sparklesmcgraw said:When working the tubes should always glow blue.
If running in Simul class all 4 should glow, in Class A the two outer ones only should glow.
If the tube that isnt glowing is selected then it may be defective. How old are they and what kind are you using?
SonicProvocateur said:My 60 watter was like this with my EH tubes, but not my STR-425's. It has to do with the tubes themselves and voltage applied. I talked to phyrexia about it, and he said it was normal and that it was probably that the EHs weren't perfectly matched....
Yet again, that tube later popped and burned a screen grid resistor. Maybe early signs of a leaky resistor? I know my amp needed a slight rebias, so maybe its time for some dialing in on yours...
boogiemon said:Thanks for the data point. i've tried a couple different pairs of power tubes w/no change: t he one on the right glows blue, the one on the left doesn't. i've also changed the phase inverter tube w/no effect. i wouldn't care except that this boogie doesn't seem to "boogie" like it should. Even for 60 watt's it seems like it has no headroom. Down low everything is good but turned up in a band setting it's kinda under-whelming.
SonicProvocateur said:boogiemon said:Thanks for the data point. i've tried a couple different pairs of power tubes w/no change: t he one on the right glows blue, the one on the left doesn't. i've also changed the phase inverter tube w/no effect. i wouldn't care except that this boogie doesn't seem to "boogie" like it should. Even for 60 watt's it seems like it has no headroom. Down low everything is good but turned up in a band setting it's kinda under-whelming.
Yeah...im thinking smoke and popped tubes is the next thing to happen...
Might wanna upgrade screen grid resistors (from 1 watt to 3) and rebias.
boogiemon said:
Horizon6505 said:boogiemon said:
Hmm. I dunno then. Have you called mesa?
boogiemon said:i've tried swapping the two power tubes & the pi tube but the tube on the outside always glows blue the inside one does not.
boogiemon said:re-bias? i thought boogies are fixed-bias...
elvis said:Could be a cold solder joint on the bias, or bad socket contact. Or output transformer (I hope not!).
wizard333 said:Blue means the purity of the vacuum isnt great as it could be and there is oxygen in the tube.
As long as it sounds ok, nothing to worry about.
boogiemon said:It's a sixty-watter: only two power tubes. The position on the right (looking from the back) glows blue which I know is ok, but shouldn't both positions do this? I've tried swapping tubes but it's always the one on the right that glows blue.
sparklesmcgraw said:When working the tubes should always glow blue.
If running in Simul class all 4 should glow, in Class A the two outer ones only should glow.
If the tube that isnt glowing is selected then it may be defective. How old are they and what kind are you using?
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