or Connect
AVS › AVS Forum › Audio › CD Players & Dedicated Music Transports › Berkeley Audio Alpha DAC
New Posts  All Forums:Forum Nav:

Berkeley Audio Alpha DAC - Page 3

post #61 of 224
Quote:
Originally Posted by JorgeLopez11 View Post
There are some serious tests reported in the matrixhifi site that were carried following a scientific protocol

Denon DCD-920 VS dCS Verdi-LaScala VS dCs Delius:

http://www.matrixhifi.com/pc_scala_denon.htm

Results: NO differences
Typical matrixhifi listening conditions?



Harman's just wasting money. Still waiting for a statistically significant, peer-reviewed test showing audible/no audible differences in outboard DACs. Until such time, general conclusions are unwise.
post #62 of 224
Quote:
Originally Posted by RUR View Post
Still waiting for a statistically significant, peer-reviewed test showing audible/no audible differences in outboard DACs. Until such time, general conclusions are unwise.
You'll be waiting a long time, it's doubtful that anyone with the time, setup, and funding would ever approach the issue that way.

You can simply characterize the output of both DACs, make a list of differences, and look up studies that have been conducted to understand human hearing and perception of those differences. e.g. the DAC has +- 0.5dB ripple from 1 to 22khz, 120dB SNR, and < 0.05% THD+N over the pass band and 500ohm output impedance. Now read studies on the audibility of each parameter and compare the audible difference between both DACs.
post #63 of 224
Quote:
Originally Posted by xianthax
You can however prove that such a person exits, by finding them, which has never occurred in any attempted study i've seen.
Xianthax, take a look at the third reference of my previous post. It shows a test where differences do exist in a DBT test.

I just want to mention that it compared an expensive Audionote tube DAC VS a cheap Sony discman.

It seems tubes print it's own typical character to the Audiionote's sound...

Quote:
Originally Posted by RUR
Typical matrixhifi listening conditions?
And your point is?

If you have doubts about the acoustics of the listening room, here's the document that certifies those conditions:

Unfortunately it's in spanish language.

Additional note: the two gentleman at both sides of the image are not the judges. The judges are the three persons in the middle of the picture.
post #64 of 224
Quote:
Originally Posted by CDLehner View Post
I mean I really think Xianthax is suggesting...with a straight face...that I take online courses from MIT in order to choose gear correctly? I mean, I'm not misinterpreting him, right? Because I've been accused of that before.
You asked for proof, i told you were to find it. No where did i say you need to have a degree to select gear. Most moderately rational people accept the results of hundreds of years of study without working it all out to check for themselves, you don't appear to fit in this category.
post #65 of 224
I don't recall anyone in this thread saying they've actually bought this particular DAC from Berkeley and evaluated it in the confines of their home. CDLehner has previously stated that when he evaluates a product for purchase, he listens to it. However, it does not appear, WRT DAC's at least, that he applies critical level matching and some sort of blind testing to aid in his purchasing decision. Indeed, without knowing some of the products he's brought in, the absolute need for this sort of approach may not necessarily be warranted. Regardless, he's been fairly transparent in recounting his approach and in my rereading of this thread has not really tried to impose his methodology upon the world. In fact, he's been rather nice about the whole thing and I don't think he deserves to be pilloried for his view. If his present DAC - an EE tube DAC -puts a little fuzz or whatever on the songs and this makes the experience more enjoyable even if it's not 100% faithful to what's on the disc, so phucking what? More interesting to me at least would be to understand what it is that his DAC is doing. A link to the product page might be useful in getting a feel for what is happening to the signal.

WRT the DAC in this thread, it's of some interest to me as to what's going on with all those filters. The website is largely devoid of details. Yet, some may recall that several years ago the filter/spline game was played by both Wadia, Pioneer and Sony (overseas mostly due to patent issues) and this creates aliasing effects that often are audible. It's rather a pity that Berkeley doesn't say much or that there's no inside view of what's under the cover.
post #66 of 224
Quote:
Originally Posted by JorgeLopez11 View Post
Xianthax, take a look at the third reference of my previous post. It shows a test where differences do exist in a DBT test.

I just want to mention that it compared an expensive Audionote tube DAC VS a cheap Sony discman.

