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Hoffman Amps Forum image Author Topic: Marshall Bluesbreaker Bias???  (Read 3932 times)

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Offline plexi50

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Marshall Bluesbreaker Bias???
« on: November 05, 2011, 05:15:17 pm »
Hey guys!! I must be blind and stupid today. Can some one tell me the bias for the Reissue Bluesbreaker using 5881 tubes? *******

Offline shortfuse

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Re: Marshall Bluesbreaker Bias???
« Reply #1 on: November 05, 2011, 11:11:39 pm »
whats your voltage on pin 3?

Offline plexi50

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Re: Marshall Bluesbreaker Bias???
« Reply #2 on: November 05, 2011, 11:29:22 pm »
whats your voltage on pin 3?

I decided to use 6V6 tubes instead. Plate voltage is 426VDC with a -38.6VDC  grid voltage. Ive been reading that this amp supposedly is better suited to the 6V6 tube

The Bluesbreaker schematic shows no grid voltage. I really cant find anything about biasing it online either

I think the only difference between the JTM 45 and the Bluesbreaker was the tremelo

The tremelo has been dissconected. The voltage mixer circuit is now 270K instead of the 470K's that were in it

Also put in a 500pf cap in place of the 100pf cap on channel 1 mixer resistor bypass cap

Probably going to do the same with channel 2 
« Last Edit: November 05, 2011, 11:35:01 pm by plexi50 »

 


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