Fender Princeton 65 - Reverb/Drive hum

[progrmr]

I just picked up a used Fender Princeton 65, the SS model. Pretty nice tone but I didn't notice it when the guy was showing it to me, but when I turn up the reverb past 1 or use the "overdrive" channel with the drive set over 1 I get a very noticeable hum that is quite loud depending on the volume. Is this normal? It's pretty loud, but not harsh.

Also this seems to be another fender amp that gets extremely loud very quickly - IE turning up the volume past 2 (not 2 o'clock lol!) the amp is very loud. I'm also wondering if the fact that I have the open back set pretty close to the wall as I don't like my cats crawling around in there - I figure the sound isn't being allowed to go out the back as designed and is being pushed out the front making it seem louder..??

[Spudman]

If it has a tank reverb make sure all the plugs are firmly seated on the tank. If that doesn't do it you might want to check the springs in the tank and make sure none are broken. Generally if a chip controls the reverb circuit (Peavey Classics) then it either works or doesn't. Try different guitar cables as well. Eliminate signal input issues first then go into the amph to troubleshoot.

[FrankenFretter]

I just got one of these for free, and I have the same issues. It gets horrible feedback when the reverb is on. It takes a few minutes to develop, but when it does, the only way to get rid of it is to turn the reverb all the way down. I think this is the same problem that a lot of small chassis combos have, and it has something to do with the speaker vibrating the reverb tank. My thoughts are to possibly install some rubber bumpers between the tank and the enclosure, and maybe a layer of foam on top of the tank to deaden the vibration. Will it work? Maybe. If it doesn't, I still got my money's worth out of this amph.

[progrmr]

Well I paid $125 so crap!! Lol!

I just took mine apart looking for blown caps - it's very clean inside, caps are good. Circuit board is stamped 1999 but I can't tell if that the year of manufacture.

Some threads I've been reading say its just a noisy amp...it's pretty noisy for sure, but only w/ the reverb and distortion applied.

[FrankenFretter]

Well I paid $125 so crap!! Lol!

I just took mine apart looking for blown caps - it's very clean inside, caps are good. Circuit board is stamped 1999 but I can't tell if that the year of manufacture.

Some threads I've been reading say its just a noisy amp...it's pretty noisy for sure, but only w/ the reverb and distortion applied.

Although I haven't tried it yet, this amph apparently takes pedals well. I plan on taking advantage of the effects loop and trying some pedals out this weekend. You're right about this thing being LOUD though...it's damn loud. I'm thinking about an L-pad and a panel to seal off the open back. Hope you get yours figured out soon. If I do the rubber grommets and foam and it works, I'll let you know.

[progrmr]

Thanks - I actually just tried my tube screamer through the effects loop....hum. I put it before the amp though and left it out of the effects loop an it works fine as long as the reverb isn't on and through the clean channel of course.

[FrankenFretter]

Yeah, I think dirt pedals don't do well through effects loops. They're meant more for time and/or modulation based effects, I believe. Of course, if you use the dirts straight in, and the others in the effects loop, that's a whole lot of cordage laying around to trip on... ;)

[Ch0jin]

Are we talking 60Hz hum?

If so, it could still be a cap issue. Dry jointed filter caps are WAY more common than "blown" caps in an amp of that vintage, so looking at the solder joints, or just reflowing them anyway would probably be more effective than looking for deformed caps.

The quick test for dry jointed filter caps though is simply the bash test. Turn it on, turn it up to the point where you hear the hum and give it a solid thump. If you hear the hum cut in and out, bingo, dry joint. I just had the same thing in my old 90's Peavey.

[progrmr]

I just disconnected the reverb tank and the hum is still there (thinking it's just that Fender amp hum lol) but at least while I'm playing I don't get all that racket/noise that must've been caused by the reverb tank.

Picking up an EHX Holy Grail tonight just in time for my Classic Player Jazzmaster on Thursday :)