Hey all, I was bored one day and decided to make a 5f1 type amp from scrap I had laying around. Basically the same as the weber 5f1 schem here. Except using a solid state voltage doubler (delon circuit) because I didn't have exactly the right transformer. This gives a plate voltage of ~310 VDC for the power tube. So when I put it all together I plugged it in and, Yay there was sound! Unfortunately the sound being made was really awful! Like it would be completely quiet until you hit the strings really hard and then it would come out really distorted and nasty sounding and then fade away with a farty sound. So I whipped out my scope and signal gen and I traced a perfect sine wave through the preamp section, all the way to the input of the power tube. When measuring at the speaker jack (with speaker connected) unfortunately I got this: Well it doesn't look good to me so I was wondering what might cause this? I think I've eliminated the preamp section as a culprit. Does this sound like the bias for the power tube is completely messed up?