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List of PWM Amplifiers. - Page 2

post #31 of 357
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,
post #32 of 357
Noah,

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

Best,
post #33 of 357
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.
post #34 of 357
Quote:
Originally Posted by lej1447 View 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.
post #35 of 357
Quote:
Originally Posted by lej1447 View 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.

Some reading:

http://www.hometheaterhifi.com/volum...assOfOperation

and this one includes information on Class D:

http://www.extron.com/company/archiv...&version=print
post #36 of 357
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.
post #37 of 357
Thread Starter 
Quote:
Originally Posted by John Kotches View Post

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
post #38 of 357
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.

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




...
post #39 of 357
These are using UcD aplification:

Van Medevoort MA240

CIAudio D-100

CIAudio D-200
post #40 of 357
Thread Starter 
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



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

CIAudio is already there
post #41 of 357
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

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.
post #42 of 357
Thread Starter 

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?
post #43 of 357
I agree. Keep out the proamps out of the mix. Out with the old, in with the new. (and much more cool looking amps).


...
post #44 of 357
That reminds me of my old departed Sansui.


...
post #45 of 357
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....
post #46 of 357
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.
post #47 of 357
I've mentioned Adire Audio a few times on this forum, didn't do it in this thread though.
post #48 of 357
Thread Starter 
meanwhile I think this Saturday I'll go take a look/listen to the sneak peek of the new little 'Mole



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
post #49 of 357
Thread Starter 
Quote:
Originally Posted by John Kotches View Post

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-re...irtu-09-05.htm
post #50 of 357
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."
post #51 of 357
Thread Starter 
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
post #52 of 357
Quote:
Originally Posted by Bob Lee (QSC) View Post

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 like the UcD...
post #53 of 357
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,
post #54 of 357
John, on a sidenote, how's the multichannel UcD test coming along?
post #55 of 357
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,
post #56 of 357
Quote:
Originally Posted by Bob Lee (QSC) View Post

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..
post #57 of 357
I'm still pushing the term Pulsing Amplifier

John, if possible, please PM me with the information about this online publication of the test, thanks!
post #58 of 357
Thread Starter 
might be fun to conduct a scientific poll *LOL*
post #59 of 357
Bob Lee,

Thank you!






...
post #60 of 357
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.
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