79 50 watt JMP low volume

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Mars Hall
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79 50 watt JMP low volume

Post by Mars Hall » Tue Jan 10, 2017 6:09 pm

Howdy all, It's been a long time since I had a Marshall on my bench. I'm looking for a layout that includes voltages, so I can find out why this low volume situation is happening. The owner said it was working fine until he tried mounting it in a single 12 combo cab.

Also, it currently has KT88 tubes in the power section and he wants to go to EL34s. Will the bias resistor need to be changed?
"You just slide a bottle up and down til what you want out of it comes out. You just slide away at it til you've got it down." Duane Allman

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