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FDP Forum / Fender Amps: 1985 - Current / DRRI Chasis Jack



Oct 13th, 2016 07:28 AM   Edit   Profile   Print Topic   Search Topic

Last night, while checking things I noticed for the first time an empty, chasis-mounted 1/4" jack socket near the transformer - which puts it pretty much under the Intensity pot.

Maybe I should already know this, but can someone explain the purpose of this jack, please?



on the rhine

Oct 13th, 2016 04:05 PM   Edit   Profile   Print Topic   Search Topic


I´m pretty sure this is the "entrance" to the bias-adjustment-pot.
It´s not an "empty" socket - it just looks like it ;-)

You put in a screwdriver to turn the pot and vary the bias of your output-tubes.

cheers - C.

Te 52

Laws of Physics

strictly enforced
Oct 13th, 2016 04:55 PM   Edit   Profile   Print Topic   Search Topic

Yeah, shine a flashlight in that hole and you should see a screwdriver slot.



Dec 3rd, 2016 12:47 PM   Edit   Profile   Print Topic   Search Topic

Thanks, guys - and my humble apologies for the belated response to yours.

I do appreciate your help.


United States

Dec 3rd, 2016 11:27 PM   Edit   Profile   Print Topic   Search Topic

Questions are good rmfrance :) I was completely new to tube amp maintenance just a year ago, learned alot...due to trying to mess with my amp, but none-the-less got comfortable maneuvering around my amp, and testing basic things.

FDP Forum / Fender Amps: 1985 - Current / DRRI Chasis Jack

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