It seems tubes print it's own typical character to the Audiionote's sound...
Not at all surprising however it should be noted that the Audio Note has an additional analog output filter/driver so the comparison isn't really true to the 'different DAC' argument. That is your not comparing DAC performance anymore but comparing the performance of a Tube filter stage vs a solid state design.

Tube's do have a characteristic distortion profile no problem believing that many tube designs are audibly different from solid state designs. In addition their PSB layout is crap, looks like they etched it their basement. I'd be really interested to know the overall performance of the device, image into not very good.

How much do they charge for that thing? The actual DAC in it is a AD1865 which is not exactly a high end part. It out of production but its replacement with almost identical specs runs $4.71 each in lots of 1000.
post #67 of 224
Quote:
Originally Posted by Chu Gai View Post
WRT the DAC in this thread, it's of some interest to me as to what's going on with all those filters. The website is largely devoid of details. Yet, some may recall that several years ago the filter/spline game was played by both Wadia, Pioneer and Sony (overseas mostly due to patent issues) and this creates aliasing effects that often are audible. It's rather a pity that Berkeley doesn't say much or that there's no inside view of what's under the cover.
Very valid point, given the specs, the "firmware upgradeable", and the HDCP support its reasonable to think that this device isn't just a DAC but has a DSP doing some work on the audio before feeding the DAC. Pretty much kills any point in comparing it to an actual DAC when you have no idea whats going on in the DSP.
post #68 of 224
I couldn't think of a word other than 'fuzz' CDLehner when writing but I didn't mean to use the term as it may be by professional musicians using tube equipment. Thanks for the 6moons link. Seems that the device has quite a high output impedance and by virtue of that alone I'd expect audible consequences. I'll leave it to you to research what happens when the output impedance of a device is not small compared to the input impedance of what it's plugged in to.

As to the AudioNote product mentioned earlier, keep in mind that they have been known to make NOS (non over sampling) products and those have oodles of artifacts.
post #69 of 224
Quote:
Originally Posted by CDLehner View Post
But it's a special kind of arrogance to treat people like they're stupid, just because they didn't study your field. Maybe they were busy with Medicine, IT, or the like.
You really think it has anything to do with your field of study?

I sure hope your never tasked with setting up verification or test procedures in medicine, IT, or 'insert field of study'. Just ask the server what it thinks of its intrusion test, i'm sure it will tell you more than the logs.

Quote:
Originally Posted by CDLehner View Post
I'd love to hear what you EE types see.
Its an ESS Technologies DAC, most likely the ES9012 given the package and specs. Never heard of the company but the specs on the DAC are great, assuming its well implemented it should perform very well. The lack of supply decoupling and use of through hole components in the digital section is odd and will increase EMI emissions, i would assume it passed FCC part 15 so no big deal there assuming its not creating issues in the rest of the circuit (noise, instability). The pulse common-mode choke near the digital input may be a sign that EMI was an issue in the design.

The reconstruction filters and SS output drivers look to be implemented with TI opamps, NE5532/4P from the article text. Standard low noise op amps, surprised they didn't use burr brown or AD parts made for audio. This stage looks ok, quality caps, etc. The layout sucks, lots of places for noise pick up, little to no guarding of opamp pins and minimal supply decoupling. Hard to say more without a detailed look or schematic and PCB stack up. The tube filter at the bottom is the only thing i would expect to induce any audible difference vs a similarly spec'd DAC and it is not part of the DAC circuit but a post filter.

I wouldn't say there is anything terrible in the design, however the analog output sections are not well designed. The ESS DAC has some pretty impressive specs and at least according to the 6moons article the SNR on the solid state path is only 95dB and 90dB on the tube path.

Basically he used a 32bit DAC with up to 135dB of dynamic range and managed to come out with the SNR closer to what you would expect out of a CD player headphone jack.

So in summary, i would expect this to sound the same as anything with similar specs with the tube section disengaged. Considering the 95dB SNR just about any DAC would have the same or better specs.
post #70 of 224
Quote:
Originally Posted by CDLehner View Post

Not to ask for a crash course in EE, but can you give me the "gist" of what usually happens with such a combination? Not sure if I can find the input impedance of my power amp, as it's an older model. IYO, what is the sonic consequence of a high output impedance device?

CD

Among other things a voltage drop is created. For that DAC the output impedance is 10k with the solid state line driver and 22k with the tube output.

