Re: 474k cap for 500k pots?
A 474k would effectively convert your tone control to a volume control. The first two numbers are "significant digits", 203, 474. The third digit is the number of zeros, that equal the total picofarads. So . . .
203k = 20,000 picofarads = .02 uf
474k = 470,000 picofarads = .47uf
That value would pass all the audio to ground . . . ergo, a volume control. A 473k wouldn't be too bad. Thats a .047 uf.
btw - I believe the "k" and the "M" are related to the voltage rating of the cap. I'll see if I can find the answer to that.