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burnt out a tube?

Live sound reinforcement, running PA's and general amplifier/amplification questions and discussion.

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Postby jason brann » March 30th, 2011, 6:18 am

i hadn't used an amp in a while, and when i turned it on today, it seemed like it was quieter than i remembered it. looking inside, one of the tubes was glowing less than the others, but it's still on a little. did i burn it out? is there a way to check for sure? the thing is, i also seem to be losing a lot of volume going through the pedalboard as opposed to straight into the amp, which i didn't notice before. tone loss, sure, but not volume loss. what's going on?
jason brann

Postby ZenMonkey » March 30th, 2011, 10:47 am

Hey, you probably could use a re-tube. If you haven't re-tubed the amp in a few years and you were using it somewhat regularly it could definitely benefit from a re-tubing. Your tone will be enhanced by new tubes also. You can exchange that one single tube for a new tube if you're trying to save money. This can't be done for power amp tubes though, they're usually the larger set, or quad, of tubes. Those have to have the biased matched correctly together.
The pedal problem is probably that one effect isn't getting the correct power supply, a patch cable isn't plugged in all the way, or isn't working altogether.
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Postby cnev » March 30th, 2011, 11:15 am

they eventually do burn out. If it was a power tube then yea I would expect some loss of power not sure about the smaller pre-amp tubes though.

Not sure about signal loss through the pedal board but if the volume increases when directly plugged into the amp I would think your losing it someewhere in the pedal board.
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Postby jason brann » March 30th, 2011, 2:42 pm

the problem seems to have gone away on its own. i did check all the patch cords, and who knows, that may have been it. perhaps one of the (its a preamp tube) just glows dimmer.
jason brann

Postby Moonrider » March 30th, 2011, 7:43 pm

jason brann wrote:i hadn't used an amp in a while, and when i turned it on today, it seemed like it was quieter than i remembered it.

If an amp's been unused for a while, it may take time with current running through them for capacitors to reform. Since it seems to have "fixed itself," this may have been what happened.
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