I wanted to get a better set of tubes than what the amp kit shipped with. My default tube is the E83CC (https://www.tubeampdoctor.com/…ectronic?number=NN032-SYM). I ordered a balanced tube for the PI of the amp.
However, when it's installed, the amp has an extremely loud humming sound. The amp is still functional aside from this really loud hum. I put this tube in V1 and there was no issues. I've put a standard JJ ECC83S tube in the PI and it works fine. I am able to use E83CC in V1 and V2 without issues, so it seems to be specifically putting an E83CC in the PI triggers something.
Any ideas why this tube cannot work properly in the Phase Inverter? Is there any sort of biasing or something which might cause this issue? Do I need to make changes to the amp to make this tube work in this position? I'm using it in the PI of another amp and really like these tubes.