[maverickronin]

Quote:

Scientific inquiry is more a journey than a final destination.

I agree.  Science is a verb.
 
I still don't think that makes it a good idea to make decisions on where you thing think or hope the road might lead.  That's all I advocate here.

 

[leeperry]

Originally Posted by maverickronin /img/forum/go_quote.gif
 
There are plenty of situations where blindly switching opamps could change the sound but from a technical point of view as long as the circuit isn't already atrocious then the only change you're likely to hear would be a degradation of the sound caused by new opamp becoming unstable, ringing, oscillating, or something in that particular circuit because it wan't designed for it.  If it ends up working fine in same circuit and is a decent op amp then any differences should be inaudible.

Yeah well, I've tried to roll opamps in the Firestone Fubar III and I couldn't detect any SQ difference whatsoever. Reasons? A crappy pot mainly that completely fubars the SQ. A cheapo ubber-jitterry DAC chip too I would guess(same family as the horrid sounding PCM2704). You're only as strong as your weakest link. It'd be like using top of the range tyres on a POS car.

 

[maverickronin]

Quote:

Yeah well, I've tried to roll opamps in the Firestone Fubar III and I couldn't detect any SQ difference whatsoever. Reasons? A crappy pot mainly that completely fubars the SQ. A cheapo ubber-jitterry DAC chip too I would guess(same family as the horrid sounding PCM2704). You're only as strong as your weakest link. It'd be like using top of the range tyres on a POS car.

Its not exactly established that most of those differences are actually audible either...

 

[Prog Rock Man]

Quote:

The crosstalk measurement (yes, I know what crosstalk is) matches what I heard and I know the design wasn't intended to perform in a completely linear manner. So unless there is another measurement which gives a similar V-shaped frequency response matching what I heard, then, as far as I'm concerned, the effect of it is audible.
 


 
We aren't talking about how good or bad these things are. The question was: Why do OPAMPs sound different? That question is, essentially: Why do amplification circuits sound different? I provided an answer, with measurements as an example. Aside from that, the owner of Audio-gd, as well as other people I have consulted when I want to understand what is going on in audio gear, are highly experienced engineers. Unless you have similar qualifications, I think I'd take their explanations over yours. 
 
It's clear a number of people in this forum have the attitude one the one hand that something has to be proven to be true and everything else is placebo. When it is proven, but goes against whatever argument they have, it's "inaudible" or something else. I see little to no interest from people here in learning anything, especially not genuine science (discovering the truth), not even learning how audio equipment works, just an interest in bashing beliefs over other people's heads.  
 

You can prove something is audibly different (as in a difference that is detectable by using our ears and no other sense) by ABX testing which results in clear passes, measuring and finding a decibel difference which is known by previous studies to be in our audible range and null testing where what is left is audible. If ABX tests, measurements and null tests find no difference, then all we are left with is placebo/hype/buyer justification etc.
 
I see those who claim audible differences where there are none inherant in the component under discussion as the ones who have little interest in learning and science. That is primarily down to their refusal to even discuss the possibilities the differences are caused by them and not the component.
 
The biggest problem is the number of people, who when faced with evidence contrary to their own belief/opinion (which tends to be those who say cables, opamps etc make differences) revert to abuse such as claims of having their heads bashed in.
 
 

 

[leeperry]

 
Its not exactly established that most of those differences are actually audible either...

Well, this is a well known fact that crappy pots butcher the SQ(and the pot of the Fubar 3 is crappy to the utmost): http://www.google.com/search?q=stepped+attenuator+vs+potentiometer+distortion
 
Have you ever tried a high quality stepped pot? or better, no pot in the signal path whatsoever? I think your lack of real world experience biases your opinion. All the opamps sound the same, all the pots sound the same....as been previously said, the science forum of head-fi feels like an endlessly broken record where anything that isn't entry level is either placebo or snake oil.
 
If some DAC's cost $1K or more, there's one good reason to that: that's because they sound damn good, and are a far cry from a $199 DAC...better component all around do pay in cash in the end SQ-wise: better pot, better PSU, better opamps, better caps, better clocks/reclocking...everything isn't marketing bs my friend. And calling bs w/o hearing it for yourself doesn't make any sense whatsoever. There's always something better sounding out there, but the last few % will cost ya.

 

[Prog Rock Man]

I agree that the volume control is the often ignored cause of SQ problems. I think it is worthy of a thread in itself, not just hijacking this one on opamps.
 
If it found that a £200 DAC performs as well as a £1000 one in a sound test performed by others, that will have a major impact on my decision as to which one I would buy. Most of us cannot audition loads of DACs, particularly side by side, so it is not b/s to take others experince into account when making your own decision.
 
