I just completed assembly of the S.E.X. 3.0 w/o c4s. It's almost working as expected. The left channel has a slight buzz that changes with the volume.
Oddly it does not simply increase with volume. With no source playing it gets louder until about 3/4 of maximum volume then drops off almost completely beyond. It is not a linear increase in buzz. It has a distinct peak in loudness right before going away.
I read a comment about the Crack amplifier and was wondering if the same could be said about the S.E.X. amplifier. There is very little in the amp before the volume control. I've checked / reheated the soldering on the input jacks. I can/will do the same for the soldering on the pot, but the connections look good to me.
Your hum has to be entering before the volume control; either the source, cabling, or wires from the jacks to the potentiometer. If it was in the circuit, then the volume pot wouldn't affect it.
https://forum.bottlehead.com/index.php?topic=9716.msg90393#msg90393I've also swapped the tubes and the buzz stays on the left channel, so it's not the tube. Any ideas what to check? All voltage, resistance, glow checks pass perfectly.
