Originally Posted by jonesy
I still cannot hear any difference in brightness between the two caps when the Tone control is on 10.
Hey Jonesy, I think we need to remember, just because we can't hear the differences (I certainly can't) doesn't mean the differences don't exist. Unless we're all using no-load pots on 10, the capacitor does still form part of the circuit. At the micro level, there is probably a difference in the resultant signal. Just that the difference may not be discernable by many pairs of ears.
And because it's not obvious (or even audible, perhaps except by dogs) it actually may not matter to most, I guess. But that doesn't mean the differences aren't there. And put through different amplifiers, I'm not sure how the results may be, but some amps might actually show the differences more than others.
On a side note, I spent some time putting my electronics engineering hat back on again, and I think I've also realised another reason why cap materials matter. Not just about what I said about discharge patterns and all previously.
I remembered that different materials have a specific property when it comes to frequency bandwidth allowance. Not just a matter of cap values, but the material itself has an inherent low pass frequency bandwidth. Some materials allow more through, and some allow less through. In the case of PIO, I can't remember if the paper is the limiting factor, or oil.
So, a 47uf cap made of PIO will have a different filtering bandwidth as compared to a ceramic or polyproplene simply because the materials differ in terms of the amount of frequencies of the signal it processes.