I was being facetious; but my point was that for audiophiles, you shouldn't need to be disassembling components in order to tell the difference between systems.
Sure, if you can notice a difference, then go ahead and track down where it is coming from. But if you start from the wrong end (i.e. the 'AD744 has higher noise and higher offset voltage') then you should stop and question your actions, IMO.
Except that it's only one component of many in a system. I doubt there would be a measurable performance difference between a standard formula 1 car, and one which has had it's carbon fiber steering wheel swapped out for an aluminum one. But making a lot of small, nearly immeasurable changes can result in noticeable differences.
Certainly, in the case of racecars if two components differ only in weight, we can infer in what ways this should affect the performance. With audio it's not quite as clear (to me). Is there a measurable difference in the signal between using copper and silver wire? I don't know. But if we know that one component has measurably higher noise, that seems like it has the potential to result in a "cleaner" signal.
However, without going too far down the rabbit hole, I generally agree that in the end the important question is, "does system A sound better than system B".
Nope, we are talking about replacing the engine for one of a completely different model.
Those amps and a very small number of resistors and capacitors are the first stage of amplification of an equipment. They are the biggest source of noise, by a couple orders of magnitude. If you can't tell the difference once you change them, it's because the difference is not relevant (and for audio systems, it's completely irrelevant).
It's hard to notice subtle things without an A/B test, it might just be that quiet parts of certain songs just don't sound as good.
For something like this you would want to measure the noise levels, not make assumptions about audiophiles being wrong; they're only wrong a significant fraction of the time.
There's no reason for an audiophile to test if the part is genuine. They would need to buy a "genuine" part to compare against, but that presumes knowledge about the original part being fake.
The difference in noise is readily measurable. I've done op amp based design for commercial products, including an audio product for my side business. (n.b., it's not targeted at the "audiophile" market). I've measured the noise of dozens of op amp types for a specialized application. Impressively, the measured noise performance typically doesn't stray very far from datasheet values. You can measure it with a few dollars worth of parts, and the audio input of your PC.
Now, it's not a slam dunk that every application should use the quietest chip. Noise trades against some other factors such as current consumption. And of course from an engineering standpoint, cost matters too.
> On the other hand AD744 has higher noise (3x) and higher offset voltage (0.5mV vs 0.1mV).