Grateful Dead Music Forum

Do they have to be rebiased or can I just pop new ones in and if I am changing them are there any suggestions on switching them up.?? Thanks in advance
Eric

This info is readily available all over the internet: re-bias the amp after changing power tubes; preamp tubes don't require bias adjustments.

If you get tubes that are matched some people will tell you the amp doesn't have to biased because they should be drawing the same current. However, I always have my amps rebiased when replacing tubes unless the amp is fixed bias. Any decent amp tech should be able to bias your amp in 15 minutes.

I re bias my amps when changing power tubes as well.
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