Amp input impedance can vary quite a bit, for some random numbers the rotel 1582 is spec'd at 32kohm. If that DAC was in tube mode and plugged into it the actual signal the rotel amp would see is about 60% of the output of the DAC.
post #71 of 224
Quote:
Originally Posted by CDLehner View Post

It's a 9018 actually. I also noted, even before the purchase, that the unit only manages to squeeze 90/95db of DR out of the highly capable 9018 chip. But I guess this is yet another one of those instances where I chose to trust my ears, rather than the specs.

I'm not disinterested in specs; nor discount them. But I bet in your DBTs, you can't tell a DAC capable of 95db versus one capable of 135db...so you're kind of taking both sides of the argument now. On the one hand, you say "all DACs sound the same in DBTs"; on the other, you're like "your DAC only gets 95db out of that chip".

SNR and Dynamic Range aren't directly comparable and its probably my fault for making sound that way. That is i wasn't saying that because the IC was rated at 135dB of dynamic range that the SNR needs or should be 135dB.

Point was that achieving 129dB (as its rated) of dynamic range with line level output and an SNR 90dB is unlikely to be useful. The noise floor at line level and realistic sensitivities for the next component in line would likely not allow that dynamic range to be used.

I saw that they stated is was a 9018 which i assumed was a mistake as that is a 8 channel DAC, the 9012 is the 2 channel variant in the same family. Quite possible tho, wouldn't be the first time a chip was chosen with a ton of unused features due to supply issues or similar.

Didn't really follow the rest of your post, you specifically asked for an EE's opinion of the design, thats what I gave you, why get all mad and imply arguments when you got exactly what you asked for?
post #72 of 224
Thread Starter 
Chu,

Michael Ritter and his associate [ I will get the name latter ] helped Pacific Micronics and Sony with HDCP as I recall. I can get more specifics because I know if I mistate, misspell, fart or burp you boys will be all over me.

I suggest you guys go to CES and take say 2-3 days and visit the audio rooms. Most are just bunk but there are some very worthwhile vendors to consider. No I do not own a unit in the sense of having installed in my system but I do have one brand new in a box ready to go for one of you highrollers

The M-Audio appears to be a splitter of sorts that would allow an instrument to go to both the main mixboard and sub board for recording using a digital connection. I am awaiting a reply from them it should be interesting.

As far as Berkeley rebadging a Lynx I cannot say. I do know that Berkeley suggest the LYNX audio card for home brew music servers. Did I say music server? Yes I did. To me this is the prime application of an outboard DAC imho.

In fact since you brought this up many companies manufacture off shore or use similar if not exact platforms. Audio Control [cut thier teeth in audio analyzers and 12V audio] and Arcam are the same surround processor preamp. Many amp companies use the the same modules especially in the Class D camp. Many speakers use ScanSpeak, SEAS, Focal drivers. Even the once might McIntosh rebadges some Denon and Escient products.

I wished you guys lived closer I would really love to bring a BAD to your home.
CDL lives close [withen an hour] so maybe he might be the test bed. He is a value oriented guy it appears [just follow his post in various forums here on AVS] and I think would say if it is better that the other DACs he has tried. Now if it is better one may still not want to pay for the price tag. If you look at my post this hobby is a N O T a linear format. I must say the Wilson Maxx III is better than my old Klipsch Cornwalls but not 25-30x better MSRP vs. MSRP.

Many of you have questioned CDL, RUR and myself [and others] about this or that. So now I ask you, ever listen to or install a Berkeley, EMM Labs, dCs, Esoteric, Apogee, Prism DAC? If not how can you say we [that have] are wrong? I am not saying your wrong and I'm trying my best to be polite and professional when it looks like some of you frankly just want to fight to show off your knowledge or what think is your superior intellect.

For me I just want to talk audio and learn as much as I can. I found the Berkeley to have a cost effective product to compare and compete against some of those I mentioned. Who knows I will be the first to admit if a $200 box is better. Trust me. In my HT I run Tannoy Pro install products with Audio Control electronics [if I move the demo system I might just go back to pro style amps, Face Audio - google them]. I listened to Tannoy and LapGruppen at a CEDIA 4 yrs ago and they run toe to toe [to me] with Genelec and JBL Synthesis for a third of the cost!

