Drive issue on a 2-chann Triple

crivat · Mar 29, 2011

Hi there. I've got a problem with my dear old 2-chann triple. Namely, as I switch for the red (everything is set on normal) there is no drive present and the overall volume is very low. The green works fine, but the red has no distortion whatsoever. First time I had this problem I took a peek inside the amp and saw that V5 was not lit. Put another 12ax7 in V5 and everything was great again. Two days and one rehearsal later, the same problem appeared.

This time all tubes were glowing, but no friggin' drive present on red. As I kept on switching between the channels, each time i went from one to the other, some sort o louder pop came through the cab, just as the switch clicked. Should I change all the tubes in V1 through V5 or it's something wrong with the internal switching (LDR' or something).

Thanks guys. The amp is rather old, built somewhere after 91.

etrium · Mar 30, 2011

I don't think you should change the premp tubes because I think that if there was a problem with them, then the orange channel should have problem too seeing that red and orance channel share all five preamp tubes...
Does the orange channel distort properly?

crivat · Mar 31, 2011

i've tried modern orange and it seems to be just ok. as i was testing again the head, all of a sudden the red was ok once more. after playing for some 20 minutes, it stopped distorting. i cranked the master up to a level which in normal conditions, would have been painfully loud, but the volume was rather low, and with no drive. after turning back the master, i went allt he way up with the gain and as i reached full throttle, the drive came back. it's starting to be weird.