[mrspeakers]

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I think the misunderstanding is that you are talking about headphones and I am talking about speakers. You might want to use headphones with several different amps, but once you've amped your speakers and EQed them to get as flat as you can, there wouldn't be much reason to swap in a different amp.

Actually, the exact same math and considerations apply, though for many amps the ratio of speaker to output impedance is high so this may play less of an effect.  However, lower impedance (4 ohm) speakers are more sensitive to this...
 

 

[maverickronin]

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I don't think that's the problem Mav.  In it's most basic form there's "sounds the same", "sounds similar" and "sounds different" and the party line has been "sounds the same".  I'm not so sure any more.
 
Last week I would have said a lot of stuff will "sound the same"  but now I'm questioning this hypothesis because I'm starting to feel that, if for instance, one dac is using a particular opamp in its analog circuit, and another dac with the same topology and dac chip, is using a different opamp or a mosfet, there is a good chance that these two dacs are not going to sound the same. 
 
I suspose that its possible that some opamps and/or mosfets will sound similar but it's also possible that many don't and if the devices under review have dissimilar sounding opamps or mosfets they will not sound the same.
 
To date, no one has been bold enough to step forward and say all opamps and transistors sound the same, because they would have to offer the same type of proof we require of the cable believers.  I've issued several challenges for diffMaker files and desspite the possibility of false positives there have been no takers so far.
 
It is my belief that opamps, mosfets, PS, topology and shielding all affect the final sound to the extent that if you listen to two devices with different complements of components, they will sound different from each other, in a greater or lesser way.  If I had to guess on the order of the things I've listed, I'd say that opamps and mosfets would make the biggest difference followed by PS.
 
It also hasn't been established if all dac chips sound the same.  And I'm beginning to think that there is more resolution to be gained from the new 32 bit Sabre chips, so that would be another form of not sounding the same.....
 
If you reduce it to audible differences in wire, I'm all in for no differences, but I'm not getting it for complex devices.

To put it another way, all those things are likely to have an effect on the measurements, but not on what you can actually hear.
 
If you take a DAC/amp to pieces and start randomly replacing parts then you're very likely to change the sound but that piece of equipment was designed with those specific parts in mind.  All those parts add up to a whole and the whole is what matters.
 
I'd love to make some difference files though.  If someone sends me a nice ADC I'll be sure to do it.  Once again the problem is that few people are equipped to do this sort of measuring.
 
I also don't get what you mean by "resolution".  Its a very poorly defined term.  Are we talking about distortion, noise floor, dynamic range, something more esoteric like square wave response, or a combination of all of the above?

 

[upstateguy]

Quote:

To put it another way, all those things are likely to have an effect on the measurements, but not on what you can actually hear.
 
If you take a DAC/amp to pieces and start randomly replacing parts then you're very likely to change the sound but that piece of equipment was designed with those specific parts in mind.  All those parts add up to a whole and the whole is what matters.
 
I'd love to make some difference files though.  If someone sends me a nice ADC I'll be sure to do it.  Once again the problem is that few people are equipped to do this sort of measuring.
 
I also don't get what you mean by "resolution".  Its a very poorly defined term.  Are we talking about distortion, noise floor, dynamic range, something more esoteric like square wave response, or a combination of all of the above?

If you take a DAC/amp to pieces and start randomly replacing parts then you're very likely to change the sound....
 
So complicated devices can sound different from each other.  That was my only point.
 
I'd love to make some difference files though.
 
Just download the audio DiffMaker.  It works with what ever you have.  All you need is a cable from your amp to your computer mic input....
 
Record some stuff, swap interconnects and make another recording.  It does the nulling for you.
 
Edit: I also don't get what you mean by "resolution".
 
"resolution"   Listen to a low bit rate mp3 like 128.  That's low resolution.  Now listen to a wav file.  That's higher resolution.  Of the 3 amps I use the GS-1 has a noticeably higher resolution than the M^3, which has a slightly higher resolution than the Woo3.
 
Cleaner,clearer, crisper, bass and treble.

 

[maverickronin]

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So complicated devices can sound different from each other.  That was my only point.
 
Just download the audio DiffMaker.  It works with what ever you have.  All you need is a cable from your amp to your computer mic input....
 
