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Biasing signal tubes on a tube power amp/Quicksilver M120

Took possession of a new pair of Quicksilver M120 power amps with the KT150 tube upgrade a few weeks ago, am in the process of break in with about 70 hours so far. About 30 hours in I noticed that a 12AU7 tube had started to flare up when that amp was turned on so swapped that tube to the other amp and it followed the tube, I contacted Quicksilver and he told me that this is not a concern but to please switch that tube back to it's origional amp as the amp was biased for that specific tube, now my question is if I wanted to tube roll these 12AU7 or 12AT7 tubes am I out of luck and what happens when it is time to replace them as they wear out, are my tube rolling days over or are they just limited? What say you?
tooblue
tubegroover
2,320 posts
 
There is no biasing required for the small signal input and driver tubes. 



seikosha
218 posts
 
There is nothing in the manual for that amp about having to bias the input tubes.  Perhaps the output tubes would need to be biased when the input tubes changed and that's what Mike was referring to.
audioconnection
1,271 posts
 
   (((You may want to double check as I do believe i read in another thread that the Quicksilver amps do need the small signal tubes ))

  Balance adjustment for the small tubes should be done by a tech
  using DC voltmeter.
 Best JohnnyR
   
tooblue OP
1,922 posts
 
@seikosha , @yogiboy , For clarity on my original post, I used the word bias when referring to the 12AU7 and 12AT7 tubes on my newly acquired Quicksilver M120 amps when the term balanced should have been used. 
a_shah's avatar
a_shah
53 posts
 
@tooblue Did you figure out if you need to balance the 12AU7 on the QS-120 ?
I just purchased a pair of QS Mono 60 from QuickSilver ( not on the Website yet)
I was wondering if i could tube role the 12AU7 without balancing ?
A_shah
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