Bob Cordell on his lecture on BAF vocalized the definition of coloration that I always shared: it is how the amp misbehaves.
...the page number 208, post number 4161... Hmmm... ;-)
...the page number 208, post number 4161... Hmmm... ;-)
Some equipment is designed for, or preferred for, certain coloration. I have a Phoenix Audio DRS-1 preamp that sounds gorgeous on acoustic guitar and vocals, but not much else (because of it's particular distortion). Use that with a Schoeps CMC-641 mic on acoustic guitar and it sounds so very excellent. Then into the Distressor with a little additional distortion switched in. People love it, and want to know how to get that sound.
Obviously, I don't want my playback system to to that, however.
Obviously, I don't want my playback system to to that, however.
Obviously, tools for colouration and for reproduction are totally different. 😀
I realised how to make distortions inaudible while designed synthesizers and guitar/voice effects.
When was the last time you had a hearing test from an audiologist? Serious question.
I had one last year after suffering a ruptured eardrum from flying with a sinus infection. It was a tiny "pin-hole" perforation and interestingly enough there was a 6dB loss at 150Hz from it, but not much else. Once healed it went away.
It would be nice to establish that people claiming to hear subtle differences between good op-amps have functional hearing. Would you believe a Stereophile reviewer that needed a hearing aid?
Scott, you need a hobby.
Knock it off.
When Ed, or if Ed gets his box out, I and others may make fools out of ourselves or not. Then we can see.
Until then or unless someone else does up a "test platform", all this negativity adds nothing.
Why not HELP the process? You will be proven right sooner then, won't you?
Scott, the listening test for the JC-3 phono amp was done about 10 years ago. A previous test comparing the 5534 to one of my discrete class A op amps was done about 38 years ago, when it first came out. The only other listening test involving op amps is when I removed that AD712 from the Parasound amp where I was initially responsible for putting it in, because of my positive professional relationship with you at the time, and that was just a removal and adding a shorting wire. We all heard that difference too, back in 1992 or about 24 years or so. Not just me, but my design associate Carl Thompson, and of course, the reviewers at 'Stereophile'.
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Maybe a simpler to implement variation on this test would be as follows-
Make a handful of boxes with two options, stereo pairs. Some have identical opamps in both. Others have different opamps or even wire bypasses. Mix up the options. Ensure no one knows which is which and mark them with random numbers. E.G. mount the boards with parts down in the boxes so you can't see which is which. Randomize the lids with the numbers and have someone else screw them on.
Then just circulate individual boxes with the question: same or different? Collect the responses by box number and then correlate them. If it is easy to tell opamps apart you should be able to identify which are same and which are different from the responses without even opening the boxes to determine which is which. If the core question is whether opamps "sound different" this could effectively put it to rest.
Keeping it simple would make it possible to make more boxes and distribute to more willing test subjects. Use cal labels over the screws to keep people out until the test cycle is over.
Adding more questions, like "which sounds better" actually would make a test much more difficult and less likely to produce solid, meaningful results.
And, of course, if the opamps are not implemented intelligently all this may prove is that you need to know what you are doing. . .
Make a handful of boxes with two options, stereo pairs. Some have identical opamps in both. Others have different opamps or even wire bypasses. Mix up the options. Ensure no one knows which is which and mark them with random numbers. E.G. mount the boards with parts down in the boxes so you can't see which is which. Randomize the lids with the numbers and have someone else screw them on.
Then just circulate individual boxes with the question: same or different? Collect the responses by box number and then correlate them. If it is easy to tell opamps apart you should be able to identify which are same and which are different from the responses without even opening the boxes to determine which is which. If the core question is whether opamps "sound different" this could effectively put it to rest.
Keeping it simple would make it possible to make more boxes and distribute to more willing test subjects. Use cal labels over the screws to keep people out until the test cycle is over.
Adding more questions, like "which sounds better" actually would make a test much more difficult and less likely to produce solid, meaningful results.
And, of course, if the opamps are not implemented intelligently all this may prove is that you need to know what you are doing. . .
Regarding sending out hardware boxes equipped with mechanical attempts to prevent cheating, if there is going to be cheating, what's to prevent electrical tests?
If sending out boxes, to a large extent you have to trust people and hope their desire to arrive at some kind of shared truth will outweigh any potential motivation for cheating. That being said, it wouldn't hurt to take some simple steps to discourage opening the boxes out of curiosity.
On the issue of asking which sounds better, it depends if you want to know if people have an aesthetic preference for one kind of distortion over another, assuming any audible distortion occurs.
If sending out boxes, to a large extent you have to trust people and hope their desire to arrive at some kind of shared truth will outweigh any potential motivation for cheating. That being said, it wouldn't hurt to take some simple steps to discourage opening the boxes out of curiosity.
On the issue of asking which sounds better, it depends if you want to know if people have an aesthetic preference for one kind of distortion over another, assuming any audible distortion occurs.
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All these concocted ABX tests you guys come up with! The the most laughable was the one with the snare drum with induced distortion. Mooly's piled up mass of chips. This and that DAC: All miss the point!
You need relatively pure ALL analog sources to start with. For most of us that means vinyl.
You need relatively pure ALL analog sources to start with. For most of us that means vinyl.
Why was Mooly's test laughable? All the opamps sounded different in the particular circuit. What else was it supposed to show?
