have a unique way of handling volume control. Equibit's approach maybe the best that I have seen so far. It uses PSVC (Power Supply Volume Control) which varies the (fixed) voltage of the PS via a controller built in the chip and is completely separated from the signal path therefore providing the cleanest unhindered volume control system.


...

You don't alter the input signals amplitude to control the volume - you control the rail voltage that is fed to the power transistors. Since the transistors are always on or off, the same feeded signal can be made "harder" or "softer" at the output if you change the voltage on the rails feeding the transistors. In conventional designs, this rail voltage is fixed (in class A, AB, and D) - Class H designs alter the voltage of the rails also, but for a different means: They track the incoming signal to increase efficiency.
Again, these digi-amps varies in designs and voltage control implementation. The PSAudio digi-amp for example uses its Gain-Cell module technology to adjust its volume at the preamp stage.


...

a class D amp doesn't feed its digitzed output (PWM waveforms) directly into a receiver. It does so through a low-pass filter, which converts the pwm waveform into analog voltage (effectively a DAC).

So the combination of a pwm output stage and the low-pass filter forms the digital amp and outputs an analog signal.
You can feed the output directly to a speaker and basically making it the LPF and the speaker itself will interpret this signal and output it in analog form (soundwave). Of course with the conventional design, noises and transient frequencies will be part of that signal as well. The LPF's purpose is to take out these noises and unwanted signals out and to somehow "smooth" the signal before it reaches the speaker.

The new Yamaha LSI chips are the only one designed to bypass the LPF completely AFAIK.


...

Here are two more for your list, both use ICE amps

Midgard Audio

http://www.midgardaudio.no/www/

Bertram

http://www.audiokabel.dk/eng-main.htm

Bertram are the cheapest ICE based amps you can find, but he needs to get some help with his homepage cause it's a mess

thanks

whats it with europeans and digital amps.. :D

and strangely, the Brits are oblivious (well, except Sonneteer)

However, this procedure will require tremendous processing. Imagine recalculating every bit (no pun intended) of information even with the slight change in volume (gain).

I am not quite sure how much "processing" power it needs. those digital volume controls chips are a dollar a dozen (the upc line from National for example) and each controls 2 or 3 channels too.

Multipliers are some of the most basic elements of digital circuitry. and if you want, you can even use a memory chip for that - I actually have a patent on that.

It uses PSVC (Power Supply Volume Control) which varies the (fixed) voltage of the PS via a controller built in the chip

it essentially controls the resistor divider on the voltage feedback path in the smps.

and is completely separated from the signal path therefore providing the cleanest unhindered volume control system....

multiplying in the digital domain would be the cleanest path.

Here's one more

http://www.lcaudio.com/index.php?curr=2

SC,

Also add Flying Mole. Those guys are ex-Yamaha "Digital" engineers that formed their own company. Great products but looks so generic.

http://www.flyingmoleelectronics.com/


...

...
multiplying in the digital domain would be the cleanest path.
I agree with you, it is ideal. In fact similar logic in DSP for EQ, effects and etc but the processing on these pales in comparison. To reprocess the whole dynamic sound in realtime either bit-by-bit or even byte-by-byte is a tremendous processing tasks.

... those digital volume controls chips are a dollar a dozen (the upc line from National for example) and each controls 2 or 3 channels too.I'll go check but IFAIK these digital attenuators are for "mechanical" control. Unless I missed the one for audio. Can you give out the link to National? TI Equibits PSVC controller circuit is similar to what you describe but it still just a controlled step-up/step-down circuit to control the PS.


Multipliers are some of the most basic elements of digital circuitry. and if you want, you can even use a memory chip for that - I actually have a patent on that.
Well now... I'd like to hear more on watcha got. :)


...

LCAudio and the Moles were there from the beginning :)

Sorry SC! :D :D :D


...

haha no worries ;)

it's amazing how European companies have taken PWM to heart - B&O & Hypex and the people who use their amps dominate the list,

Back to the point that timing of a pwm amp being analog. You could conceivably use the pcm signal to control the duration of the pwm on / off state and have the amp being entirely digital.

For example, if you see a signal of 0101 (again, in a 4 bit pcm format), you turn on the output device for 5 cycles (or a multiple of 5 cycles). in this way, all you need is a sqaure wave generator and a down counter that automatically resets itself.

something like this can be even implemented ina fpga device. and can be very fast.
This is how a pure digi-amp work (like Equibit) if I am getting you right. Except it is coupled with a triangle wave instead (to produce a square wave).



...

those pwm amplifiers are essentially your switching mode power supply. Except that in the case of a power supply, the "input' signal is a reference voltage / current. You can take such a power supply and feed its ref node with an audio signal and it should sign.

As a matter of fact, there are people using sg352x devices and mosfet gate drivers to make high performance pwm amps - IRF's IRAudAmp1 is such an example.
IRAudAmp1 is a self-oscillating design similar to UcD of which, looking at from a different angle is also similar to a Tracking PS amplifier or "Tracking Down Converter" as Bob Carver would name it.


...

the National chips are LM197x series digital pots.

The IRAudAmp1 (and 2) are those 'analog PMW" amps, to follow the prior discussion, that take an analog input, digitze it and send it into a LPF.

The Carver scheme is a little different in that it alters the rail voltage "discretely", meaning that it has a high and low rail voltage and if the amp senses a high signal, it will switch to the high voltage rail. the amplifier itself is still linear.

Thanks for the info millwood. I did check out the National LM197x series digital pots and they are in fact built for audio but the only digital part of it is the gate control for the volume. It also takes in an analog audio input and an attenuated analog audio output. So it is not bit-dynamic.

The TI Equibit chips has similar built in circuit for controlling the PSVC.

I do like your idea of this bit-dynamic VC and would like to know more about your patented product.

Regarding Carver's work, that is a pretty good description with the exception that UNLIKE CLASS-H it only has one voltage rail and not two or more. :D :D :D Sorry, just had to VENT that out as I had a lenghty discussion in another thread. Just in case somebody is lurking.


...

I know this is about two pages late.....but instead of wondering what the proper terminology is for D-class amps.....why not just call them D-class....that is completely accurate...PWM, Digital, Digi, are all either inaccurate or ubiquitous on some level but not nearly descriptive enough to cover the entire class.....break it down from D-class at the individual amp....D-class, emphatically, isn't digital....but by some it can be viewed as such....


so simplify....

D-class


that's just a complete novice's take on the subject (or lack there of)

Here's yet another one

Embla. ICE based

http://www.emblaaudio.no/

with these modules it appears that just about anyone with a soldering gun and the ability to fabricate a chassis can put these together and come up with a product.

It would appear that the main differences will be in chassis, connectors, transformer....

Well I guess for the most part this has been the case with other solid state designs as well.... only god knows what you actually get from boutique manufacturers anyway.

I do like your idea of this bit-dynamic VC and would like to know more about your patented product.

it is actually very simple. think of a pot as a multiplier, that takes two inputs and outputs one. then, think about a multiplification table: it does multiplification by maping two inputs on a table and outputing the result. Well, a memory chip does that: it takes an input (on the address line), and outputs a result (on the output line).

for example, take a memory chip with 32 bit address line and 16 bit data line. You split the address line into hi 16 bits and low 16 bits. the high 16 bits contain your pcm data, and your low 16 bits contain your volume control levels. and the memory chip is pre-programmed with all the possible combinations. viola, you have a hardware implemented multiplier.

