01-22-2013, 11:30 AM
Well, I think it is simply 1) brings the Antenna input closer to Chassis, thus lowering the input signal, when wiper is moved closer to it, and vice versa when away, making it quieter/louder, and 2) changes the 32s' biases (in particular the second one's cathode) by moving them away/closer to the chassis, also changing the gain.