Record some stuff, swap interconnects and make another recording.  It does the nulling for you.

 
Well of course they can sound different.  The question is what sort of standards are most DACs actually built to and are those standards high enough to be transparent to human ear.  There are always exceptions.  You can even make cables bad enough that they audibly degrade the sound if you really try.
 
Also, I tried recording something with my sound card once.  Its ADC is a $DEITY forsaken POS and I can't say I'm benevolent enough to look into what's good and buy one right now.

 

[upstateguy]

Quote:

 
Well of course they can sound different.  The question is what sort of standards are most DACs actually built to and are those standards high enough to be transparent to human ear.  There are always exceptions.  You can even make cables bad enough that they audibly degrade the sound if you really try.
 
Also, I tried recording something with my sound card once.  Its ADC is a $DEITY forsaken POS and I can't say I'm benevolent enough to look into what's good and buy one right now.

Well of course they can sound different.  is not the same as all dacs sound the same.
 
** You can do it with your sound card, everything will be nulled out except the differences.  If there is a difference you will hear it.  Check out the marching band demo on their web site.
 
 
Also see above I added an Edit....

 

[maverickronin]

Quote:

"resolution"   Listen to a low bit rate mp3 like 128.  That's low resolution.  Now listen to a wav file.  That's higher resolution.  Of the 3 amps I use the GS-1 has a noticeably higher resolution than the M^3, which has a slightly higher resolution than the Woo3.
 
Cleaner,clearer, crisper, bass and treble.

Quote:

** You can do it with your sound card, everything will be nulled out except the differences.  If there is a difference you will hear it.  Check out the marching band demo on their web site.

So your amps are applying psycho-acoustic compression.   

  Its an argument by analogy, which is what I mean by poorly defined.  The best I can take "resolution" to mean as it relates to an amp or DAC would be a specific kind of distortion that reduces perceived detail but that still has to be defined somehow before we can go about correcting or measuring for it.  I'd assume it has to do with non-harmonic distortion like IMD or crossover distortion since those are usually the most objectionable.
 
I know I can use diffmaker with hardware I have, I'm just questioning its usefulness with that hardware.  Wouldn't a poor ADC turn any differences that do exist between two DACs into nothing more than noise?

 

[nick_charles]

 
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I know I can use diffmaker with hardware I have, I'm just questioning its usefulness with that hardware.  Wouldn't a poor ADC turn any differences that do exist between two DACs into nothing more than noise?

The Behringer UCA202 is a mere $30 - while not of the very highest quality its ADC section has a resolution (term used correctly here

 ) of about 16 bits, certainly it is good enough to show up any significant (i.e night and day) differences. The incipient error is about +/- 1  LSB or 1 part in 65K (give or take) it is certainly good enough to show up the differences in CD player analog outputs - I used to it show a consistent (over 10 trials each) difference in three CD players of my own and even (the far smaller differences) between cables.
 
Diffmaker is great but the alignment routine is not always spot on - with several different versions it has given me differences between two copies of the same file so I'd check that it does not give false positives first.

 

[Willakan]

I love debates with sane people 

 
@mrspeakers: I'm sticking to DACs for the moment, where load is not so much of an issue. With amplifiers, obviously the load can affect the sound, but in a well designed amp I don't think it should. The AMB M^3 measures uniformly well into a variety of headphone impedances, for example.
 
@Upstateguy
Regarding the power supply issue, the power supply is a potential source of audio signal degradation. It can affect the sound, but should not unless it is crap. Should it audibly affect the sound, this will be apparent in the measurements - even inaudible anomalies caused by the power supply are very easy to measure - I remember Ti Kan on the AMB forums mentioning their presence - but far, far below the levels of audibility.
 
To address your other points:
NOS DACs are nothing like as prominent as ordinary DACs IMO. As I said earlier, NOS DACs are to ordinary DACs as tube amps are to ordinary SS amps. They do something audible to the sound - in the same way that applying equalisation or other forms of digital or analog signal processing (tone controls, digital noise reduction ect) will change the sound. These are clearly measurable things - but as I said in my previous post, no-one is arguing that every DAC will sound the same. If I design a DAC based on some misguided audiophile mythology that measures abominably but makes great square waves - and it obviously sounds different to something that is well engineered - okay, okay, some people may like what NOS DACs do - I'm not doing well at considering my dislike for many of them. But making a DAC that does something of questionable sense to the sound is not what the "DACs generally sound the same" people are actually getting at. They are annoyed by the well measuring cheaper components which inexplicably sound worse than the latest high-end product (according to Stereophile, anyway).
 
