Noisy Fender Amps - - - -

[erich0316]

I own a newer Fender Princeton 65, and a 5 year-old Fender Roc-Pro 1000. The Princeton has an inordinate amount of noise (and I have good, clean, conditioned power) but it is playable. I was wondering if you can shield it somehow (in the "Quieting The Beast fashion)
The Roc-Pro 1000 has serious problems. It recently began making this God-Awful humming, which is the same volume whether you turn the master up, or not, and whether the guitar is plugged in, or not. It is a "Hybrid", with one output tube, and I was wondering if hat could be the problem. I am a decent electronics tech, have all of the schematics, and JUST WANT IT FIXED. Any help I can get would be appreciated. Thanks,

[UnklMickey]

erich0316,

on your roc-pro, that 12ax7 tube is in the preamp section so it's unlikely to be the cause of your problem, besides they aren't using it to provide any gain. they are just using the 2 halves as diodes to clip the signal. first place to start looking is in the power supply. if your rectifiers (cr52~55) check out good, look for an open cap (C71~74) or less likely an open or shorted zener diode (cr56~57).

i'd (almost) bet money that you'll find your problem in the power supply, but if not, give us a shout back, and i'll do a bit more head scratchin'.

on the princeton, i'd suggest first looking to make sure you don't have any component failures causing the hum/noise. next, consider running your heaters on D.C. (at least the pre-amp tubes). after that, if it still aint quiet enough, then start trying auxillary shielding.


happy hunting!

U.M.

[UnklMickey]

Dude!

just about the time i posted, it started to sink in. you said princeton 65, not '65 princeton. your amp is solid state, so forget all that $#!+ i said about D.C. heaters.


i feel like roseanne roseannadanna.


U.M.

[jdtogo]

is the P65 making this noise when you have your guitar plug in . if you unplug your guitar is there less noise ? is your amp by a computer or tv . do you have a good ground ?