Tube Amp Archive

A voltage survey may be helpful. VDC to the chassis common at every anode, grid and cathode, and the can cap terminals. Tomorrow the plan is to work on the amp, so I'll post the voltages as suggested, as well as trying the amp without the preamp 12AX7 installed as Martin stated. Thanks very much, I...

Is the hum 60/50 Hz or 120/100 Hz? That will identify the hum source as pre- or post-rectification. The lower frequency is what you get when you touch the open guitar cable tip. What happens if you pull the first 12AX7 (preamp tube)? What happens if you pull the second 12AX7 (trem oscillator tube)?...

Hello, 1st post here. I'm building a Mojotone Vibro Champ kit and as I kind of expected with my first guitar amp kit, I've hit a snag and need some help! Thanks in advance to anyone who wants to chime in. This has been a learning experience for me. I've built a K12 stereo tube amp kit that I use and...