By programming the chip differently, you can pretty much implemented any multiplification scheme you want.

TEAC embraces Class-D with their Esoteric line AZ-1 pre-main amplifier (http://babel.altavista.com/babelfish/trurl_pagecontent?lp=ja_en&trurl=http%3a%2f%2fwww.teac.co.jp%2fav%2fesoteric%2fsz1_uz1_ az1%2faz1.html)

http://www.teac.co.jp/av/esoteric/sz1_uz1_az1/enhas_image.data_/images/enhas_image_01.jpg (http://babel.altavista.com/babelfish/trurl_pagecontent?lp=ja_en&trurl=http%3a%2f%2fwww.teac.co.jp%2fav%2fesoteric%2fsz1_uz1_ az1%2findex.html)

Another cool find SC.

I wonder how many will be displayed at CES 2006


...

at $4.5K, the amp is pretty expensive (pretty, and expensive), though; and meagre specs. I suppose we'll get more info when they actually start selling.

50W (1kHz,8 Ω load), 80W (1kHz,4 Ω load)
Impedance: 4 Ω - 16 Ω
Frequency characteristic: 10Hz - 80kHz

The attraction must be the iLink with the Universal player paired with it.

Cary Audio A 306 power amplifier (http://www.caryaudio.com/products/designer/a306.shtml)

http://www.caryaudio.com/graphics/products/a306.jpg

Say hello to Rotel RB1092 (http://www.rotel.com/products/specs/rb1092.htm)

http://www.rotel.com/products/images/RB1092.jpg (http://www.rotel.com/products/specs/rb1092.htm)

pwm stands for pulse width modulation, modulation is not what an amplifier does, in fact, modulation in an amplifier is distortion. an amp can have a pwm power supply but any audio amplifier that reproduces its input with pulse width modulation would have a very distorted signal. usually pwm is used to impose intelligence on a carrier, or to adjust to changes in a load impedance in power supplies.

KB9

dang, I thought we got this out of the way on page 1 (http://www.avsforum.com/avs-vb/showthread.php?p=6404197&&#post6404197) of this thread

Also, we're listening to distorted PWM sources :)

must be the 'good' distortion everyone keeps talking about similar to tube amps ;)

KB9KXH, take a peek: http://sound.westhost.com/articles/pwm.htm

Who has done extensive listening of the new Rotel 7 x 100 class D unit?

The stereo (2 x 500) and 500w mono units are coming out now.

must be the 'good' distortion everyone keeps talking about similar to tube amps


THE TUBE AMP SOUND IS due to the fact that some of these units are rooled off at 15k.
If the distortion can be pushed to frequencies above audible range then one can roll off higher , if one wishes to design the amps that way.
The reason they use to use class d mostly in subs was because, if you don't adress it, the "funky wave", comes in at around 3,000 cycles, and it is expensive to fix.

Schadenfreude,

These are Icepower amps - they don't roll off at 15khz at all - problem with icepower is that the freq. curve is very load dependent.

To get rid of that problem, Try Universal class d amps - UCD's. Ruler flat freq. response.

Class-d = subwoofer amps is a '90's statement.

These are Icepower amps - they don't roll off at 15khz at all - problem with icepower is that the freq. curve is very load dependent.

YVES, I did say "Use to use" and was not saying that the ICE MODULE itself was responsible for the roll-off but rather some individual amp designers attempting to get rid of the funky wave that starts coming in. Pushing that distortion up and out of the audible range needs to be addressed but when some people are trying to make an amp roll off in the upper frequencies (so as to get a softer, tube like quality), they don't have to compensate quite so much.

To get rid of that problem, Try Universal class d amps - UCD's. Ruler flat freq. response

If one looks at phase/delay issues and much tighter more specific plotting, there are still issues with some implementations, but I am incouraged that many are being addressed. I used to find most of these amps lacked depth/3 dimentionality of soundstage and was taken aback by their low noise floor (a good thing , but a differant thing).

Added Chapter Audio to main list.

http://www.chapteraudio.co.uk/image/553_RMP_COUPLET_01.jpg (http://www.chapteraudio.co.uk/)

To get rid of that problem, Try Universal class d amps - UCD's. Ruler flat freq. response.

Class-d = subwoofer amps is a '90's statement.

I don't know much about the UCD but to have "ruler flat frequency response", you will have to utilize post filter feedback (which the UCD may or may not use). The problem with that is the 90 degree phase shift introduced by the filter - which makes the stability design quite challenging.

I don't think it is that big of a deal to have roll-off at the high-end: there isn't much information (real life) in the >16Khz range anyway.

Bryston, hmm

http://www.bryston.ca/newsletters/91_files/vol9_iss1.pdf

ThetaDigital showed off their new Zetex powered Virtu PowerDAC

http://www.shows.soundstagelive.com/shows/avtour2005/sep09a/theta_powerdac.jpg (http://www.shows.soundstagelive.com/shows/avtour2005/ced_dly_sep09_1.shtml)

The new Rotel's are starting to get some very positive reviews. I still haven't had much opportunity to do critical, comparative listening though.

Onkyo A-1VL (http://www.eu.onkyo.com/products/product_en_43120.html)

http://www.eu.onkyo.com/ir_img/10192937_5f46a73a70.jpg (http://www.eu.onkyo.com/products/product_en_43120.html)

• Exclusive Onkyo VL Digital 2-channel amplifier
• 2 x 100 W, 8 ohms, 1 kHz (DIN)
• Separate toroidal transformers for L/R channels
• Separate mono circuitry design
• Low-impedance, copper bus plate
• Direct function for using as a power amplifier
• Audiophile grade parts
• Linear motor volume control
• Brass insulator
• Brass pinjacks
• High-grade, banana-plug-capable, transparent speaker terminals
• Pre-out terminal
• Main in terminal
• Extruded aluminium front & side panels
• Rugged chassis to prevent vibrations
• Full-function RI remote control

I know this is primarily a forum populated with electrical engineering wizards and not necessarily software guys, but as a former software guy myself, I'm particularly interested in how various companies are compensating for the distortion that has plagued "Class D" amplifiers with innovative software. Does anyone have any insight as to how ICEPower, Tripath and the others achieve this, and to what degree of success?

Apparently, the Danish venture (http://www.icepower.bang-olufsen.com/sw1022.asp) made a few waves at CES using their proprietary digital switching algorithm, interestingly developed by a scientist partnered up with Bang & Olufsen (those "speakers look good first, sound good second" guys -- kind of ironic). A speaker outfit called Sonic Weld that makes powered towers (http://www.icepower.bang-olufsen.com/sw2783.asp) with this technology won a "Best Sound" award or two from The Absolute Sound. Noteworthy, perhaps.

As an aside, I think it's underinformed to state that the only reason "corporate execs" are "forcing" research into this area is to exploit some perceived brand loyalty to anything labeled "digital." I think that stopped working in marketing in about 1986.

There are entire fortunes wisely invested in the very real challenge of increasing (or even maintaining) efficiency and accuracy of power amplification while simultaneously reducing heat dissipation and size requirements. The implications for smaller, more efficient amplifiers that produce little to no heat in cars, computers, and anywhere else where size and heat trump audio fidelity could make a company (or individual) very rich in the mass market, and many companies realize this.

That said, I personally am interested in sonic accuracy and power without distortion above all else in my own home theater and listening room. A close second is minimizing cost, followed by WAF. :-)

Should I start a new thread to discuss software developments in digital amplification and real-world test results of same, or is this the right place?