So if there is a better mousetrap I'm all for it. All I ask is do not insight riot and bully yourself around.
post #73 of 224
Quote:
Originally Posted by CDLehner View Post

Actually, I think I was able to find my input impedance...and it looks like it's 100kohm. So, am I "OK"?

CD

yea not that big a deal, drop won't be large enough to matter. The DAC's specs would claim it can drive past both consumer and pro definitions for "line level" anyway, although some devices/amps accept higher input swings.
post #74 of 224
Quote:
Originally Posted by CDLehner View Post

But there's only so many hours in the day, and so much expertise I can squeeze into this head. Between my job, and family...who has time for online classes at MIT?

You can at least read up on the term "colored sound" and "distorted sound" because those two are not the same.

Quote:


But I don't think I'd feel very welcome if your attitude was "you're a stupid a**hole, because you overpaid for your piece-of-sh*t gear".

It's a public forum. When replies are made, it's not just for you (otherwise PM will be used), there are lurkers reading and learning from places like this. I know because I've been one of them. Same is true for what you post. Those who feel the need to challenge certain posts will do so in an attempt to let others (not just the one who he is replying to) be aware what ought to be called out. Others learning about what is overpriced and what isn't, is not a bad thing. Sure, some feelings may get hurt but that's what goes on on internet forums. This ain't no namby-pamby land.

Quote:


Fellas, you don't give two, hot sh*ts what I have to say; and from the PMs I've been getting, I can't hope to change your minds or attitudes...but I'll try anyway. Can you maybe ease up on the high-ground just a little? I mean, if I can agree to walk away, thinking a little more about what I'm really getting for my money...and to think about what's under the hood...can you maybe walk away thinking a little more about how people are entitled to buy what they like, and that maybe it's not your place to turn your nose down at them?

Not all internet forums are the same. Some forum leans to certain way than others. The key is to find the one you like and stay there. I don't go to Audio Asylum and try to change the way they are. vvv
Quote:
Originally Posted by CDLehner View Post

Mostly what I was doing is trying to turn back the tide of this "all DACs sound the same" sentiment.
post #75 of 224
Quote:
Originally Posted by mmiles View Post

As far as Berkeley rebadging a Lynx I cannot say. I do know that Berkeley suggest the LYNX audio card for home brew music servers. Did I say music server? Yes I did. To me this is the prime application of an outboard DAC imho.

Yep, i use a DAC for this, motherboard sound cards are usually quite bad, not surprising given the environment and lack of space. M-audio fast track Pro work quite well, $175.
post #76 of 224
Quote:
Originally Posted by mmiles View Post

I wished you guys lived closer I would really love to bring a BAD to your home.

Wouldn't you say if BA does a level matched DBT carried out by an independent party (to silence the critics) and beat out their competitors, would make an amazing sales pitch, no? I would say so. They should try it. Or maybe they already did.
post #77 of 224
Quote:
Originally Posted by mmiles View Post

Michael Ritter and his associate [ I will get the name latter ] helped Pacific Micronics and Sony with HDCP as I recall. I can get more specifics because I know if I mistate, misspell, fart or burp you boys will be all over me....

Keith O. Johnson and Michael "Pflash" Pflaumer are the inventors of HDCD. Johnson, Pflaumer, Ritter, Rene Jaeger and others collaborated at Pacific Microsonics on the PM Model 2 DAC. Ritter, Pflaumer and Jaeger are principals @ Berkeley; multi-Grammy award winning Johnson continues to design Spectral gear and to produce albums as Technical Director, Recording Engineer and partner at Reference Recordings.
post #78 of 224
Quote:
Originally Posted by geekhd View Post

Here you go CDLehner. These are repost.

Comparison of DAC in $9,380 CD player vs DAC of $175 DVD player.

$900 Benchmark DAC-1 vs DAC of < $200 DVD player.

BA DAC will sound same as above components when level matched if it's built as hi-fi equipment. It will be a bad news if it sounds different regardless of price. Once you get 2 of those, play them without level matching effort. Very likely even 2 of the same model will sound different.

Above are level matched DBT posted online. There are tons carried out with same result not posted online. I'd be delighted to read about level matched DBT results agreeing with you. Lets see some.


You are kidding, right? Do you seriously take the first "DBT" test to remotely be accurate?