So far with regards to this thread and the evidence presented so far, I think it more likely than not opamps have no inherant impact on sound quality.

 

[nick_charles]

Quote:

Well, this is a well known fact that crappy pots butcher the SQ(and the pot of the Fubar 3 is crappy to the utmost): http://www.google.com/search?q=stepped+attenuator+vs+potentiometer+distortion
 
Have you ever tried a high quality stepped pot? or better, no pot in the signal path whatsoever? I think your lack of real world experience biases your opinion. All the opamps sound the same, all the pots sound the same....as been previously said, the science forum of head-fi feels like an endlessly broken record where anything that isn't entry level is either placebo or snake oil.
 
If some DAC's cost $1K or more, there's one good reason to that: that's because they sound damn soon, and are a far cry from a $199 DAC...better component all around do pay in cash in the end SQ-wise: better pot, better PSU, better opamps, better caps, better clocks/reclocking...everything isn't marketing bs my friend. And calling bs w/o hearing it for yourself doesn't make any sense whatsoever. There's always something better sounding out there, but the last few % will cost ya.

Things that are measurably different are not always audibly different, agreed ?
 
What is the magnitude of differences (between) and absolute levels of distortion for different Pots ?
 
If a pot adds 0.005% distortion that just is not going to be audible, 0.5% or 1% maybe, 2% or 3 % very likely - still I would like to see controlled tests to back these assertions up , can you cite any ?
 
Elsewhere someone contended that they heard differences in crosstalk, but going from -72db to -82db is simply going from inaudible to inaudible (way out of human detection), heck vinyl is considered acceptable at -30db and is often worse than -15db at lower frequencies - the IBA (1960s) guidelines based on human experiments suggest -30db is undetectable and no (competent) SS component is ever worse than about -50db (AFAIK)
 
 

 

[Willakan]

Currawong, the v-shape is also evident in the distortion measurements, hence my correlation of them. If you want to demonstrate that crosstalk is the relevant measurement, you have a substantial burden of proof to demonstrate that such levels of crosstalk are audible. I resent the other implications you appear to make, as they are unsubstantiated and possibly hypocritical (in the case of seeing a graph which seemed to vaguely correspond to what you heard and taking that as a perfect "proof" of their relation prettymuch epitomising the "not want to learn anything" attitude you seem to be attributing to me.) Apologies if that refers to someone else, but that was the impression I got from the post.
 
@leeperry - referring to your reply to my most recent post, no-one is saying every single DAC sounds the same. Straw men are not meant to be blatantly obvious.
 
EDIT: Nick_charles speaks truth, as always 

 

[Prog Rock Man]

Continuing with audibility, are any of these differences within our audible range?
 
http://audio.an-pan-man.com/files/rmaa/earth_vs_moon_vs_sunv2_vs_lt1469.htm
 
It comes to something that I want verification of the evidence presented by one side as they seem to think a measured difference means there IS an audible one.

 

[Willakan]

I would recommend reference to the SG-Acoustics tests, they were not done with RMAA and are much more comprehensive. Both the Sun and Moon discrete opamps are measured.

 

[maverickronin]

Quote:

Well, this is a well known fact that crappy pots butcher the SQ(and the pot of the Fubar 3 is crappy to the utmost): http://www.google.com/search?q=stepped+attenuator+vs+potentiometer+distortion
 
Have you ever tried a high quality stepped pot? or better, no pot in the signal path whatsoever? I think your lack of real world experience biases your opinion. All the opamps sound the same, all the pots sound the same....as been previously said, the science forum of head-fi feels like an endlessly broken record where anything that isn't entry level is either placebo or snake oil.
 
If some DAC's cost $1K or more, there's one good reason to that: that's because they sound damn soon, and are a far cry from a $199 DAC...better component all around do pay in cash in the end SQ-wise: better pot, better PSU, better opamps, better caps, better clocks/reclocking...everything isn't marketing bs my friend. And calling bs w/o hearing it for yourself doesn't make any sense whatsoever. There's always something better sounding out there, but the last few % will cost ya.

You know just because I don't own any expensive DACs or amps doesn't mean I've never heard them.  Of course, even if I hadn't, the measurements and listening tests that other people have conducted still back me up.

 

[leeperry]

Things that are measurably different are not always audibly different, agreed ?
 
What is the magnitude of differences (between) and absolute levels of distortion for different Pots ?
 
If a pot adds 0.005% distortion that just is not going to be audible, 0.5% or 1% maybe, 2% or 3 % very likely - still I would like to see controlled tests to back these assertions up , can you cite any ?