We HAVE established the effect of every conceivable component in the DAC because, in the end, the effect of every single component will be represented by the overall measurements. You can marvel that modern electronics and the designers that work with it can take huge numbers of components and make them behave in extraordinarily predictable ways, but in the end if you have a DAC that measures far, far beyond the threshold of audibility, why should it concern you what "effect" the power supply has? Every component has an effect, but these effects are run in simulations, balanced and accounted for - to switch to the world of amps for a moment, the Beta22 was designed almost entirely using computer simulation. Additionally, these are tiny changes - circuit boards are optimised to reduce crosstalk and the like quickly, and largely by computer - but the resulting differences would probably be inaudible anyway. These designs are done to an extremely high standard - on one level it is miraculous that faced with the huge array of components even good designers can consistently churn out stuff that measures ludicrously well, but with the aid of science and modern technology, it is none-the-less the honest truth. 
 In the end, if the overall measurements say everything is inaudible, demanding how each individual component affects the measurements is academically interesting, but does not have any bearing on what the overall measurements show - an effectively perfect product.
 
Your comments about the resolution of the chip: The latest Sabre chip almost certainly has more resolution, but not more audibly. The reason DAC chips keep on improving is firstly for practical reasons - pushing ahead with techniques to get better and better measurements will trickle down to cheaper designs - for example, the manufacturer of a TV with a digital TV receiver would doubtless be interested in a DAC chip to process the sound part of the digital TV signal that requires less and dirtier power to do its job as well as the one they were previously using. Secondly, there is a demand for better chips - gotta have something to sell the audiophiles - and the engineers that design them would rather give genuine, if completely and utterly inaudible beyond all shadow of a doubt, improvements.
 
The reason I admittedly tried to avoid that question is because I respect Tangent - his website is full of invaluable information for the audio DIYer. However, the time comes when you have to bite the bullet for your beliefs, so I'll say that if an opamp is properly served by the design (eg taking into account its power requirements and varying input impedance) and it measures above a certain level - see previous posts so we don't get back to the defining an exact level problem, it sounds exactly the same as other well-measuring opamps. Besides, the general consensus on opamp sounds varies from forum to forum IMO to some extent, although this may be inherent bias on my part.
 
Regarding your question about mosfets, I feel it's time to use an analogy, which is probably going to be awful, for which I apologise, which will hopefully explain my outlook on this idea of how there are so many factors involved, differences that are audible must result. Imagine you have several monstrously complex equations, all of which perform roughly the same mathematical task - say to work out the strength of foundations required to support a building. Both equations are fed with huge numbers of values to their variables; some variables are the same across both, some specific to one equation. In the end, they both turn out exactly the same number, give or take a few thousands of a gram of load-bearing ability. (Wow, this really is a bad analogy, but I'll soldier on regardless). Both approaches, due to the advanced scientific knowledge behind each of them, have effectively both arrived at a solution that is to all intents and purposes, perfect. This can be compared to two well designed DACs producing effectively audible output. Simply pointing to the different values some of them are fed with, or their different approaches, does not disprove the fact that they both did their job supremely well. We can marvel at how different their approaches are and how they have dealt with incredible complexities, but the facts remain the same.
 
Regarding your Benchmark vs DACmagic request for proof - going to use another analogy, sorry. I have two objects which I have measured to all intents and purposes to be identical ( the human eye being unable to detect 0.0005% differences in diameter on a 10cm wide cylinder, for example). If someone suggests they are perceptibly different, the burden of proof is upon them, not me, to demonstrate that they are correct.
 
 
 
 
 
 

 

[upstateguy]

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So your amps are applying psycho-acoustic compression.   

  Its an argument by analogy, which is what I mean by poorly defined.  The best I can take "resolution" to mean as it relates to an amp or DAC would be a specific kind of distortion that reduces perceived detail but that still has to be defined somehow before we can go about correcting or measuring for it.  I'd assume it has to do with non-harmonic distortion like IMD or crossover distortion since those are usually the most objectionable.
 