Just so no one shoots me for hijacking, here's one for the list:

http://www.audiodigit.com/index.php?section=84

Cheers,
Adam

Oh, and Bel Canto's Evo series uses Tripath, while their newer eOne series uses ICEpower, which they apparently say is superior.

From the 6moons.com review (http://www.6moons.com/audioreviews/eone3/prepower.html) of the latest Bel Canto:

"John Stronczer ... is equally convinced that the Danish ICEpower engine inside the S300 dances at a more rarefied level than his tweaked-to-the-hilt 4th-gen Tripath motor of the eVo series."

Might want to update first page to this effect.

Cheers,
Adam

@Ad-Rok,

Feedback design in these class-d amplifiers has changed so much that distortion levels have dropped considerably.

UCD (Ultimate Class-D) for example, takes the speaker loop into the feedback loop - dropping distortion very much & increasing linearity.

Other designs do use DSP power to correct errors, but I think the simplicity & good design of UCD is just fantastic.

There's lots of UCD OEM based products out there, but it never gets mentioned. Only the CIaudio D-100 and D-200 are "audiophile" grade amps using UCD, and have rave reviews.

There's a lot of studio monitor stuff using UCD also, I guess that's a different market...

Over on DIYaudio.com, there's a lot of comparison of DIY T-amps, ZAPpulse amps and UCD - you'll find massive measurement information if you take a week or so to work yourself through the supersized threads over there... 250 pages/thread is no exception! :)

@Ad-Rok,

Feedback design in these class-d amplifiers has changed so much that distortion levels have dropped considerably.

UCD (Ultimate Class-D) for example, takes the speaker loop into the feedback loop - dropping distortion very much & increasing linearity.

Other designs do use DSP power to correct errors, but I think the simplicity & good design of UCD is just fantastic.

There's lots of UCD OEM based products out there, but it never gets mentioned. Only the CIaudio D-100 and D-200 are "audiophile" grade amps using UCD, and have rave reviews.

There's a lot of studio monitor stuff using UCD also, I guess that's a different market...

Over on DIYaudio.com, there's a lot of comparison of DIY T-amps, ZAPpulse amps and UCD - you'll find massive measurement information if you take a week or so to work yourself through the supersized threads over there... 250 pages/thread is no exception! :)

Hmm, quite interesting! So UCD uses no software DSP and yet manages to minimize distortion? That's cool.

So funny you mention DIYAudio -- I was so close to building a D'Appolito MTM speaker myself from plans I found there, and then just bought Ascends because I got lazy and I think David Fabrikant sells speakers with great components (SEAS tweeters, etc.) and build quality at near-DIY prices. I suspect I'll spend several weeks planning my UCD amp build and then just go buy one if I find David Fabrikant's equal in the amplifier design world. ;-)

Best,
Adam

Look no further, his name is Bruno Putzeys and is an ex-philips engineer now working for Hypex - they have DIY modules to do UCD with. :p

Only thing that sets UCD a bit apart from the other solutions is the power supply - UCD works with "regular" power supplies, they don't recommend switchmodes.

So you wind up with large transformers and large caps like classic amps, and then teeny-weeny small amp boards pushing out anything between 180 and 700 watts at 4 ohms...

I'm driving B&W Nautilus 804's with them, Nautilus really is my kinda sound, but couldn't afford amps in the same league... Now I don't have to anymore, a pair of UCD400's with 500VA power supply drives them with ease.

DIYing UCD amps with Hypex stuff is more like lego than pure DIY stuff - you'll just have to put everything together, just watch the cabling and layout recommendations a bit and you can't go wrong.

There's prebuilt amps also, but not from hypex.nl directly

they don't recommend switchmodes.

they did so for good reasons.

Of course... A well designed SMPS is very costly - much easier to build a 500VA+40.000uF transformer+caps bank as a power source for the modules.

DIYing UCD amps with Hypex stuff is more like lego than pure DIY stuff - you'll just have to put everything together, just watch the cabling and layout recommendations a bit and you can't go wrong.

There's prebuilt amps also, but not from hypex.nl directly

Of interest when I Googled Mr. Putzeys: Bryston continues its crusade against Class D amplification in their company "newsletters," this time with an article by Bruno himself (http://www.bryston.ca/newsletters/74_files/vol7is4.html).

Kevin at DIYCable.com sells the Hypex amplifiers in kit form (http://www.diycable.com/main/product_info.php?products_id=599), and I was considering attempting to build one using a case from ATIResearch-Anodized, a Thai amp case manufacturer (http://www.atiresearch-anodized.com/products.html) . As someone who is not an EE and is pretty crappy with a soldering iron, I'm a little scared to attempt this, but it sure sounds intriguing.

Anyone willing to build me a 2-channel Hypex 400 to power my Ascend 340SE's? You could stick a logo on the case and we could add it to the OP as a new brand. See? I'm still on topic. ;-)

Best,
Adam

Adam haha :D

iirc http://www.effectiveaudiomod.com/ custom builds hypex-based amps to your spec. (look for the link below the Amp customizing service, US$1 = S$1.6)

Ad-Rok,

That's taken out of context: Bruno thinks digitally controlled class-d is a dead-end street.

His own baby, UCD, is analog controlled - it's a switching amplifier all right, but it doesn't take a digital signal in, it's purely analog, and the amp is self-oscillating, to fixed oscillator frequency.

If you get one to test it, please return here and post your findings... but I'm pretty sure you'll be happy :-)

Skip Taylor at D2Audio (http://www.d2audio.com/) is a big proponent of using DSP to pre-correct class D distortions and artifacts.

Ad-Rok,

That's taken out of context: Bruno thinks digitally controlled class-d is a dead-end street.

His own baby, UCD, is analog controlled - it's a switching amplifier all right, but it doesn't take a digital signal in, it's purely analog, and the amp is self-oscillating, to fixed oscillator frequency.

If you get one to test it, please return here and post your findings... but I'm pretty sure you'll be happy :-)

So I take it I'm not getting a signature Yves Smolders brand amp anytime soon, eh? Darn! Was hoping I'd rope you in. :D

Seriously, maybe the guys over at DIYAudio (or another thread here, but we don't have a DIY amp section...) could help ease my fears and walk me through this. It sure would be fun. I wish there was a step-by-step "lego manual" for building a 2-channel Hypex UcD400 amp. Who wants to write one? :-)

And you're right that was taken out of context. I don't see Bruno deliberately bashing his own product...I do see Bryston twisting his words into a Class-D bashing session though. Interesting stuff.

So when are you going to make my amp again? :-)

Cheers,
Adam

Skip Taylor at D2Audio (http://www.d2audio.com/) is a big proponent of using DSP to pre-correct class D distortions and artifacts.

Ah, so there are others working on this than ICEpower and Tripath. Doesn't look like D2Audio is poorly-funded, either, so maybe we'll see some promising developments out of them soon that will trickle down to the rest of the consumer home audio market.

Bob, you don't happen to have a spare one of these (http://www.qscaudio.com/products/amps/plx2/plx1104_specifications.htm) lying around needing, er... a beta tester? I could sacrifice myself and volunteer to test it out for you in my home theater. :D

Seriously, looks like you guys have done some interesting things with PWM amplification yourselves... have you considered marketing to the consumer home theater crowd?

Best,
Adam

Hi Adam,

Right now, the only PWM amplifier we offer is the power module for the MD Series powered loudspeakers. There will be more, but they're many months off still.

