I have a bunch of 7-pin triodes and pentodes. Time to do weird things to them. I probably should stick a 2.2M resistor between the wiper and ground of the master volume pot to maintain a ground reference for the grid of the power tube in case of wiper failure. The alternative is to hook up lug 3 of the pot to the power tube, and the wiper to the coupling cap, but that would present a variable load to the pentode, which may not be a bad thing for what I'm trying to accomplish here. I got the idea for the optocoupler from a thread from el34world (https://el34world.com/Forum/index.php?topic=24334.0) The tremolo tube will always be on, so there's a separate power node to isolate it from the rest of the circuit. Chassis (10" x 6") drilled and painted.