Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Stevewdewitt on December 10, 2016, 05:08:29 pm
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Hello all,
I have gotten my hands on a pile of pcb boards from the now defunct Speedster amp company and I have a completed speedster and I am trying to source the parts. There is one part on the board that I think is a variable capacitor but I am not sure. See the pics. Any help is greatly appreciated. These are cool amps and I would like to build 2 or 3 of them. I have 30 boards.
Thanks
Steve
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That looks like a bias pot to me.
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2 leads or 3? 3 would indicate pot, 2 a cap. appears to be 3 but can't really see
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Remove from board and check it with an ohm meter.
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Remove from board and check it with an ohm meter.
that is a good idea. I was hoping I wouldn't have to do that. The amp that I took the pictures of is a working amp. It isn't mine. I don't really want to damage anything.
The component has two legs NOT three. It is between pin 9 and pin 2 on a 12AX7 reverb recovery half.
I may have to take it off the board. Thanks for the suggestion.
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between pin 9 and pin 2 on a 12AX7 reverb recovery half.
heater to grid variable cap? can you verify, or tell if all the 12XX7's pin 9's are "common"
EDIT it appears the next tube "left" (artist left) is common
The amp that I took the pictures of is a working amp
are your 30 boards unpopulated?
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heater to grid variable cap? can you verify, or tell if all the 12XX7's pin 9's are "common"
are your 30 boards unpopulated?
the 30 boards are unpopulated. What do you mean by "common"
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the pic shows what I was looking for, the "cap" is connected to all pin 9's of the tubes (common)
my uneducated guess is it's some sort of "humbucker" for reducing hum.