Fender SuperSonic noise

CSS · September 2nd, 2007, 09:39 AM

On a Sunpersonic combo (1-12), there is a noise that sounds like an AM radio way off channel. This happens only when the amp is "on power", not during standby. When I say lound, I mean un-playable loud. Any clues?

CSS · September 3rd, 2007, 12:48 PM

A bump for my post and to add the following:

I swapped the tubes around from socket to socket, making certain of which went where and to return them to the original locations. This changed nothing. The noise is there with the volume and all controls set to off or on, doesn't matter. It also will let out a very loud POP every 10- 15 seconds.

The noise starts about 15 seconds or so after defeating the standby switch. In standby, there is no noise.

The amp just mad a 600 mile or so trip via UPS but was packed pretty good in styrofoam peanuts.

-Craig

Tremo · September 4th, 2007, 02:36 AM

Sounds like there may be an oscillation or other instability in the output section. You say it does this regardless of the knob settings? Turning any/all knobs has no effect on this sound when it's happening?

First off, is there an AM radio station nearby?

If no radio station nearby, I'd start pulling tubes in order to see where in the circuit this instability is actually happening.

September 2nd, 2007, 09:39 AM	#1 (permalink)
CSS Tele-Holic Join Date: May 2003 Location: Myrtle Beach, SC and Augusta, GA Age: 49 Posts: 832 25 Photos	HELP, Fender Tube Amp noise is SUPERSONIC On a Sunpersonic combo (1-12), there is a noise that sounds like an AM radio way off channel. This happens only when the amp is "on power", not during standby. When I say lound, I mean un-playable loud. Any clues? __________________ "The only difference between me and the audience is the microphone" -John Waite Last edited by CSS; September 2nd, 2007 at 05:06 PM.

September 3rd, 2007, 12:48 PM	#2 (permalink)
CSS Tele-Holic Join Date: May 2003 Location: Myrtle Beach, SC and Augusta, GA Age: 49 Posts: 832 25 Photos	A bump for my post and to add the following: I swapped the tubes around from socket to socket, making certain of which went where and to return them to the original locations. This changed nothing. The noise is there with the volume and all controls set to off or on, doesn't matter. It also will let out a very loud POP every 10- 15 seconds. The noise starts about 15 seconds or so after defeating the standby switch. In standby, there is no noise. The amp just mad a 600 mile or so trip via UPS but was packed pretty good in styrofoam peanuts. -Craig __________________ "The only difference between me and the audience is the microphone" -John Waite

September 4th, 2007, 02:36 AM	#3 (permalink)
Tremo Friend of Leo's Join Date: Mar 2003 Location: Silicon Valley, CA, USA Posts: 3,684	Sounds like there may be an oscillation or other instability in the output section. You say it does this regardless of the knob settings? Turning any/all knobs has no effect on this sound when it's happening? First off, is there an AM radio station nearby? If no radio station nearby, I'd start pulling tubes in order to see where in the circuit this instability is actually happening. __________________ Exposing the CONs. www.myspace.com/59tremolux