Hi all, new to this forum. I was wondering if 2 OPT Transformer of the same brand can be wound opposite or the wires can be opposite. OK, So I ordered 2 OPT from Edcor and after finishing my build (Pete Millet's 20w Engineer Amp), fired it up with no unusual noise, no smoke etc. So everything's fine, voltage measurements, bias etc, until I hooked up a pair of speaker and cranked up the volume slowly ( I added a Pot to control the volume). About halfway I started to get distortion from one of the channels (like oscillating noise, and speaker vibrating uncontrollably. Immediately turn volume down and it goes away. Check everything over and seems to be fine. After a couple of e-mail exchanges with Pete, he suggested that I reverse the plate wires on the channel that causing the distortion and sure enough it solved the problem. My question is, did I do something wrong on the board for it to be reversed or did Edcor sent me a OPT wired wrong? Amp is running great, but I want to know what happened if anyone can shed some light on this. Thanks