In my limited experience, I can definitely hear a difference in type of cap used--at least in some circuits and certain positions within those circuits. Perhaps, these caps have inherently different qualities other than capacitance, such as internal inductance (as you pointed out), which may be a result of different manufacturing techniques or materials employed by their respective manufacturers, etc. In which case, both premises could be equally true.tonestack wrote:I will believe you when you show me spectral analysis plots from the same amp using two different sets of caps that have the same exact measured values. Any difference that cannot be measured doesn't exist. The difference is merely the result of acoustical phenomenon known as perceptual accommodation.Bob-I wrote: You just opened a can of worms... Many of us have done tests on a variety of cap types and brands and find the it makes a significant difference in these amps. Even the orientation of the cap makes a difference. Some folks go so far as to use one type for the bass cap, and a different type for the mid cap.
Yep, there's a difference.
The orientation of a film-and-foil cap matters because the outer foil acts like a shield; therefore, it should be connected to the low-impedance side of the circuit to reduce coupling.
Anyway, it seems that half the fun is to find the best combination of ingredients, regardless of measured or unmeasured differences, to conjure the "magic" in the tonal potion that is each amp I build. Frankly, I don't really care why I like one cap over another, or whether others can perceive it. I just recognize they are subtly different and wish to learn how to use them to properly season my tone soup.