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Hi. I've just bought a 1992 Peavey Bravo. I am considering replacing the valves but am told it needs rebiasing if I change the power amp valves. Is this true and, if so, how do I do it ?
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Generally speaking, Peavey does not make the bias adjustable on there amps.
And this is the case with the Bravo.
PEAVEY BRAVO 112 SCH Service Manual free download, schematics, eeprom, repair info for electronics -
Does that mean it won't need rebiasing if I replace the EL84's with a decent matched pair or that it can only to be done by a Peavey service engineer - which sounds daft ?Originally posted by Jazz P Bass View Post
DaveComment
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That means that the amp has been set up so replacing the output valves can be done in most cases without rebiasing.Originally posted by Apache Dave View Post
When you replace the outputs, just monitor them at first to see that the amp sounds good, and that the tubes do not get so hot that the center metal elements start to glow red from too much current draw. If there are any problems shut off the amp and figure out why.Comment
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First of all, the 'bias' is not that critical of a setting.
IF there is nothing wrong with your Bravo amp, a new set of tubes can be thrown in.
The two extreme cases:
1: you buy a cold set of tubes & there will be a noticable crossover distortion.
2: you buy a hot set of tubes and the amp pulls more current than normal & it will get hotter than normal.Comment
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The amp is designed not to need adjustment. Almost any set of EL84s you throw in there will find themselves at a reasonable level of bias, no effort required.
And if that were not enough for you, they don't even need to be matched. Grab two EL84 and stuff them in. The factory certainly doesn;t bother with matched tubes. Much as we might like and even prefer matched tubes, they are not a necessity.Education is what you're left with after you have forgotten what you have learned.Comment
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