Static on a fender twin PI

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martin manning
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Re: Static on a fender twin PI

Post by martin manning »

Curranproducer wrote:do you mean the 100k' that feed the plates on all the preamp tubes?
Those would be the ones. Use 1W for the 12AT7 PI plates like Steve says; 1/2W is enough for the 12AX7's.
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Re: Static on a fender twin PI

Post by pdf64 »

Did you get rid of the master volume (as part of the BFing process)?
One of those versions have a bright cap on a tap from the master, http://schems.com/manu/fender/twin_reve ... _schem.pdf and on one amp I traced an annoying crackle to that, ie remove cap and crackle gone. I guess it may have been an intermittent connection on the tap terminal, but it sound better without the bright cap.
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Curranproducer
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Re: Static on a fender twin PI

Post by Curranproducer »

no the MV is still in there BUT I did not replace the cap maybe hat would be a good thing to do?
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Re: Static on a fender twin PI

Post by Stevem »

Yes!
Just to confirm, you did try a different tube in the PI right?
Just yesterday I was moding a guys Blues deluxe and installing a 12ay7 in the V1 spot and I have never heard a more noisy taking a shower like tube in may life!!
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Curranproducer
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Re: Static on a fender twin PI

Post by Curranproducer »

yeah I flipped a 12AX7 into it 1st thing out of lazy ness!
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Curranproducer
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Re: Static on a fender twin PI

Post by Curranproducer »

OK I swapped out the 82K,100K, and the 220K resistor in the PI, as well as all the 100K resistors on each of the 12ax7 plates. nothing got the crackling out of there until I replaced those 220K's. so now the crackling seems to be gone. We shall see as I am going to burn this in for a day or so!
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