Well, I am up for a little while, still somewhat but getting better from the cold.
Yes, Nick, I have performed some similar testing when designing my 10A, and 11A line preamplifiers some decades ago. I used the results when designing my SET amps, and PP amplifiers.
Besides sonic testing, I had to also consider, resistance value/construction, dissipation rating, and even voltage rating. This for maximum durability and minimal breakdowns.
Capacitors deviate, sonically, much more than resistors. And due to physical construction details vs value of capacitance, what may be accurate in one value may not be accurate at another value.
The above may not make sense, but consider that a larger value coupling capacitor can sound leaner than a smaller value capacitor, due to length to width ratio differences.
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I was not able to obtain perfect accuracy in my 11A preamplifier until I used the more accurate sounding parts. I had thought the 10A was perfect, but found slight differences in output vs input via special, proprietary listening tests.
I am all for it, setup a special rig and obtain your own conclusions.
That is why one rarely ever sees a 10A or 11A up for sale. Why change?
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When I see the need for rolling different power cords, that indicates to me that the power supply is not designed properly. I guess you could say that my preamplifiers have built in conditioners to absolutely minimize power cord influences. But that costs money. But it also means that the power transformer, rectifiers have no effect on sound as well.
My PP amps are not absolutely perfect since physical size was a little limiting. However, power cords still have minimal effect.
My ICs have also been listening tested, via special arrangements, for accuracy in absolute terms.
The result is a vertical type system, where I designed the phono stage, preamplifier stage, amplifier, speakers, interconnect cables, and speaker wires. No need for me to roll power cords, although I had to test, when designing, and no difference occurred.
I have the speaker xovers to the point that I am adjusting the zobel resistance by several millionths of an ohm, and clearly perceivable.
The result is a reproduction that is absolutely astounding to me, and others. However, I have to remember that the recording is 50%, half, of all the electronics used from recording thru playback. So quality of recording is extremely important, and often questionable.
Another thought, when testing the 11A, I might go through 20 cds, and finally find one song that the 11A was slightly off. So I had to tweek the 11A, and recheck the entire cd collection again.
The point is that some songs are more critical, and better for checking accuracy than other songs.
cheers
steve