If so, you know nothing about room interaction or how to set-up speakers.

There is nothing verifiable about this 'test'. I cannot duplicate the conditions. Nor would I want to. Here's a hint: observe the slope of the ceiling to the side of the right speaker. Also observe the lack of room treatment. Even more amusing for me is the reflective surface in front of the speakers. There is simply no possible way that a flat reponse, let alone a stereo image, is possible in that environment.

I hate to get involved in these debates. It's usually pointless. But THAT room is so badly prepared for a DBT, that it must be a joke.
post #79 of 224
Quote:
Originally Posted by CDLehner View Post

Not to ask for a crash course in EE, but can you give me the "gist" of what usually happens with such a combination? Not sure if I can find the input impedance of my power amp, as it's an older model. IYO, what is the sonic consequence of a high output impedance device?

CD

Well, so much for you doing some independent of this forum digging, huh?! LOL!

In virtually all cases, modern audio equipment is designed such that the source has a low output impedance while the destination has a large input impedance. When the ratio of the two is sufficiently high, say about 100:1 (some say at least 10:1) there is negligible voltage drop and unless there's a pathological problem with the source, you can drive (use) cables of long lengths and the total cable capacitance is not much of an issue. Hence, you'll generally find output impedances somewhere in the range of 50 ohms or so with input impedances of 47K or greater. Understand though that while manufacturers specify a single number, in reality the impedance is a dynamic number that varies with frequency. An easy place to see the various numbers of some commercially available equipment would be to peruse the reviews in Stereophile where Atkinson or someone else measures the values.

When the values become proximate, there can be voltage drop issues as well as problems with cables affecting the signal. You may even start to lose your low and high ends.
Quote:
Originally Posted by CDLehner View Post

Actually, I think I was able to find my input impedance...and it looks like it's 100kohm. So, am I "OK"?

CD

Maybe. There are objective ways you can find out provided you have the ability to burn a series of test tones onto a CDR, a regular old CDP, and access to a half decent multimeter.
post #80 of 224
Quote:
Originally Posted by mmiles View Post

Chu,

Michael Ritter and his associate [ I will get the name latter ] helped Pacific Micronics and Sony with HDCP as I recall. I can get more specifics because I know if I mistate, misspell, fart or burp you boys will be all over me.

I suggest you guys go to CES and take say 2-3 days and visit the audio rooms. Most are just bunk but there are some very worthwhile vendors to consider. No I do not own a unit in the sense of having installed in my system but I do have one brand new in a box ready to go for one of you highrollers

The M-Audio appears to be a splitter of sorts that would allow an instrument to go to both the main mixboard and sub board for recording using a digital connection. I am awaiting a reply from them it should be interesting.

As far as Berkeley rebadging a Lynx I cannot say. I do know that Berkeley suggest the LYNX audio card for home brew music servers. Did I say music server? Yes I did. To me this is the prime application of an outboard DAC imho.

Ritter is the principal listed for Berkeley LLC as found by searching the company's name in the California Secretary of State's business database. The address for the company appears to be his personal address.

Quote:


In fact since you brought this up many companies manufacture off shore or use similar if not exact platforms. Audio Control [cut thier teeth in audio analyzers and 12V audio] and Arcam are the same surround processor preamp. Many amp companies use the the same modules especially in the Class D camp. Many speakers use ScanSpeak, SEAS, Focal drivers. Even the once might McIntosh rebadges some Denon and Escient products.

There is definitely a lot of in-breeding going on in this business. No wonder given the complexity of some electronics. If Berkeley rebadges a Lynx product, it's a stripped down version of something. Could be somebody else. But, since you've got one, how's about opening the sucker up, snapping some pics, and let's see what you have there.
Quote:


I wished you guys lived closer I would really love to bring a BAD to your home.
CDL lives close [withen an hour] so maybe he might be the test bed. He is a value oriented guy it appears [just follow his post in various forums here on AVS] and I think would say if it is better that the other DACs he has tried. Now if it is better one may still not want to pay for the price tag. If you look at my post this hobby is a N O T a linear format. I must say the Wilson Maxx III is better than my old Klipsch Cornwalls but not 25-30x better MSRP vs. MSRP.

I've got to deal with Jehovah Witnesses coming by the house now I need some guy bringing over a DAC? No way!

