MKII with bias adjsutment pot from the factory???

[Wally]

How many of you have seen this? I jsut had #3104 open and there is a small, blue adjustment for the bias over on the board where the bias caps are. IT looks factory....about 5/16" in diameter and has a high ratio of turns to change in voltage. Just wondering.....

 

[dodger916]

As pointed out to me by Ed (Boogiebabies), my C+ (upgraded from Mark IIA # 4027, well before my ownership) has the same pot. Not sure how it got there, but it might have been added at the time of the upgrade. The upgrade also included an output change from hundred watt to Simul.

 

[Wally]

Dodger916, thanks for the reply. The thing about this amp is that it has never been back to the factory, and I do believe I am the only person to have opened the amp up. I know the original owner. IT was only retubed while he had it. When he sold it to a friend of mine, we recapped it. Great amp...it now lives with its 3rd owner....a young fellow of 17. LUcky guy.

 

[Boogiebabies]

It's most likely stock from the factory. They used small blue trimpots for a while.

 

[Wally]

Thanks, TR. I knew that it had to be factory...it is just that I had always read/heard that Boogie
amps did not have adjustable bias. Exceptions to every rule???