Of course... A well designed SMPS is very costly - much easier to build a 500VA+40.000uF transformer+caps bank as a power source for the modules.

depending on how you define "well designed". in general, it is tough to get a smps to work well for dynamic loads, in this case a class B or class D amp. the feedback loop inside of a smps complicates things many many times.

the conventional (unregulated) power supply, on the other hand, is simply much simpler but may be more costly solution.

Conceptually, a smps that can deal with a dynamic load is nothing short of a class D amp itself.

Seriously, maybe the guys over at DIYAudio (or another thread here, but we don't have a DIY amp section...) could help ease my fears and walk me through this. It sure would be fun. I wish there was a step-by-step "lego manual" for building a 2-channel Hypex UcD400 amp. Who wants to write one? :-)
Cheers,
Adam

You don't really need a manual. The UCDs are pretty much plug and play, and the only soldering required is for wiring the outputs. Like you, I was very hesitant to assemble them myself, so I had DIY Cable build a two channel and a three channel UCD400AD for me. I recently upgraded the transformers when DIYC's new ones became available and I did the swap myself. There really wasn't much to it and now that I've seen the internals, I'm planning to build a four channel myself (using a predilled chassis from DIYC) to drive my subwoofer. I know absolutely nothing about electronics and wouldn't recognize a rectifier if it bit me on the arse. But I'm confident that I can put one together using the schematics on Hypex's and DIYC's websites If I can do it, anyone with an IQ slightly higher than that of the average turnip and hand-eye coordination only slightly above that of a chicken with polio should be able to do it as well. Trust me. :D

depending on how you define "well designed". in general, it is tough to get a smps to work well for dynamic loads, in this case a class B or class D amp. the feedback loop inside of a smps complicates things many many times.

the conventional (unregulated) power supply, on the other hand, is simply much simpler but may be more costly solution.

Conceptually, a smps that can deal with a dynamic load is nothing short of a class D amp itself.

Actually, our company is developing a multichannel amp for HTPCs using slightly modified UcD modules (btw, it's Universal Class-D) and SMPS (currently Resonant mode, but experimenting with alternatives). Also built into the amp is our own high-end multichannel soundcard. Basically, the soundcard section is connected to the HTPC via FireWire; the fully differential (balanced) analog outputs from the soundcard section are connected directly to the fully differential inputs of the modified UcDs (via high quality volume control chips). We are very pleased with how the resonant SMPS performs compared to the linear supplies we have used in the past.

-Gregg

conventional linear supplies

"Conventional" and "linear" do not go together. ;) Conventional supplies are still highly non-linear due to their use of peak rectification.

"Conventional" and "linear" do not go together. ;) Conventional supplies are still highly non-linear due to their use of peak rectification.

Ah... should of said "more common" or "traditional".

Ah... should of said "more common" or "traditional".

:cool:

We use resonant switching in our supplies, too; it greatly reduces emissions, as well as dissipation in the switching devices.

You can add the new NHT Power5 to the list of digital amps and ICE amplifiers. 5x200W ICE design for $2K - www.nhthifi.com They say they're coming out with a stereo amp (Power2?) as well.

A little bird whispered in my ear... The Hypex UCD line will soon see a Hypex 1000VA SMPS to match the amplifiers. Not sure if they will work for 180, 400 and 700, that remains to be seen...

A little bird whispered in my ear... The Hypex UCD line will soon see a Hypex 1000VA SMPS to match the amplifiers. Not sure if they will work for 180, 400 and 700, that remains to be seen...

Awesome news, Yves...will be interesting to see how that plays out.

Question to you and the group here and I apologize in advance for possible off-topic: does this look like an accurate parts list "per channel" for building a UcD-400 system?

Hypex UcD-400 Shopping List "Per Channel"
Hypex UCD-400 Module
Hypex UCD ST Power Supply
Hypex UCD400 1KVA Torroidal Transformer
Hypex SoftStart Module
Hypex UCD Input Cable
Exodus Binding Post
Exodus EX-FRCA RCA Connectors
(Cardas Shielded Cable for internal connections other than Hypex cable?)
(Some sort of output cable to the binding posts, and power cable from the AC outlet connector?)
(Chassis with AC power inputs?)

I suppose that if I manage to build one of these, I could slap a shiny anodized label on it, brand it and add it to the list of PWM amps above. :-)

BTW, as far as I can tell this parts list comes in under ~$450 at DIYCable.com, while CIAudio.com is selling their extremely highly-reviewed UcD400-based monoblocks for like $1400 apiece and I think they use identical components. Go figure.

Best,
Adam

Good luck to you! Whatever you do, take the 400AD modules - the opamp is so much cleaner.

1 KVA toroid is a lot, in that case I'd use the advanced power supply as well. I've got 2 400AD's running off a single 500VA but with the better PS - 40.000uF instead of 20.000uF. Never heard it running out of steam (should be rock solid for 8 ohm loads)!

2 times 1KVA is overkill for sure. You'd need 2 softstarts for this as well I believe...

You'll be amazed how big a 500VA toroid is already... it's larger than most amps out there are using. Most receivers run less VA's in smaller caps, and that's for 7 channels...

If you're new to electronics... *watch out* - You're playing with dangerous things, worse than mains - DC power at voltages used in these amps are lethal without a doubt. 40.000uF of loaded caps will do the same if they release their energy to your body. Lastly, caps like this could explode violently if polarity is connected wrong. Check, check and check again... if you're not sure, let someone build it for you!

CIaudio is expensive indeed, but they don't use stock UcD's - they are tweaked on some crucial points, like the coupling caps for example.

Tweaks like that are on the verge of audiophile/audiophool though - sounds better? Yes probably. Sounds better enough to multiply the price by 3? Not really.

"Conventional" and "linear" do not go together. ;) Conventional supplies are still highly non-linear due to their use of peak rectification.

the "linear" comes from the regulation part of the power supply where the active device works in its linear regeion - between fully on and fully off to maintain the desired output levels.

it doesn't refer to the rectification part of the supply.

Good luck to you! Whatever you do, take the 400AD modules - the opamp is so much cleaner.

1 KVA toroid is a lot, in that case I'd use the advanced power supply as well. I've got 2 400AD's running off a single 500VA but with the better PS - 40.000uF instead of 20.000uF. Never heard it running out of steam (should be rock solid for 8 ohm loads)!

2 times 1KVA is overkill for sure. You'd need 2 softstarts for this as well I believe...

You'll be amazed how big a 500VA toroid is already... it's larger than most amps out there are using. Most receivers run less VA's in smaller caps, and that's for 7 channels...

Thanks much for the tips! I'll go 400AD for sure. What parts do you think would make sense for a 3-channel configuration in terms of toroids, power supplies, and other parts? I think the HG power supply sounds like a must.

I've also read about some RFI interference; would I need something to reduce that or does that depend on proper chassis/case selection?


If you're new to electronics... *watch out* - You're playing with dangerous things, worse than mains - DC power at voltages used in these amps are lethal without a doubt. 40.000uF of loaded caps will do the same if they release their energy to your body. Lastly, caps like this could explode violently if polarity is connected wrong. Check, check and check again... if you're not sure, let someone build it for you!

I'm definitely not sure...so perhaps I will ask someone to build. I have soldered before (not with much skill) and am certainly not new to electronic component wiring, but never amps...