Quote:


Many of you have questioned CDL, RUR and myself [and others] about this or that. So now I ask you, ever listen to or install a Berkeley, EMM Labs, dCs, Esoteric, Apogee, Prism DAC? If not how can you say we [that have] are wrong? I am not saying your wrong and I'm trying my best to be polite and professional when it looks like some of you frankly just want to fight to show off your knowledge or what think is your superior intellect.

You might be right but frankly for your position, whatever it may be, to be taken more seriously by others is probably going to have to meet a higher standard of proof along with statistical treatment of your results. I need a new driveway more than a DAC and from the prices of the DACs I might have money left over.

Quote:


For me I just want to talk audio and learn as much as I can. I found the Berkeley to have a cost effective product to compare and compete against some of those I mentioned. Who knows I will be the first to admit if a $200 box is better. Trust me. In my HT I run Tannoy Pro install products with Audio Control electronics [if I move the demo system I might just go back to pro style amps, Face Audio - google them]. I listened to Tannoy and LapGruppen at a CEDIA 4 yrs ago and they run toe to toe [to me] with Genelec and JBL Synthesis for a third of the cost!

So if there is a better mousetrap I'm all for it. All I ask is do not insight riot and bully yourself around.
post #81 of 224
Quote:
Originally Posted by swspiers View Post
You are kidding, right? Do you seriously take the first "DBT" test to remotely be accurate?

If so, you know nothing about room interaction or how to set-up speakers.

There is nothing verifiable about this 'test'. I cannot duplicate the conditions. Nor would I want to. Here's a hint: observe the slope of the ceiling to the side of the right speaker. Also observe the lack of room treatment. Even more amusing for me is the reflective surface in front of the speakers. There is simply no possible way that a flat reponse, let alone a stereo image, is possible in that environment.

I hate to get involved in these debates. It's usually pointless. But THAT room is so badly prepared for a DBT, that it must be a joke.
I didn't know they were comparing rooms.
post #82 of 224
Quote:
Originally Posted by geekhd View Post

I didn't know they were comparing rooms.

Brilliant.
post #83 of 224
Quote:
Originally Posted by xianthax View Post

yea not that big a deal, drop won't be large enough to matter. The DAC's specs would claim it can drive past both consumer and pro definitions for "line level" anyway, although some devices/amps accept higher input swings.

The main problem with high output impedance, is that device becomes sensitive to cables. Capacity of the cable results in roll off in high frequency range. The longer the cable, the higher is loss of treble. I would suspect that this is done on purpose, for an opportunity to sell exotic cables along with this unit.
post #84 of 224
Quote:
Originally Posted by ap1 View Post

The main problem with high output impedance, is that device becomes sensitive to cables. Capacity of the cable results in roll off in high frequency range. The longer the cable, the higher is loss of treble. I would suspect that this is done on purpose, for an opportunity to sell exotic cables along with this unit.

I think you mean capacitance and i doubt it. Only numbers i've seen for capacitance of speaker cable puts it at about 500pF at 5m and RCAs are generally similar or much lower, at least every cable i've seen that actually lists this spec is. To get a roll off effect in the audio spectrum the output resistance + cable resistance would need to be on the order of ~10,000,000 ohms, which is 3 orders of magnitude above what we are talking about here.
post #85 of 224
Quote:
Originally Posted by ap1 View Post

The main problem with high output impedance, is that device becomes sensitive to cables. Capacity of the cable results in roll off in high frequency range. The longer the cable, the higher is loss of treble. I would suspect that this is done on purpose, for an opportunity to sell exotic cables along with this unit.

Out of curiosity I ran a simulation for this situation:

This is based on a 15ft Belden 1694A RCA cable. I did not model contact effects from the RCA connectors. If someone has reasonable numbers let me know and I'll add the the lumped elements. I couldn't find a conductance number for this cable and didn't calculate one, i can't believe that there would be much if any dielectric loses at these frequencies so i don't expect that to impact the results. The input resistance of the load device (amp) is assumed to be 100k ohm and the input is assumed to be a FET gate so about 15pF gate capacitance is added.

Circuit:



So lets look at the frequency response from 1 to 30khz and sweep the output resistance from 5 ohm to 10k ohm with 10 steps. Blue is magnitude is dB with the scale on the left. Red is phase in degrees with the scale on the right. The closest graph to flat is the lowest output resistance, the graph with the largest attenuation is the highest output resistance.



