Dual Rectifier tube problem

[ScreaminSaint]

A friend of mine who bought my old DR is having some tube trouble. I put Mullard EL34's in it a few weeks before he bought it. The voltage on them as around 33 mV. He was saying that the amp was cutting out a bit at his last gig and he had a severe loss of volume today.

I found out that his volume problem was due to the fx send being close to off. I checked the bias on each tube with a Weber bias rite. Looking at the back of the amp, from right to left, i had them as D,C,B,A. A and B were running around 33mv and C and D were running almost 60mv. we swapped tubes around and got the same results.

Any ideas?

 

[ScreaminSaint]

He brought the amp over again today since i called my tech about it. Sounded like a tube problem. Checked all the voltages of all the tubes and there is one tube that is running super hot. the other three are fine. didn't matter what sockets they were in. the same tube ran hotter than the others.

We checked some 6l6's in it as well and there is one that is running 10mv cooler than the rest. 3 are running around 29mv and the other is running 19mv. Still the same results as well, socket had nothing to do with it.

He's going to get new el34's for it in a few weeks. he's just going to run half power until then. It's still pretty loud.

BTW, we both agreed that el34's sounded much better in a DR than 6l6s. The 34s ran around 35ma. Sweet midrange chunk with them.