I think we are pretty much aligned. If we split terms into two and for example use 'sensitivity' to describe how much it bothers one and 'acuity' to the level at which it can be detected then I think we can get some markers down.
Acuity is in my mind a fixed function of the ear itself. Sensitivity can be trained and learned. A trained listener might seem to have better hearing when in fact its an enhanced sensitivity.
There is of course the side issue, which is that musical enjoyment may be reduced as sensitivity increases. At the extreme you have on one side, concert musicians with a crappy boombox and audiophiles who only listen to test records and fret over everything instead of kicking back and enjoying the music. Both stereotypes, but with a lot of truth in there.
As I get older I am modifying my system more, yet at the same time worrying less. I hope in another 15 years to get to the level Scott is at in having a large and eclectic* enough collection that its ALL about the music.
*I'll never reach the diversity Scott has, but you need to set stretch goals 🙂
I'm not providing a dedicated solution, I'm merely trying to inform WHAT test people want to run. No use trying to make a test platform until the latter is established.
That said, if we're worried about people gaming a music-based differentiation test, then going to software seems much much much smarter.
Bear I want to remain cordial and friendly and let others do any listening tests, but I have to make a couple of things clear. I have never stated that all op-amps sound the same on the contrary you have stated that all op-amps do not sound the same. I'm happy with the probability that some IC amplifiers could be made that one would have a hard time day to day telling the difference.
Secondly your stated experience has no more credibility or validity than my experience with rolling op-amps in an Adcom pre-amp. We are on equal ground.
Just build a set of unity gain boxes that insert inline with with existing cabling arrangements.
That means a straight throughput box complete with power input and associated ground connection port to be compared to 'suspected' active unity gain boxes.
Of course this means adding one extra RCA-RCA cable in addition to the 'naked' playback system but does not change the comparative conditions.
So, insertion of an outward appearance identical RCA-RCA 'unity qain' box should not change the perceived test conditions and therefore provide untainted test conditions.
The alternate is to incorporate a DIL8 socket and just 'roll' with it.
Dan.
That means a straight throughput box complete with power input and associated ground connection port to be compared to 'suspected' active unity gain boxes.
Of course this means adding one extra RCA-RCA cable in addition to the 'naked' playback system but does not change the comparative conditions.
So, insertion of an outward appearance identical RCA-RCA 'unity qain' box should not change the perceived test conditions and therefore provide untainted test conditions.
The alternate is to incorporate a DIL8 socket and just 'roll' with it.
Dan.
Hearing difference with opamps is application dependent.
Same thing with tubes.
Does a cathode follower output stage sounds the same with same type of tube rolling? Yes.
Does different types of buffer opamps sounds the same with rolling them? no. They are too different.
You can hear the difference in gain stages with same type of tube rolling.
I don't think you can hear much difference if you roll the same opamps in a gain stage. They are using a feedback loop and the whole supporting circuit would basically sound the same.
Opamp rolling is like inserting a different tube type in any amplifier position... yes it should sound the same unless your audio system is compromised.
Same thing with tubes.
Does a cathode follower output stage sounds the same with same type of tube rolling? Yes.
Does different types of buffer opamps sounds the same with rolling them? no. They are too different.
You can hear the difference in gain stages with same type of tube rolling.
I don't think you can hear much difference if you roll the same opamps in a gain stage. They are using a feedback loop and the whole supporting circuit would basically sound the same.
Opamp rolling is like inserting a different tube type in any amplifier position... yes it should sound the same unless your audio system is compromised.
It may seem that way until you get down to the details of some specific design requirements and analyze what happens. See Ed's post #4111 a bit earlier in this thread: http://www.diyaudio.com/forums/everything-else/169484-what-wrong-op-amps-412.html#post4920231 Beyond that, generally speaking, most or all audio systems are compromised in some way. They don't ever reproduce sound with zero distortion.
Also, regarding opamps as buffers, don't they typically use the maximum feedback possible? If you tie the output to the inverting input, that's 100% feedback.
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Little of this rumination matters at all, makes no difference.
Ed is going to make a box.
It will have goesintas and goesoutas.
THEN someone or several people will listen through it, plugged into some system or another.
After that they will report some sort of preferences or critique of the sonics or give both reports.
Ed, it seems most likely, will have already measured the "box" before sending it out so as to assure its proper operation.
After that Ed (perhaps in consultation, perhaps not) will report back (hopefully in a NEW THREAD?).
After that everyone can slice and dice, and maybe we move forward to a second round of tests that takes into account different issues/parameters/test set-ups.
Rinse and repeat.
Then after several more months, continued in this way, an "outer envelope/boundary" may have been drawn around the entire issue in such as way that a better understanding is achieved - or else nothing will be clear, or something in between.
So let's focus on the issues of Ed's circuit, since he's the one who has stepped up to do something... keep in mind this is... only a test
Ed is going to make a box.
It will have goesintas and goesoutas.
THEN someone or several people will listen through it, plugged into some system or another.
After that they will report some sort of preferences or critique of the sonics or give both reports.
Ed, it seems most likely, will have already measured the "box" before sending it out so as to assure its proper operation.
After that Ed (perhaps in consultation, perhaps not) will report back (hopefully in a NEW THREAD?).
After that everyone can slice and dice, and maybe we move forward to a second round of tests that takes into account different issues/parameters/test set-ups.
Rinse and repeat.
Then after several more months, continued in this way, an "outer envelope/boundary" may have been drawn around the entire issue in such as way that a better understanding is achieved - or else nothing will be clear, or something in between.