 
Well, crappy pots have many possible issues(and it'll take a lot of money to get a near-perfect pot):
-stereo imbalance at low volume
-random levels of THD depending on the output volume
-loud static when they get old
 
Some links about stepped attenuators and why they're good:
http://diyaudio.co.kr/wwwboard1/data/board1/compare.pdf
http://www.dact.com/html/attenuator_data_sheet.html
 
To get back OT, why do opamps sound different?
 
Mostly coz they use completely different layouts. I already posted a diagram of what happens in an AD797, basically the opamp is one of the most breakthrough inventions of the past half-century in the electronic field. They're essentially a low cost integrating circuit consisting of transistors, resistors and capacitors. Of course, to team "everything sounds the same" this won't mean much. But you can't seriously expect any circuit to sound the same in any given situation. Again, an opamp is an analog device...there's no digital processing whatsoever.
 
Now, measuring THD/SNR/IMD won't learn us much...why so? Let's take another analogy: get a cheap LCD screen and a top of the range plasma, calibrate them using a colorimeter to D65/2.4/SMPTE-C. Yes, once properly calibrated they will measure the exact same colorimetry-wise! Now, would you say that they look the same? I hope not.
 
It's the same story w/ opamps, there's a theory(and MadMax might want to refresh my memory) that the SQ difference between opamps can be measured via "impulse responses". Running FFT measurements, you should be able to measure the differences. RMAA is not up to the task, the same way it won't measure any difference between drastically different sounding cables or DAC's(oh boy). But as usual, noone's bothered measuring those differences....because just like jitter, you need expensive gear to capture the differences and time is money. Some ppl seem too lazy to try it for themselves, so they throw meaningless RMAA measurements and try to convince other inexperienced ppl that everything in the audio world is placebo.
 
There is no question that most of the records made in the 80's/90's sound really crappy thanks to the ubiquitous NE5532. I'd even dare saying that when you have a pretty transparent rig, you can easily identify the color of the opamps that were used during production.
 
I passed this test: http://www.head-fi.org/forum/thread/502889/
 
And yes, I can hear the 5532 color that the STX uses on its line-in. Instead of saying that "everything sounds the same, duh"...why don't you try passing this test? it's easy as 123.

 

[Willakan]

Only one set of measurements on this thread are done with RMAA and the screen analogy is facile. You are seriously suggesting the differences between screens are not measurable?
The "impulse response" thing is a factor of several...you guessed it...measurements. Secondly, you do not need expensive gear to capture the differences between cables, as Nick_charles has shown. Doesn't make them any less inaudible though.
Secondly, why are you using jitter as an example? We can measure jitter. There is absolutely no evidence at all to suggest that the amounts of jitter found in modern audio equipment is even remotely audible. For it to be audible, conditions would have to arise that caused the sensitivity of a listener to timing variation to increase by at least an order of magnitude. Obviously, if there was evidence to suggest this could actually happen it would have turned science on its head by now.
 
Looking at the test you mentioned, he hasn't matched the volumes. This will result in genuine audible differences, that are ironically unlikely to be perceived as differences in amplitude. There are also tonnes of other opportunities for differences to result (the process he used is hardly procedurally perfect). Attributing them to opamps is an unjustified leap of judgment.

 

[Prog Rock Man]

Quote:

 
Well, crappy pots have many possible issues(and it'll take a lot of money to get a near-perfect pot):
-stereo imbalance at low volume
-random levels of THD depending on the output volume
-loud static when they get old
 
Some links about stepped attenuators and why they're good:
http://diyaudio.co.kr/wwwboard1/data/board1/compare.pdf
http://www.dact.com/html/attenuator_data_sheet.html
 
To get back OT, why do opamps sound different?
 
Mostly coz they use completely different layouts. I already posted a diagram of what happens in an AD797, basically the opamp is one of the most breakthrough inventions of the past half-century in the electronic field. They're essentially a low cost integrating circuit consisting of transistors, resistors and capacitors. Of course, to team "everything sounds the same" this won't mean much. But you can't seriously expect any circuit to sound the same in any given situation. Again, an opamp is an analog device...there's no digital processing whatsoever.
 
Now, measuring THD/SNR/IMD won't learn us much...why so? Let's take another analogy: get a cheap LCD screen and a top of the range plasma, calibrate them using a colorimeter to D65/2.4/SMPTE-C. Yes, once properly calibrated they will measure the exact same colorimetry-wise! Now, would you say that they look the same? I hope not.
 
It's the same story w/ opamps, there's a theory(and MadMax might want to refresh my memory) that the SQ difference between opamps can be measured via "impulse responses". Running FFT measurements, you should be able to measure the differences. RMAA is not up to the task, the same way it won't measure any difference between drastically different sounding cables or DAC's(oh boy). But as usual, noone's bothered measuring those differences....because just like jitter, you need expensive gear to capture the differences and time is money. Some ppl seem too lazy to try it for themselves, so they throw meaningless RMAA measurements and try to convince other inexperienced ppl that everything in the audio world is placebo.
 