Also, why do we need analog sources? We will be listening through amplifiers and speakers that have distortion and are imperfect. You can still hear a lot of other upstream distortion sources anyway. Same with DACs in my experience, you can still hear distortion from stuff used in making the digital source (assuming the DAC is a good one). So, where is the problem?
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You are hearing compounded distortion's this way. Not a good test for one gain stage.
Show us examples of analog recordings of the differences in DAC's. Fremer passes around digital recordings of different phono cartridges to show the differences. I have not seen the alternative, ever. What analog system has the dynamic range, freedom from distortion and even the flat response necessary to not swamp the errors in even a modest ADC/DAC today. You can get a codec with 100 dB SNR and -100 dB distortion products for around $3.00 in volume. That's not possible with analog tape or vinyl at any price.
And its a distraction. If the opamps sound different they should sound different with analog or digital sources. And there is nothing in the protocol to preclude someone from trying either.
And its a distraction. If the opamps sound different they should sound different with analog or digital sources. And there is nothing in the protocol to preclude someone from trying either.
Oh, I dunno. Some wide 30ips tape would possibly be able to record the output of DAC units (not chips) and reproduce their differences. Unless of course, you think that they do not sound different, in which case it would show that instead. 😀
Not terribly practical or portable...
Otoh it is pretty simple to show diffs in the overall sound of phono cartridges. You could probably even hear a substantial percentage of their diffs using a rather low bit rate MP3 recording. That's not to say that you'd hear them sound as they might in an optimized playback system, but that you'd likely hear a difference between any two brands of cartridge that you might choose.
But all of this discussion is moot. Ed will produce what he does, and we'll see what comes of it. Maybe it will motivate some of you to get into gear and participate. Especially if you would like to see things done in other ways.
Not terribly practical or portable...
Otoh it is pretty simple to show diffs in the overall sound of phono cartridges. You could probably even hear a substantial percentage of their diffs using a rather low bit rate MP3 recording. That's not to say that you'd hear them sound as they might in an optimized playback system, but that you'd likely hear a difference between any two brands of cartridge that you might choose.
But all of this discussion is moot. Ed will produce what he does, and we'll see what comes of it. Maybe it will motivate some of you to get into gear and participate. Especially if you would like to see things done in other ways.
I've sat in Kevin Gray's mastering studio and EVERY digital source recording he played sounded, at best, a bit soft in the top end. It didn't matter if it was printed to tape or came from a software source.
Go look at Rube Goldberg comics. That is digital.
Is he still using the Pacific Microsonics Model 2 DAC? If so, that might explain what you heard.
And when you did this, were the digital sources he had from the best ADCs available in the past few years? Or was it sometime longer ago?
In addition, doesn't he specialize in mastering analog? Does he have a reputation for doing the best digital, or mostly for vinyl?
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Remember, despite the temptation, no politics here.
I have questions also, since I sometimes think I hear these differences and want to know what is behind them.
There are many possible conclusions from the observation, including that all the analog recordings (analog chain?) were bright and the overall sound was softened somewhere? I have heard both superb and lousy analog and digital under very good conditions. When good the digital was free from character, the analog always had a character or sound of some sort.
At 30 IPS you really lose bass. Physical heads are just too small. have a look: Response Curves of Analog Recorders
Similar can be said about comparing film to 4K video. The video is so free of flaws that it has an unnatural quality. The film always has grain and subtle fluctuations and seems familiar. It doesn't mean that film is more accurate, however it can help in the expression of ideas if used with an understanding of its limits and how its flaws can help an image. That's the art side of this game.
However even though a flanger is a nice effect in certain places I DO NOT want all my audio passing through a flanger (this was a real battle I had with an exec at an audio company).
I think the question here is whether opamps have a distinct sound and if they are different. That is really enough of a question. Whether some have a better sound than others becomes more complex and very much an issue in the applications impact on how the opamp operates.
I have questions also, since I sometimes think I hear these differences and want to know what is behind them.
There are many possible conclusions from the observation, including that all the analog recordings (analog chain?) were bright and the overall sound was softened somewhere? I have heard both superb and lousy analog and digital under very good conditions. When good the digital was free from character, the analog always had a character or sound of some sort.
At 30 IPS you really lose bass. Physical heads are just too small. have a look: Response Curves of Analog Recorders
Similar can be said about comparing film to 4K video. The video is so free of flaws that it has an unnatural quality. The film always has grain and subtle fluctuations and seems familiar. It doesn't mean that film is more accurate, however it can help in the expression of ideas if used with an understanding of its limits and how its flaws can help an image. That's the art side of this game.
However even though a flanger is a nice effect in certain places I DO NOT want all my audio passing through a flanger (this was a real battle I had with an exec at an audio company).
I think the question here is whether opamps have a distinct sound and if they are different. That is really enough of a question. Whether some have a better sound than others becomes more complex and very much an issue in the applications impact on how the opamp operates.
One would guess that the digital source would sound bright or harsh if anything. That's the most commonly leveled criticism.
60 fps video has an unnatural quality also depending on what it is / how it's shot. I'm not talking about the TV interpolated "soap opera effect". I actually know people that leave it turned on and prefer it! I really have no idea how...
60 fps video has an unnatural quality also depending on what it is / how it's shot. I'm not talking about the TV interpolated "soap opera effect". I actually know people that leave it turned on and prefer it! I really have no idea how...
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