Grateful Dead Music Forum

A place to talk about the music of the Grateful Dead 

 #90370  by gdrfk1990
 Sun Dec 05, 2010 10:34 am
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
 #90374  by tigerstrat
 Sun Dec 05, 2010 12:44 pm
This info is readily available all over the internet: re-bias the amp after changing power tubes; preamp tubes don't require bias adjustments.
 #90477  by sants
 Tue Dec 07, 2010 12:03 pm
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.