There is no question that most of the records made in the 80's/90's sound really crappy thanks to the ubiquitous NE5532. I'd even dare saying that when you have a pretty transparent rig, you can easily identify the color of the opamps that were used during production.
 
I passed this test: http://www.head-fi.org/forum/thread/502889/
 
And yes, I can hear the 5532 color that the STX uses on its line-in. Instead of saying that "everything sounds the same, duh"...why don't you try passing this test? it's easy as 123.

Non sequitur and one that is commonly used in all sorts of arguments on hifi forums. It looks different, it measures different, I hear a difference so that difference is caused by it. Wrong.
 
Not everything is placebo and not everything sounds the same, please stop pushing those exaggerated fallicies.

 

[leeperry]

Originally Posted by Willakan /img/forum/go_quote.gif
 
You are seriously suggesting the differences between screens are not measurable?

Colorimetry-wise, they will measure the exact same. That was my point, and I rest my case that trying to measure the SQ difference between opamps or cables using RMAA doesn't make any sense whatsoever. Try something a bit more advanced.

Originally Posted by Willakan /img/forum/go_quote.gif
 
you do not need expensive gear to capture the differences between cables, as Nick_charles has shown. Doesn't make them any less inaudible though.

 
From what I've seen, his attempts at measuring the SQ difference between cables have been a major failure. Try a more advanced measurements package next time. Eating soup w/ a fork doesn't work, it never will.

Originally Posted by Willakan /img/forum/go_quote.gif

Secondly, why are you using jitter as an example? We can measure jitter. There is absolutely no evidence at all to suggest that the amounts of jitter found in modern audio equipment is even remotely audible. For it to be audible, conditions would have to arise that caused the sensitivity of a listener to timing variation to increase by at least an order of magnitude. Obviously, if there was evidence to suggest this could actually happen it would have turned science on its head by now.

 
So all the data available about WM8804 is bs too? http://hifiduino.blogspot.com/2010/02/programming-wm8804.html
 
Wolfson have worked on its 50ps reclocking to only look good on paper in your humble opinion? They have more white papers on the right side of this page(even from the AES, God forbid!): http://www.wolfsonmicro.com/products/spdif_transceivers/WM8804/ 
 
Have you heard what a good reclocker can do before saying that jitter is inaudible? I bet you haven't. There are several WM8804 solutions on the market, and everyone I know who's tried them to reclock toslink to coax has been stunned.

Looking at the test you mentioned, he hasn't matched the volumes. This will result in genuine audible differences, that are ironically unlikely to be perceived as differences in amplitude. There are also tonnes of other opportunities for differences to result (the process he used is hardly procedurally perfect). Attributing them to opamps is an unjustified leap of judgment.

 
Have you listened to the two samples? Do they sound the same to you? This is an honest question, begging for a simple answer.
 

Non sequitur and one that is commonly used in all sorts of arguments on hifi forums. It looks different, it measures different, I hear a difference so that difference is caused by it. Wrong.
 
Not everything is placebo and not everything sounds the same, please stop pushing those exaggerated fallicies.

 
Well, it very much sequitur, I can tell you that. At least from where I stand.
 
In 4 pages times, I've been told that the quality of a pot doesn't matter, that the differences between opamps are so minute that they are inaudible(based on what real world experiments and in what conditions? God only knows), and that most DAC's sound the same too due to those minute differences between their output stages.
 
I like the diyaudio.com forum because it's full of ppl who try stuff, you know, the so-called "real world experience" and then they give honest feedback about what they've heard. A while ago, I found a comparison of PCM1793/CS4398 that matched exactly what me and other head-fi members have heard. Would you call it some sort of "collective hallucination"?
 
Once more, lookee lookee what I've found: http://www.diyaudio.com/forums/solid-state/169484-what-wrong-op-amps.html

OpAmps do have their own sound, the fact that we seem able to pick up on these tiny differences always amazes me, but we do.

 

Each OP-Amp type has it's own THD/IM spectrum, strongly independend from the layout and load conditions so as the quality of power supply

 
It's 24 pages long too, and I'm sure Scott Wurcer(the designer of many top of the range audio opamps, including AD797) must have given his opinion in there as well. Would you say that these ppl are delusional? Don't you find it a bit of a problem to talk about equipment you haven't heard? Roll some opamps, hear for yourself. If LT1028, AD797, OPA827, ADA4627 sound the same to you....well, at least you tried.