It works, but loud 120 Hz hum
I looked at Doc's missive on noise, shorted the inputs, tried a cheater plug, and concluded it must be a cold solder joint in the power supply so reflowed every soldered connection I could and no luck
I'm using a pair of regulator boards to power the 71A and I am fairly convinced this has something to do with it, but what I am unsure. I've consulted with the creator of said boards but he is as much at a loss to explain it as I am. The regulator board consists of full wave bridge with Schottky diodes, lots of filter capacitance, a LT1085 regulator, with adjustable voltage output. There are optional pads on the board for a common mode choke which I am using. It sounds very good if I turn it up loud enough to drown out the hum
Your help is greatly appreciated and needed.
Robert Lees