Best,
Adam

the "linear" comes from the regulation part of the power supply where the active device works in its linear regeion - between fully on and fully off to maintain the desired output levels.

it doesn't refer to the rectification part of the supply.

What he mentioned were "conventional linear supplies," which is an oxymoron because any supply that uses peak rectification, as a conventional supply or even a switch-mode supply that has a rectifier feeding a capacitive reservoir, is not at all linear. Instead, it is quite non-linear, with little or no conduction except at the AC voltage waveform peaks. No one made any mention of regulation.

No one made any mention of regulation.

you don't have to mention any and everything in a conversation. Or we will not be able to have one at all.

case in point: you don't hear people say that they have a non-linear switching mode power supply, or a non-linear conventional power supply.

FWIW, I have Ascends, and have been using the NuForce Ref8b class D amps...and have been very happy.

That said, I just bought a "Beast" from Bertram. A two channel 500wpc amp using two ICEpower 1000ASP modules.

I heard the Bel Canto e.One Ref1000, which uses the same module and was very impressed before I even knew what it was.

cschang,

Do you notice a difference in your new amp compared to the NuForce ?

Regards,
Jose

cschang,

Do you notice a difference in your new amp compared to the NuForce ?

Regards,
Jose
I won't have it for a couple of weeks.....it is currently in route to me.

you don't have to mention any and everything in a conversation. Or we will not be able to have one at all.

case in point: you don't hear people say that they have a non-linear switching mode power supply, or a non-linear conventional power supply.

No, but many people mistakenly believe that conventional power supplies are linear, whether or not they are regulated. Typically, when someone says "linear supply," he or she is not referring to regulation but is using a misnomer.

Typically, when someone says "linear supply," he or she is not referring to regulation but is using a misnomer.

I don't know about that. I would say that most people (I run into) use "power supplies" to mean unregulated power supplies, and linear supplies to mean "regulated power supplies".

and think about it, there is a "linear" element in a switching mode power supply as well. so it is hard, if not outright impossible, to be 100% precise.

IME, regulated supplies are referred to as "regulated supplies."

IME, regulated supplies are referred to as "regulated supplies."

you are absolutely correct, in your opinion.

Unfortunately, the world doesn't revolve around either one of us. Just as nobody calls rectified power supplies as "non-linear power supplies"

you are absolutely correct, in your opinion.

Unfortunately, the world doesn't revolve around either one of us. Just as nobody calls rectified power supplies as "non-linear power supplies"

Don't worry, I'm fully aware of that. I've seen plenty of conventional, unregulated supplies incorrectly referred to as "linear."

Yet another forum to keep track of........

I noticed several hits coming from this site, so I decided to register in order to answer any questions that you may have.

You can ask on the the forum, or send an e-mail.

(Can't say I care for the color scheme, but I like some of the ways it operates. Especially the "no links in the sig" part. One of my pet peeves. Plus a spell check. I'm impressed.)

Pat
Analog Research-Technology

Pat, use the alternative color scheme. its grey background with blue/indigo accents - much better than the black bg

p.s welcome on here :)

ar-T, this is (by far) one of the largest forums out there... welcome :)

Actually, our company is developing a multichannel amp for HTPCs using slightly modified UcD modules (btw, it's Universal Class-D) and SMPS (currently Resonant mode, but experimenting with alternatives). Also built into the amp is our own high-end multichannel soundcard. Basically, the soundcard section is connected to the HTPC via FireWire; the fully differential (balanced) analog outputs from the soundcard section are connected directly to the fully differential inputs of the modified UcDs (via high quality volume control chips). We are very pleased with how the resonant SMPS performs compared to the linear supplies we have used in the past.

-Gregg

So, are you saying your product will replace both my soundcard and receiver/amplifier?

So, are you saying your product will replace both my soundcard and receiver/amplifier?

Neat! I hope the soundcard can playback 16-bit 44khz without altering the stream, like most soundcards do...

NuVo Technologies P2100 (http://www.nuvotechnologies.com/prozone/nv_p2100.htm)

http://www.partsexpress.com/images/300-848m.jpg

So, are you saying your product will replace both my soundcard and receiver/amplifier?

Yes, that's right. Our product basically has a high quality external soundcard built in. The balanced outputs from the analog stage connect directly to the Class-D amp modules. However, the performance specs are much higher than most consumer soundcards.

Neat! I hope the soundcard can playback 16-bit 44khz without altering the stream, like most soundcards do...

That shouldn't be a problem since we have ASIO drivers. With our current prototype we can play 16-bit 44.1kHz audio unaltered with applications that recognize the ASIO drivers.

Interesting post by Bruno Putzeys over at Audioholics this morning:
http://forums.audioholics.com/forums/showpost.php?p=189175&postcount=26

MY ICEpower 1000asp based amp arrived yesterday!

Interesting post by Bruno Putzeys over at Audioholics this morning:
http://forums.audioholics.com/forums/showpost.php?p=189175&postcount=26

it is just silly to see people fight this much over nothing.

Interesting post by Bruno Putzeys over at Audioholics this morning:
http://forums.audioholics.com/forums/showpost.php?p=189175&postcount=26

MY ICEpower 1000asp based amp arrived yesterday!

Keep us posted on how it sounds Curtis. I'll keep you all posted on my UcD adventures should you care to read about them, probably in another thread once I take the plunge and buy the parts. Thanks to Yves and all for guidance.

Poor Bruno...he should never have put his personal e-mail address at the bottom of that audioholics article! :D

-Adam

Keep us posted on how it sounds Curtis. I'll keep you all posted on my UcD adventures should you care to read about them, probably in another thread once I take the plunge and buy the parts. Thanks to Yves and all for guidance.

Poor Bruno...he should never have put his personal e-mail address at the bottom of that audioholics article! :D

-Adam
Sure thing Adam.

Would love to compare a UcD400 and 1000asp based amps.

it is just silly to see people fight this much over nothing.

Fighting???? I don't see how you came to that conclusion.


BTW.........don't hook your ASP1000 up to anything lower than 4 ohms. Yes, it will drive a lower impedance, but I don't think you will like the results. Especially true if you are comparing directly to a UcD 400.

Trust me.......I know these things.

Pat

BTW.........don't hook your ASP1000 up to anything lower than 4 ohms. Yes, it will drive a lower impedance, but I don't think you will like the results. Especially true if you are comparing directly to a UcD 400.

Trust me.......I know these things.

Pat
Thanks for the tip.....and I don't plan on hooking them up to anything under 4 ohms.

How do you feel about them above 4ohms? Right now, it sounds great!

Fighting???? I don't see how you came to that conclusion.


BTW.........don't hook your ASP1000 up to anything lower than 4 ohms. Yes, it will drive a lower impedance, but I don't think you will like the results. Especially true if you are comparing directly to a UcD 400.

Trust me.......I know these things.

Pat

Did you compare the Ice to the UcD? I asked someone who tested the Ice module and then looked at the Hypex information. He told me he preferred the Hypex design concept to the Ice.

There are a lot of opinions out there. I asked a couple of people the same question and got different reactions.

There are things that I like about both ICEpower and Hypex. For the most part, I view them as interchangeable. The main factor being the intended application.

The load dependent nature of the ICEpower is the main drawback, and it is not the same for all 3 power versions. The 1000 being the most load dependent. As they were originally intended for powered loudspeaker system, it may not be fair to call it a design shortcoming. It is frustrating that a module capable of delivering 1000 W would turn out to be less than optimum for low-Z, low-efficiency speakers. However, in fairness, I believe it was intended mainly for woofers and sub0woofers, and not full-range speakers that are a difficult load to drive. (The stand-alone version is only rated to 6 kHz; that ought to be a good clue.)

