Tech help.

[pedalguru]

This is the issue:

I put in a good working quad of EL34s into the amp and once the amp warms up they glow red! I immediately shut the amp off to prevent any damage... I tried to adjust the bias pot and it does nothing to prevent this. I measured 2V from the cathode to ground on each power tube!! It should read 30 to 45 mA roughly...

What is the cause of this?

[Andy Le Blanc]

El34 have a differn't pin out than 6l6, right tubes in the right amp?

check that you have bias voltage, check you screen resistors
beyond that you need to give more info.

whats the amp?

[pedalguru]

Mojave Peacemaker. A plexi circuit.

It's really confusing why the Bias adjuster doesn't do anything to the bias of the tubes.

[Reeltarded]

Dood, more info? What did it do before? Did it melt down the other quad?

Sounds like you have no bias at all, bad caps, 10 other things but please at least hint at a little more background, thanks. jees

[ampgeek]

Welcome pedalG!

You mention measuring voltage but say you are expecting a certain current at the cathode. Where and what are you actually measuring?

Cheers,
Dave O.

[roberto]

pedalguru, switch on the amp in stand-by mode.
Check the negative voltage variation turning the bias pot full CW or full CCW.

[Reeltarded]

In a PM he said a tech had checked the amp out after redplating a tube from over bias condition. Amp lost a fuse , fuse replaced, tech claimed it was straight.

the tubes were then replaced and from the previous posts looks like both pairs are plating.

It needs to go to someone better than that tech?

Do like roberto said above and see what the range is. I think it is outside the bias circuit though. Let's see.