Now I don't know from potentiometers, but I'm thinking that if they're like any other type of electronic equipment, the quality of the knob is of minimal importance. Not so, it seems, with the Silver Rock Signature Potentiometer & Passive Preamplifier, a device for which special wooden and bronze knobs will cost you $500 apiece—and you'll need two.
I could crack a joke or something, but it's not going to beat out the ad copy that tries to convince you that minute vibrations through the knob axle will cause micro vibrations that affect the sound. Micro vibrations so small, I bet, that they can't even be measured! (Thanks, Oversight!)