The Amp Garage

6v6X1 with 800 ohm bias resistor and your voltage readings provided, I come up with approx. 74%. This is pretty cold for a cathode bias circuit. The more you drive the 6v6 the sooner grid current starts and moves toward cutoff. Can you move more toward 500 ohm. Voltages at each pin of both tubes may...

So incorrect thinking is still thinking. Right.. I agree we don't need to hear voice of America through the amp :D . And without the second 68k r to form a voltage divider there would be no signal attenuation. I still am used to seeing this value dropped to33k-47k or less on a single input circuit. ...

Thinking again.

with v1a, v1b parallel. your config is same as guitar in hi on one channel and junmper to the other channel.... I would have to experiment with that. Maybe clip in another 68k in parallel?

k... I'll stop thinking now

Good to hear! Hows it sounding?

Just thinking here... A single 68k grid resistor would give you a traditional low input level. If you use a single 33-39k, you would get the high input level. With a 1M input resistor tip to ground on the jack.

Congrats finding your hummmm!

60hz or 120hz?
Do you have a heater center tap?

That is strange indeed. did you re flow that solder joint. Is there bias voltage on the resistor leg on the supply side up close to the body of the resistor?

On the phase invertor, check your resistor color code multiplier... 100r, 1k, 10k, 100k(brown/black/yellow)? Verify with DMM. Its under the wire so I can't see it in the picture. On the bias, IMO, suspect that the zero volt leg is shorted to ground or the 220kr is open. What resistance reading do yo...