Tube Amp Archive

I'm saying you might have AC mains voltage shorting to the chassis of your amplifier. It could be a faulty power switch or the power transformer. If that's the case be very careful with the amp so you don't electrocute yourself. The problem with isolation transformers and isolated variacs is that y...

Okay. Inside the variac I don't fully understand what I'm looking at so I've attached some pictures--happy to take more if that will help. Three wires come in from the variac power cord, go through a switch, and then into the variac main coil with a meter in series. There is also a thin black rectan...

Thanks for all the help guys. To update, I just checked the variac and RG is on to something. It's showing an open ground on its output socket. I can probably fix that myself and then I'll report back. RG, I have read and saved your whole article. Lots of good method in there for a new guy with just...

I could use some help figuring this out. My first build is a Bell & Howell projector amp converted to a guitar amp. It's a 6V6 push-pull with a 5Y3 rectifier, 6SJ7 pentode first stage and a 6SL7 dual triode driver/PI stage. I was shooting for something like a Fender Deluxe and used the original Delu...