Tube Amp Archive

I put a new .02 coupling cap between the 12AX7 pin 6 and pin 5 of the 6V6 and no difference. I replaced the 6V6 with a known good one. A weird observation is when I apply power while monitoring pin 3 of the 6V6, it measures 500V and slowly decreases in value and the Cathode voltage on the 6V6 slowly...

The voltage at pin 5 of the 6V6 is approx 2.0Vdc after warm up and as the cathode voltage increases.

Thanks for the reply Stevem - measured across the speaker and I only measure mV... - when I short the tremolo foot switch jack No tremolo is heard. When the short is removed, I hear the tremolo when I increase the Intensity pot. - swapped the AX7 in the tremolo socket and same result. One thing to n...

Repairing this 60's Vibro Champ for a friend and it has a distorted output. I measured the resistors in the B+ circuit... they all measure good. When I turn it on and measuring pin 3 if the 6V6, I'm seeing 405Vdc and as the tube warms up, the voltage drops below 300V. At the same time I'm measuring ...