Super Lead 1959 clone - curious bright cap behavior

[acorkos]

when i solder different bright caps of various values between 120pf and 1000pf between the input lug and wiper of the high treble channel volume pot, i get a strange thump when i move the pot from '0' to '0.5', along with some static noise. moving the cap to the turrets which connect to the same pot lugs via wires, there is no noise....i wonder why?

[jfutral]

Increased solar activity is my guess. Or a cheap pot?

Joe