I know I can use diffmaker with hardware I have, I'm just questioning its usefulness with that hardware.  Wouldn't a poor ADC turn any differences that do exist between two DACs into nothing more than noise?

 
I always defer to Nicky when it comes to definitions but the "resolution" I was describing was something different.  There are two components to the "resolution" difference I hear between the GS-1 and my other two amps.
 
First, if you can imagine the music from an amp playing in a room, the GS-1 plays in a larger room than the other two.  It's similar to, but not exactly the same as the spacial thing you hear when you go from a standard headphone like the 650 to one of the new angled driver headphones like the T-1.
 
The second thing that's noticeable is the clarity of the textures of instruments and voices, both in the bass, where notes are very clearly defined and in the treble where things are just crisper and clearer, or conversely the other two amps area little fuzzier in the details at the beginning and end of notes.
 
For this reason the GS-1 has become my preferred amp over the M^3 and the Woo3.
 
I don't have a clue if this is measurable, but it is audible.  I've had the amps for years and have had a chance to spend long hours with each of them. During this time the GS-1 has emerged as the preferred amp of the three.
 
 


Quote:

The Behringer UCA202 is a mere $30 - while not of the very highest quality its ADC section has a resolution (term used correctly here

 ) of about 16 bits, certainly it is good enough to show up any significant (i.e night and day) differences. The incipient error is about +/- 1  LSB or 1 part in 65K (give or take) it is certainly good enough to show up the differences in CD player analog outputs - I used to it show a consistent (over 10 trials each) difference in three CD players of my own and even (the far smaller differences) between cables.
 
Diffmaker is great but the alignment routine is not always spot on - with several different versions it has given me differences between two copies of the same file so I'd check that it does not give false positives first.

 
Apologies for the the incorrect use of resolution. 

 
I supose that you could also do the null test by hand with Audacity.  Ti Kan did one for me that way a few years ago.  It showed a difference of -45dB between two opamps.
 
USG
 
 

 

[bigshot]

First, if you can imagine the music from an amp playing in a room, the GS-1 plays in a larger room than the other two.  The second thing that's noticeable is the clarity of the textures of instruments and voices, both in the bass, where notes are very clearly defined and in the treble where things are just crisper and clearer, or conversely the other two amps area little fuzzier in the details at the beginning and end of notes.

I'm no expert on headphone amps, and the way you're describing it leaves a lot of room for interpretation, but that sounds to me like the difference between an underpowered amp and one that has sufficient power. The way I describe that is "dynamic punch". If you don't have enough power to put across the peaks (percussive attacks), it tends to flatten out the sound.

If that's what you're talking about, resolution isn't the best way to describe it, but I can see how you would interpret it that way. If the problem was frequency response, it probably wouldn't affect the whole spectrum from low to high evenly. If it was distortion, it wouldn't affect the size of the sound. It must be something to do with dynamics. I had the same sort of effect when I upgraded the amp in my speaker setup to a more powerful amp that was able to handle the big transients better.

 

[Willakan]

DBT your amps

. The obvious cheap shot easy-ass answer from my perspective aside, it would be very interesting to see the results. I'm always open to belief-shattering revelations, and you seem like someone who can easily address all major concerns (volume matching ect).
Also a 45db null is pretty hard to hear, but certainly within the realms of audibility - can you remember the two opamps on test? I would imagine that one of them would be an old/cheap opamp, but can't really make any personal assumptions until I know the opamps involved.
EDIT: @Bigshot - Not sure, the M^3 can quite happily drive speakers with a few minor tweaks - I don't think it could be accused of lacking in power.

 

[bigshot]

Willakan brings up the problem of volume matching. If you detected these differences in direct A/B comparison, a slight difference in line level would result in the same sort of effect. It's unlikely that would make a difference if your comparison was made with a space of time between samples. If that's the case, you are probably detecting slight differences that don't really exist. Subtle differences always require direct A/B comparison.

 

[upstateguy]

Quote:

I'm no expert on headphone amps, and the way you're describing it leaves a lot of room for interpretation, but that sounds to me like the difference between an underpowered amp and one that has sufficient power. The way I describe that is "dynamic punch". If you don't have enough power to put across the peaks (percussive attacks), it tends to flatten out the sound.