I think both ICEpower and Hypex are an excellent choice for HT systems. For high-end 2-channel systems..............system matching becomes more critical, as the customer has different expectation levels. Whether they are realistic or not.......that is a subject best left to audiophile forums.

Where my input is usually received in a less than welcome manner.

20+ years of dealing with neurotic audiophiles has a way of wearing on your nerves. Even for someone like me who has audiophile leanings. We would like to concentrate more on the HT market, but our roots run deep in conventional 2-channel systems. Change is not easy, especially for a bunch of cranky old engineers.

Pat

Audiophiles are a weird crowd indeed - I'd see myself more like a hifi-nut, not audiophile.

My dream was to buy N804 speakers, because I really like the way they sound. and finally I did buy them after a long long wait...

Now you can choose for yourself if these speakers are "high-end" or not, that depends on your wallet I guess ( :D ), but for me they are amazing sounding, and surely at the top of what I'd spend on speakers.

Problem was that I couldn't afford good amplification right away, I had to make do with my AVR, which had trouble to drive the N804's (not because the amp doesn't "sound" good, but pure electrical, N804's impendance is tricky)

I was happy to hear them on bryston, rotels, and other usual suspects but couldn't afford these.

Enter a DIY forum somewhere, where they are raving about Diy UCD amps - couldn't resist and dropped the cash, thinking I could use those amps for a second system I have here with old Philips speakers that can handle a lot of power.

Built it, tested it, sounds wonderful with the Philips... Couldn't resist trying them on the 804s... Never looked back, to my ears the speakers were alive just like in the shops where they are demo'ed with the above usual suspects.

Now why is UCD so good? I believe it's the feedback system - the load is included in the feedback and that way optimizes itself to whatever you connect to it (given enough clean power to work with) - other class-d designs have linearity changes due to the load connected - not the UCD's.

Secondary, these UcD's have a "linear" distortion, meaning the distortion isn't higher at high frequencies, like in a regular class AB. The result is very clean highs, even on speakers that are told to be very tiring & forward in the highs, like my N804's.

Couldn't be happier, really... everyone should at least take a listen

Of course, this might just be a my-kid-is-cuter-than-yours placebo effect... ;)

Value for money it's a no-brainer! and meanwhile... "audiophiles" are laughing because I run the precious B&W gems with "dirty class-d" power...

the feedback scheme in the ucd doesn't really "optimize" for the load, it just makes the load less of a factor for the output.

99.99% of the amps out on the market today has that 'featuer'.

TLF, you mean 99.99% of the amps out there include the speaker in the feedback loop?

Interesting.....I have read of people driving Apogees(ie. difficult load) with ICEpower and having great results.

99.99% of the amps out there incorporate speakers in its feedback loops in a fashion identical to that of the UcD.

hopefully it clarifies a bit more.

Have a look at these units:
www.coldamp.com
They have 400W @ 4 ohms modules, plus switching power supplies, which makes perfect sense to rid yourself of bulky and heavy linear ones...

UCD Feedback gives cleaner highs, like class AB amps? Did I read that right? I am an owner of ICE powered amps that are driving 1 ohm speakers. The highs cannot get any more pristine. :)

I did not say that you can not drive Apogees with ICEpower. The poster above is a good example that shows you can.

I did say that the ASP1000 is not a good choice, in spite of its power capabilities.

Remind me some day to measure the 500W ICEpower with a 1 ohm load. We only have data on the 1000W version into low-Z loads.

Pat

Pat, do you have any data on the UcD700 into 2ohms?

ar-t, you know who I am. I agree that the ICE1000 is not the best choice. I think you would agree best results can be had using the 500A.

Muralman, imho the UCD's outperform most regular class AB amps I've heard, except for the more expensive ones.

For what it's worth, listening experience is much easier on the ears using the UCD400's as external amps on a denon 4306 then using the internal 4306 amps.

I do of course realize that this Denon receiver isn't up there with for example Rotel 1080 or better.

Didn't do ABX or anything - a good indicator isn't sound quality per se, but listening fatigue - the internal amps were fatiguing my ears a lot quicker than where I am now.

I tend to go up on the volume more easily as well, but this might have nothing to do with class AB vs D - it's just that the UCD amp I've built has more capacitance and way more VA on the transformer than the Denon has!

There is one important thing owners of Class D amps come to realize, if they are lucky. That is, garbage in, garbage out applies like never before. Class D amps have very little character of their own. Being ruthlessly transparent is a double edged sword. More of the signal gets through unscathed, but at the same time, all that capacitance in connectors you hear about also broadcast an Alkaseltzer fizz. More damaging seemingly OK front ends are spotlighted like the lame ducks they are. Conventional amps give these bad characters a soft landing, so they are hardly noticed.

That's absolutely right. Dynamics are effortless. Combined with decent speakers it's a blessing and a curse!

Piano & womens voices are absolutely fantastic to hear on my system, if the recording is ok.

However there's a bad trend towards "hot mastering" or the "loudness race" you hear about. It used to be only for pop music, but it's made its way to all styles of music.

I've got a CD here called "My name is Larry", a new artist with an amazing voice. She does the light jazz genre a la Katie Melua.

The CD is unbearable. Everything is mixed into the top 5db of the CD range. Try to imagine what a piano sounds like if the dying reverbs are as loud as the attacks, and you hear the compressor pumping away with each strike of a note. The recording is *killed* - heard the voice clip here & there... mind you, the voice, not the odd bassdrum clipping...

It's amazing these days, if you pick a late 80's album and start playing it, you need to turn up the volume quite a bit... the dynamics you're getting are very rewarding however!

Being ruthlessly transparent is a double edged sword. ... all that capacitance in connectors you hear about also broadcast an Alkaseltzer fizz. ...Conventional amps give these bad characters a soft landing, so they are hardly noticed.

just where did you get all the above? Amazing, isn't it?

Yvez, I hear you! A listener flew 400 miles to hear my system. Everything was stellar with my own discs, until the fellow put on, "A bad disc." We had to turn the volume way up just to simulate some form of dynamics similar to what we had been listening to. The strain was audible.

tlf, When I moved from a well known top flight solid state amp to my present class D amps, I kept the same wires. Everything sounded better, after all.

I learned. First to go were the power cords. A TacT owner nearby brought over some shielded cords, and the change was real. Next, out went the speaker wires. Exotics like ceramic, magnet wire, and helical, formally I thought of as perhaps quacky, proved to be the real deal.

You have some good points. If not matched properly, Class D can sound awful. And I believe that leads to a lot of the negative impressions that people who have not heard them are convinced are gospel truth.

As for the -500 being the best........

Depends.

I prefer the -250. It is a bit smoother, and does not interact with the load as much as the -500. The -500 has more "oomph", and if you have speakers like my friend above does, then it is the only choice of the 3. I remain convinced that he has a synergistic effect in his system, where the anomalies of the amps and the speakers cancel each other out.

My system uses Maggies (the ones without the ribbons), and as a result, it gives more of a "tube-like" sound. Our customer base is heavily weighted towards Maggie owners, but most have ribbon tweeter versions. They seem to blend well with all types of planar speakers.