So let's focus on the issues of Ed's circuit, since he's the one who has stepped up to do something... keep in mind this is... only a test
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Big typo on my part, different tubes rolling in gain stage is the equivalent of opamp rolling
It shouldn't sound the same , sorry. You should hear a difference in all opamp rolling , ceteris paribus
Most of us already did some of these tests, as the circuit is the same and only the opamp changes it is Certain to have a different sound.
Giving how poor todays dac & i/v are I doubt everyone will prefer a certain type of opamps coloration.
A bit earlier in this thread, I mentioned an audio CD with recordings of the same source material through different A/D converters. Although the physical CD which originally cost $45 is out of print, the wave files are now apparently available for download for $5. Using the CD, I heard the difference between some fairly expensive professional converters. I will post the link in case anyone else wants to see for themselves: http://store.payloadz.com/details/112337-music-miscellaneous-3d-adcd-a-d-converter-comparison.html
pos·se
noun
US historical:
a body of men, typically armed, summoned by a sheriff to enforce the law.
BRITISH historical:
the body of men in a county whom the sheriff could summon to enforce the law.
noun: posse comitatus; plural noun: posse comitatus
informal
a group of people who have a common characteristic, occupation, or purpose.
"he pompously led around a posse of medical students"
synonyms: gang, band, group, crowd, pack, horde, herd, throng, mob, swarm, troop, cluster; company, gathering; informal bunch, gaggle, load
"Sheriff Munro assembled a posse of armed men to track down the train robbers"
I kind of like the one about the medical students. Anyway, is it obligatory to disavow the fringe guys?
noun
US historical:
a body of men, typically armed, summoned by a sheriff to enforce the law.
BRITISH historical:
the body of men in a county whom the sheriff could summon to enforce the law.
noun: posse comitatus; plural noun: posse comitatus
informal
a group of people who have a common characteristic, occupation, or purpose.
"he pompously led around a posse of medical students"
synonyms: gang, band, group, crowd, pack, horde, herd, throng, mob, swarm, troop, cluster; company, gathering; informal bunch, gaggle, load
"Sheriff Munro assembled a posse of armed men to track down the train robbers"
I kind of like the one about the medical students. Anyway, is it obligatory to disavow the fringe guys?
Sorry I was thinking a little more frivolous, stinking badges etc. Posse comitatus in the US violates the forums rules on politics.
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He can be part of my 'posse'. At least he can hear differences. I also hear similar differences in IC op amps, and so can Bear. This makes for PROGRESS in audio design and quality.
Not so sure. Progress in that seems to be somewhat stalled, and will likely stay that way until you can prove the claims to the guys who remain quite skeptical. Especially the skeptical guys that make ICs and most commercial audio products.
This is how I relatively recently made an IC op amp evaluation:
I have a 30dB gain input op amp stage in the JC-3. There is NO EQ involved around the IC, but the input signal is fairly low in level, perhaps 0.5mV typically, perhaps 10mV on extreme peaks. The input signal is from a quality moving coil cartridge, playing the best recordings I have, including direct discs from the '80's. This is a difficult, but non-clipping signal source.
Then, I evaluated 3 separate op amps from different manufacturers, that had essentially the same input noise, slew rate, and most other parameters.
One sounded really lousy. Why, I don't know, then comparing the other two sounded OK, but SLIGHTLY DIFFERENT. It was a toss-up between the two, so I chose the less expensive one. However, in future, if we for some reason can't get the less expensive one, I would use the more expensive one, or run the test again with other, newer op amps, if necessary.
Then I compared the sound of JC-3 phono stage that has essentially the same system topology as the Vendetta Research in my CTC Blowtorch, with essentially the same EQ parts, and power supply buffers, showing that the JC-3 was comparable, but not quite as good. Everything else was the same:The same Blowtorch line amp, power amp, and loudspeakers (Wilson) Could I have imagined things possibly? I doubt it.
Note: Look at Fig 7 of the paper. That is what I drive the IC with, worst-case.
I have a 30dB gain input op amp stage in the JC-3. There is NO EQ involved around the IC, but the input signal is fairly low in level, perhaps 0.5mV typically, perhaps 10mV on extreme peaks. The input signal is from a quality moving coil cartridge, playing the best recordings I have, including direct discs from the '80's. This is a difficult, but non-clipping signal source.
Then, I evaluated 3 separate op amps from different manufacturers, that had essentially the same input noise, slew rate, and most other parameters.
One sounded really lousy. Why, I don't know, then comparing the other two sounded OK, but SLIGHTLY DIFFERENT. It was a toss-up between the two, so I chose the less expensive one. However, in future, if we for some reason can't get the less expensive one, I would use the more expensive one, or run the test again with other, newer op amps, if necessary.
Then I compared the sound of JC-3 phono stage that has essentially the same system topology as the Vendetta Research in my CTC Blowtorch, with essentially the same EQ parts, and power supply buffers, showing that the JC-3 was comparable, but not quite as good. Everything else was the same:The same Blowtorch line amp, power amp, and loudspeakers (Wilson) Could I have imagined things possibly? I doubt it.
Note: Look at Fig 7 of the paper. That is what I drive the IC with, worst-case.
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At least he says he can hear differences, which seems to be all you care about. Keeps the agit-prop mill going.
Doesn't seem implausible to me that you heard some difference. However, let me ask you this: Have you ever heard someone make a claim about hearing some difference in something that seemed unlikely to you? If so, and if you happen to remember the details, I would be interested in hearing what it was.
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