If that's what you're talking about, resolution isn't the best way to describe it, but I can see how you would interpret it that way. If the problem was frequency response, it probably wouldn't affect the whole spectrum from low to high evenly. If it was distortion, it wouldn't affect the size of the sound. It must be something to do with dynamics. I had the same sort of effect when I upgraded the amp in my speaker setup to a more powerful amp that was able to handle the big transients better.

I doubt power is an issue.
 


Quote:

DBT your amps

. The obvious cheap shot easy-ass answer from my perspective aside, it would be very interesting to see the results. I'm always open to belief-shattering revelations, and you seem like someone who can easily address all major concerns (volume matching ect).
Also a 45db null is pretty hard to hear, but certainly within the realms of audibility - can you remember the two opamps on test? I would imagine that one of them would be an old/cheap opamp, but can't really make any personal assumptions until I know the opamps involved.
EDIT: @Bigshot - Not sure, the M^3 can quite happily drive speakers with a few minor tweaks - I don't think it could be accused of lacking in power.

 
The two opamps were the 637/627 arrangement and 3, 8610s in my M^3.  It all started with Ti saying that opamps didn't make a big difference in an M^3.  I said I could hear a difference between a 637/627 and an 8610.  Ti said they sounded exactly the same in an M^3.  I recorded the files showing the differences I heard and sent them to him.   He did a null test by hand/eye in audacity and sent me back the result.  I could hear it with the volume all the way up.

 
Quote:

Willakan brings up the problem of volume matching. If you detected these differences in direct A/B comparison, a slight difference in line level would result in the same sort of effect. It's unlikely that would make a difference if your comparison was made with a space of time between samples. If that's the case, you are probably detecting slight differences that don't really exist. Subtle differences always require direct A/B comparison.

 
I've had years to compare these amps and on a few different rigs.  Sometimes it's very hard to tell the difference between the 637/627 M^3 and the Woo3 with a Cetron tube, but the GS-1 always sounds different, and to me better, in that spacial way I described.
 
Edit:  even at a slightly lower volume, the GS-1 plays in a larger room than the other two.
 
 

 

[bigshot]

If everything else sounds basically the same and just the one amp sounds different, that amp must be doing some sort of processing to deliberately make it sound different. Maybe it's monkeying with the phase. I don't think a headphone amp would incorporate a digital delay, but that would sound very much like what you describe too. In any case, the amp you like is probably the one that isn't performing to spec. If you like it that way, it doesn't matter though.

Have you done direct line level matched A/B comparison? That would probably help you define exactly what the difference is. It would be easier to figure out if your description wasn't so vague. I suspect that the phase/time shifting you're describing doesn't really exist, and some other more common problem is just giving you that impression.

 

[Willakan]

Just to say, when a difference is nulled out and recorded in Audacity, the fact you have to turn it up to max volume to hear it - and that is when the difference is isolated into a result track - implies that the difference is probably inaudible under normal usage; but I do find the -45db difference very interesting - it is unfortunate that a more detailed investigation, (investigating the effect of the voltage fed to the opamps for example) will likely never be performed. These are both very high-end opamps - I will PM Ti on his forums to see if I can get more info, he's usually extraordinarily helpful as you well know.
And the Woo3 is a tube amp - we KNOW tube amps have giant measurable differences versus SS, so I find it especially interesting that you declare they sound incredibly similar (Woo and M^3). Assuming the M^3 does not actually measure strangely for a SS amp, which I find very unlikely...hmm, will ask Mr Kan.
 
However, the Woo3 is a relatively high-end tube amps, and tube amps can still have inaudible levels of distortion and so on when well designed - my immediate reaction is to wonder what the GS-1 is doing to the sound - but speculation isn't particularly fruitful - it could be much higher than advertised crosstalk - crosstalk is rarely perceived in small amounts (well, small in the sense of audible, but not blatantly obviously audible within a second of listening) as a degradation and can have all the effects on the sound stage you spoke of. Faced with a larger subjective soundstage, it can be easier to isolate details - but this is a lot of speculation here. AFAIK the GS-1 has never ended up being measured.