Cone driver speakers..............requires some tweaking to get it right. They are not "plug and play" on those speakers. One of our beta testers has WATT/Puppies, and they can be brutally revealing. I did mange to convince him to ditch his horrible sounding MIT speaker cables. Muddy, exaggerated bass, and rolled-off highs. (I hope Dave Wilson isn't reading this, as he remains convinced MIT is the only way to go. Yuk.)

The reason I brought them up is that you can really hear differences in soundstaging on them. Very subtle differences in frequency response can make major changes to imaging. Anything from wider than the room, to putting the singer right in your face. I prefer the former, most customers the latter, and the beta tester can not decide which he likes. Actually, he likes both, and wants both. We made a special version that allows him to switch between the two, and have plans to make it a standard feature.

The results have been mixed. Some love it, others think it is the dumbest thing we have ever done. Others think they like the idea, but are unconvinced we picked the right settings.

As for capacitance.........

A lot of users report that high-capacitance speaker cables suck all the life out of the sound. That observation seems to hold true regardless of what brand/topology of Class D amp.

As for the UcD700........

We have looked at any yet. Based on our tests with the -180 and -400, I would not expect any difference in FR based on load Z.

Pat

Agreed. No class D amp is a sure bet plopped down into a system. I knew I could make it work. Some people are lucky, and have a system that is compatible. Others want to dismiss the new technology out of hand, and are most pleased if they can make it fail. Certainly, using MIT is a proven way to assure failure.

First to go were the power cords. ... the change was real. Next, out went the speaker wires. Exotics like ceramic, magnet wire, and helical, formally I thought of as perhaps quacky, proved to be the real deal.

but you never used fully conditioned digital electrons did you? if you did, you would have thrown away anything you have bought. it is amazing how those little things can change the sound stage.

:)

Yes, we experiment with conditioners too. They are not the fixall they are made out to be. Some are current limiting. Others lasso high frequencies. All the others I mention do very special jobs, and do make a big difference, conditioner in line or not.

This is a digital/class-d amp thread people, not an esoteric audio equipment thread... :D ;)

Yves, our collective point is, digital/class D amps need carefully chosen components to not sound dull and lifeless.

If we were talking about tubes or solid state, I doubt the same system concerns would be shown.

If we were talking about tubes or solid state, I doubt the same system concerns would be shown.

HA! :D

:p the H2O Sig, when properly equipped, and with it's stable mate preamp, the Fire, Rocks big time!!!!!!!!!!!!!!!

"Yves, our collective point is, digital/class D amps need carefully chosen components to not sound dull and lifeless."

This is a digital/class-d amp thread people, not an esoteric audio equipment thread.

Yes, we experiment with conditioners too.

my experience with electron conditioners is that a) you have to make sure that they work on digital electrons; b) the correct spins make absolutely a huge difference. I have found 2.5 positive left spins help rendition of sound stage for classical music, but suck for rap; and 1.75 right spins, positive or negative, tend to be great for easy listening.

Of course, you will have to mate them with the right power cords, moon phase of the day and menopause cycles of the neighbor to your left.

:)

magnet wire is exotic?

magnet wire is exotic?

I think so. You have to admit, The use of naked magnet wire goes against the grain of a couple decades cable design theory. There is lots of room for .

I'm getting off this thread before someone starts to put stones on top of his class-d amp...

if you are using some of the thick wires on a nuForce or flying mole, you may need to put stones to weigh your amp down

The use of naked magnet wire goes against the grain of a couple decades cable design theory. There is lots of room for .

what grain does the naked magnet go against?

just curious.

I think so. You have to admit, The use of naked magnet wire goes against the grain of a couple decades cable design theory

Did you forget the sarcasm tag?

Do you realise that magnet wire is the same as copper wire? It's even insulated.

I'm getting off this thread before someone starts to put stones on top of his class-d amp...

Stones are so 1990s. Pyramids consisting of cryogenically treated crystals are where it's at. They systematically unstifle high frequencies stifled in power conditioners and power cords.

Did you forget the sarcasm tag?

Do you realise that magnet wire is the same as copper wire? It's even insulated.

Of course, only that thin lacquer coating is an insignificant dielectric. Also, there is this little tidbit I read off some transformer company white paper. The writer says what we are all use to hearing from every copper cable maker out there, that they use 99. yadayada % pure copper. A picture is show of stacks of raw copper sheets.

Now here is the heresy. The writer says, to promote better conductivity they "INFUSE an exacting amount of OXYGEN into the copper, before drawing the wire.

Now, I am not saying this is good or bad. It just shows there is more to making magnet wires that one may suppose.

I just installed fish ponds. I have this nifty jar of bacteria that keeps the water crystal clear. I am wondering, what if I inject some of this into the signal???????

what if I inject some of this into the signal???????

it would surprise if you got a huge fan following who would be foolish enough to buy into the claim of better sound stage, clearer highs and punchier bass.

audio is the modern equivalent of organized religion.

I just installed fish ponds. I have this nifty jar of bacteria that keeps the water crystal clear. I am wondering, what if I inject some of this into the signal???????
Then it just sound like a crystal? or clear as transparent, tree in the forest thing? :D

The writer says, to promote better conductivity they "INFUSE an exacting amount of OXYGEN into the copper, before drawing the wire.

Now, I am not saying this is good or bad. It just shows there is more to making magnet wires that one may suppose.

It shows, that one doesn't know what magnet wire is, and is looking for something, anything, to make magnet wire exotic.

[QUOTE=tlf9999]it would surprise if you got a huge fan following who would be foolish enough to buy into the claim of better sound stage, clearer highs and punchier bass.

I do have a following here, and they are not crazy. My sound, with the right material, is eerily real.

A recent forum quote from one of those fools: "The Audo Note was the clear winner. The other listener noted that we were listening to a MAN sing, not just vocals on the particular tracks we used for comparison. The Audio Note truly "fleshed out" the singer."

It shows, that one doesn't know what magnet wire is, and is looking for something, anything, to make magnet wire exotic.

Jees :rolleyes: Magnet wire is a simple thing. It was Paul Speltz who gave it a shot to use it as interconnects and speaker wire. Have you ever watched the PBS series, "Connections." Some accidental discoveries account for some of our biggest evolution of applied knowledge. I think the way magnet wire turned common thinking on ICs and SCs on it's head. I have yet to hear better mids.

"The Audo Note was the clear winner. The other listener noted that we were listening to a MAN sing, not just vocals on the particular tracks we used for comparison. The Audio Note truly "fleshed out" the singer."

and I am sure that listener's impression is truthful and accurate. Whether he heard what he heard remains to be seen.

my disappointment over the entire exchange is that after all these blahblahblah, we still don't know what grain the naked wire goes against in electronic theories. I guess when people are desparate in making something up (aka in a religion), they will make anything up.

Jees :rolleyes: Magnet wire is a simple thing.

Magnet wire is indeed a simple thing, since it is just copper wire with a lacquer insulation, which only makes it less convenient for non-magnetic applications than equivalent insulated copper wire.

and I am sure that listener's impression is truthful and accurate. Whether he heard what he heard remains to be seen.

my disappointment over the entire exchange is that after all these blahblahblah, we still don't know what grain the naked wire goes against in electronic theories. I guess when people are desparate in making something up (aka in a religion), they will make anything up.

Keeping the naked wire in context, it simply does not confuse detail as jacketed wires do. These things count when ultra resolving electronics, and speakers are listened to.

The Shunyata helical cables have better extension. This is do to their sophisticated coiling. It's in the mids where the magnet wire holds supreme.

