How would one go about adding a "Bright" cap to an amplifer thats a bit dark in tone. It's a master volume amp, so would you solder the cap to the master volume pot or the pre amp pot? Also I read it mentioned that soldering a resistor in parallel with the cap would help the treble through the range of the pot, as opposed to the first bit of travel. Could someone explain the theory behind that? Also, what would be as good way to determine ballpark figures for the cap and/or resistor? Thanks.