Lower output impedance is certainly flatter, but even at 10k ohm the response only rolled off 0.4dB at 20khz and phase is off -17 degrees, both inaudible. Not shown to keep the graph clean but at 22k ohm output resistance the response is down 1.3dB and off by -30 deg in phase at 20khz, both still inaudible.

Looking at an amp with a lower load resistance, 32k ohms and sweeping output resistance from 50 -> 22k ohms:



The roll off is actually reduced some, but the overall signal attenuation is much higher, -4.54dB with a 22k ohm output impedance. So again the roll off would be inaudible but the overall signal attenuation may make it impossible to achieve full range input on the next device (the amp in our discussion).
LL
LL
LL
post #86 of 224
Quote:
Originally Posted by Chu Gai View Post

I don't recall anyone in this thread saying they've actually bought this particular DAC from Berkeley and evaluated it in the confines of their home. CDLehner has previously stated that when he evaluates a product for purchase, he listens to it. However, it does not appear, WRT DAC's at least, that he applies critical level matching and some sort of blind testing to aid in his purchasing decision. Indeed, without knowing some of the products he's brought in, the absolute need for this sort of approach may not necessarily be warranted. Regardless, he's been fairly transparent in recounting his approach and in my rereading of this thread has not really tried to impose his methodology upon the world. In fact, he's been rather nice about the whole thing and I don't think he deserves to be pilloried for his view. If his present DAC - an EE tube DAC -puts a little fuzz or whatever on the songs and this makes the experience more enjoyable even if it's not 100% faithful to what's on the disc, so phucking what? More interesting to me at least would be to understand what it is that his DAC is doing. A link to the product page might be useful in getting a feel for what is happening to the signal.

WRT the DAC in this thread, it's of some interest to me as to what's going on with all those filters. The website is largely devoid of details. Yet, some may recall that several years ago the filter/spline game was played by both Wadia, Pioneer and Sony (overseas mostly due to patent issues) and this creates aliasing effects that often are audible. It's rather a pity that Berkeley doesn't say much or that there's no inside view of what's under the cover.

My studio uses 4 of these for 8 channels of DAC. we also share a few pairs of model 2 dacs from pacific microsonics with a couple other studios, as well as owning lynx and apogee dacs. we also have 8 channels of mytek digital AD/DA and to keep everything properly locked in use a big ben clock. we also share some dCS gear with another studio.

The berkley isnt a lynx thats rebadged. at least not as far as I can tell.


Matt
post #87 of 224
I don't think it's a rebadge of an existing Lynx product either, Matt. I also think Berkeley is having them made by someone. Any chance you can open one up and snap some pics of the insides?
post #88 of 224
Quote:
Originally Posted by Chu Gai View Post

I don't think it's a rebadge of an existing Lynx product either, Matt. I also think Berkeley is having them made by someone. Any chance you can open one up and snap some pics of the insides?

Google is amazing. Guess it's because I'm an IT expert.



CD
post #89 of 224
Quote:
Originally Posted by CDLehner View Post

Google is amazing. Guess it's because I'm an IT expert.


CD

Good design, grounding is a bit odd and they made rather excessive use of buffers , be interesting to see the back side of that board.

There is an analog devices SHARC dsp in there, which is actually a very powerful device to be using for 2 channel audio. Any secret sauce in terms of how this thing sounds is in that DSP program. They could be doing anything with the audio.

The actual DAC is the Analog Devices chip to the right hand side of the middle island, with the 2 pairs of traces leading to the analog portions. I can't see the part number on it but AD make several good DACs.

If they are charging $5k for this thing there had better be some serious magic in that DSP program, because the build cost for this thing is probably ~$80-100.
post #90 of 224
Quote:
Originally Posted by xianthax View Post

If they are charging $5k for this thing there had better be some serious magic in that DSP program, because the build cost for this thing is probably ~$80-100.

Well, the faceplate graphic design has to cost a lot. Those designer's fees cost arm & leg.
New Posts  All Forums:Forum Nav:
  Return Home
AVS › AVS Forum › Audio › CD Players & Dedicated Music Transports › Berkeley Audio Alpha DAC