This is do to their sophisticated coiling.

I am sure you can articulate how this "sophisticted coiling" helps it achieve that great performance.

It is OK to believe even the most outlandish things - that is what we have faith for.

It is NOT OK to fabricate scientific-sounding reasons to justify your believes - faith does not need any justification.

As I have stated, the difference between Ant-cables, and just about any heavily insulated cable is demonstrable. Try them out. They are cheap. Faith has nothing to do with it. This is not alchemy.

Here is another curve ball. I have heard ceramic interconnects, called Cerious. They replaced silver ICs on a friend's system.... They are simply AMAZING!

It's not the details that are confused. ;)

Jees Magnet wire is a simple thing.

Correct, it also called insulated copper wire...why is this so difficult to underestand?

Keeping the naked wire in context, it simply does not confuse detail as jacketed wires do.

Oh, I see why...

Semantics. The proof is in the listening. Shunyata's helical cables happen to go light on insulation as well. The least coating on a wire is the best. Dielectrics is a real demon to the pure signal.

I just installed fish ponds. I have this nifty jar of bacteria that keeps the water crystal clear. I am wondering, what if I inject some of this into the signal???????

actually, I would recommend injecting the bacteria direct into the speaker cone. Keep the cone warm and moist for the next few days by doing occasional spits on the cone surface, (that should attract addtional bacteria and helps the culture to grow). I now have a perfectly green moist cone that has the clearest transparent sound one can imagine. It beats any speakers in the price range of $100,000.

The best thing was if I needed some greens for my meals, I could scrap some off the cone and I could swear that it added PRAT to my beef steak. Of course, cooking my beef steak off my Naim amps must have helped in that area.

It's not the details that are confused. ;)

The electronics engineer designer of my amps was quick to change his mind when he tried out shielded power cables, and magnet wire.

that is a sure sign that you need a real and competent electronics engineer, :)

All of these comments about esoteric wire and cabling is beginning to ruin this thread. Can we please get back on topic and talk about PWM or Class-D amplifiers?

that is a sure sign that you need a real and competent electronics engineer, :)

One that designs robotics?

All of these comments about esoteric wire and cabling is beginning to ruin this thread. Can we please get back on topic and talk about PWM or Class-D amplifiers?

I would not call improvement discussions ruining a class D thread. Most of this thread has been spent arguing about what's digital, and what's not. B&O state clearly in their white papers their ICE modules are analogue.

Their most useful model to the amp builder is the 500A. Two things set this module apart from all B&O's ASP modules. First, they measure out better. Second, they require an add on power supply, which leaves the door open to talented amp engineers to create a product quite different than what the module in the box builders.

B&O has improved their 500A module. I find that hard to believe, but just the same, I am having my amps upgraded.

The least coating on a wire is the best. Dielectrics is a real demon to the pure signal.

Care to explain why?

(this ought to be good)

One that designs robotics?

one that is competent and understands electronics.

Care to explain why?

(this ought to be good)

Speltz charges $1 per foot. See for yourself. What have you got to loose? http://www.anticables.com/testimonials.html

Speltz charges $1 per foot. See for yourself. What have you got to loose? http://www.anticables.com/testimonials.html

Anticable: $1.
Naked copper wires: $10.
Listner impressions: $1,000.
Getting muralman to substantiate his conclusions: priceless.

Please add this piece to the list, it includes a 5 channel digital module with patent pending technology.

http://revox.ch/images/c_p_resystem_m51.jpg


REVOX M-51 (http://revox.ch/content_bg.tpl?iid=l103a1b10c2d4e3f36&lang=2&iid2=11)

that is a sure sign that you need a real and competent electronics engineer, :)

Indeed.

Please add this piece to the list, it includes a 5 channel digital module with patent pending technology.

REVOX M-51 (http://revox.ch/content_bg.tpl?iid=l103a1b10c2d4e3f36&lang=2&iid2=11)

Nice, but I think it belongs in Grayson73's digital receiver (http://www.avsforum.com/avs-vb/showthread.php?t=417894) listing instead - together with the naim n-Vi

Nice, but I think it belongs in Grayson73's digital receiver (http://www.avsforum.com/avs-vb/showthread.php?t=417894) listing instead - together with the naim n-Vi
Agreed. But I got to admit, after a quick glance over what it is, it seems pretty cool!

Anticable: $1.
Naked copper wires: $10.
Listner impressions: $1,000.
Getting muralman to substantiate his conclusions: priceless.


The theory is, electrons are captured in wraps, to be rereleased into the wire randomly, causing distortion. The question is, what if the heavy insulation is removed? In science, we test the hypothesis to reach a conclusion. Like reported in the testimonials I gave you, I did that test, and I gave you my conclusion. End of story. Test for yourself, if you think I am not telling the truth.

one that is competent and understands electronics.

The designer of the H2O is an electronics engineer by trade, and brilliant amp designer by vocation. As an engineer, he is a conservative when it comes to unsubstantiated claims. What he found is, fully shielded cords bring out the best in class D, and digital amps. That find matches our testing of such cords on TacT and ICE amps.

The theory is, electrons are captured in wraps,

first of all, you need to tell us what "wraps" you are talking about here. is it wheet or multi-grain, or something else?

2ndly, get a basic college level physics book and try to understand how signals are transmitted. a hint for you: electrons travel at about a few centimeters a second in a copper wire. And ask yourself if that changes your understanding of the above "explanation".

to be rereleased into the wire randomly, causing distortion.

just where did you get this 'exotic' understanding of the laws of physics?

Like reported in the testimonials I gave you,

religions are built on testimonials. Sicence on the other hand is built on facts, and logic.

BTW, what amps did you make? I will make a note of avoiding it at all costs.

first of all, you need to tell us what "wraps" you are talking about here. is it wheet or multi-grain, or something else?

2ndly, get a basic college level physics book and try to understand how signals are transmitted. a hint for you: electrons travel at about a few centimeters a second in a copper wire. And ask yourself if that changes your understanding of the above "explanation".



just where did you get this 'exotic' understanding of the laws of physics?



religions are built on testimonials. Sicence on the other hand is built on facts, and logic.

BTW, what amps did you make? I will make a note of avoiding it at all costs.


First of all, I am talking about any "insulation" thicker than a coat of lacquer. That should have been self evident.

Secondly, I never said I build amps.

Religion cannot be substantiated through testing. That is why religion had to get out of the way of scientists throughout history, as understanding of natural law supplanted old myths.

Scientific theory is supported by testing. The results of that testing is published. Other scientists are expected to retest the the theory.

Are you denying capacitance exists, or are you saying it doesn't matter?

Are you denying capacitance exists, or are you saying it doesn't matter?

Third choice: neither.

What you described isn't capacitance. If it actually occurs, it's a new phenomenon and could win you a Nobel Prize if you document it well.

"In science, we test the hypothesis to reach a conclusion. Like reported in the testimonials I gave you, I did that test, and I gave you my conclusion. End of story. Test for yourself, if you think I am not telling the truth."

Scientific tests are verifiable and repeatable. Yours are purely your personal subjective impressions, are they not?

Get same results with blind testing and then you'll have something.

Are you denying capacitance exists, or are you saying it doesn't matter?

actually I was trying to get you to understand that the mechanism of signal transmission you proposed isn't really what happens: electrons do not transmit the signal, or we would have some really serious delays.

I was hoping you could spot the logical holes in your argument.