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Post subject: 65 Princeton reverb reissue hum problem
Posted: Wed Oct 16, 2013 8:53 pm
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Hi all,
Mi just bought a 65 Princeton reverb off eBay and it has a bad hum when the reverb is turned up passed 3. The noise builds almost like it's feeding on itself. I pulled out the bag that holds the reverb tanked and laid the tank with the cardboard on the carpet next to the amp and the hum was gone. Does anyone know any fixes for this? Thanks for your help.


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Post subject: Re: 65 Princeton reverb reissue hum problem
Posted: Thu Oct 17, 2013 1:46 am
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Joined: Fri Feb 05, 2010 4:31 am
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Location: Province de Québec, Canada
Unplug and plug the four RCA connectors from the amp and from the reverb tank . This may clean contact if bad . Better with contact cleaner but if you do that few time could be alright.

Also a defective 12XX7 tube ? I don't think so , but never know.


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Post subject: Re: 65 Princeton reverb reissue hum problem
Posted: Thu Oct 17, 2013 1:55 am
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" The noise builds almost like it's feeding on itself. "

Sounds like a microphonic 12AT7 reverb driver and/or 12AX7 reverb recovery tube. Try a different 12AT7 and 12AX7 and see what happens.


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Post subject: Re: 65 Princeton reverb reissue hum problem
Posted: Thu Oct 17, 2013 5:12 am
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Thanks I'll give it a try. You don't it's caused by the speaker vibrations?


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Post subject: Re: 65 Princeton reverb reissue hum problem
Posted: Thu Oct 17, 2013 3:30 pm
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Is your reverb tank is in a " tolex " pocket . ?


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Post subject: Re: 65 Princeton reverb reissue hum problem
Posted: Fri Oct 18, 2013 7:04 am
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It's in a vinyl bag with carboard under the tank. I put a small towel under the bag at the bottom of the cabinet last night and it solved the problem, so its not a tube or a wiring problem. Not sure I want a towel in there...


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Post subject: Re: 65 Princeton reverb reissue hum problem
Posted: Fri Oct 18, 2013 9:05 am
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Try a ½" sheet of foam rubber, cut to fit.

Arjay

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"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


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Post subject: Re: 65 Princeton reverb reissue hum problem
Posted: Sat Oct 19, 2013 1:43 am
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Retroverbial wrote:
Try a ½" sheet of foam rubber, cut to fit.

Arjay



Is it problem with reverb tank ? Transducer too loose ? I read somewhere ( Weber Books ? ) t put some tootpick to keep transducer from moving .

I find something here;

http://books.google.ca/books?id=fvUVBP3 ... se&f=false


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