Problem with loud buzz from amp

[rolandroland]

First time on this forum so: hello all.

I have a fender stage 112 se which made a huge noise and didn't process the sound properly.

I changed a burned resistor (r82) and re-soldered two large capacitors (board location c52 and c53) as one solder location on each capacitor was separated (came loose).

After this fix the amp played amazing: perfectly quiet when not being played and playing was crystal clear: no hum what so ever!

I turned on the amp this morning to play and there is now this very loud hum and buzz which fluxuates. It went from perfect quiet to a large hum over night.

Plugging the guitar into Input 1 makes a louder hum and using input 2 makes a hum but at a different severity.

When I remove the cord from the inputs it is totally silent.

I don't want to bring it into for repair as i am on a budget. I am skilled at soldering boards so I believe I can fix it myself with the right parts.

Any suggestions on what to look for?

thanks in advance.

[txstrat]

When the amp is quiet if no cable is plugged in, the hum is not from the amp.
Did you try a different guitar, cable or even a different room (fluorescent lights can cause hum).

Oh, and welcome to the forum.

[rolandroland]

there is no hum when not connected to a patch cord

I checked with anther amp I have and there is no buzz/ hum.


I believe it may be old (18 year old) filter capacitors as I found open solder joints on two capacitors (c52 and c51) both located on the negative solder connection.

I was going to replace all such capacitors just in case.

Any suggestions on replacing aging capacitors?

[52 Bill]

I was going to replace all such capacitors just in case.

Logically, if the amp makes no hum or noise with nothing plugged in to the amp, the filter caps are not the main source of your problem. If the filter caps were bad or loose, the power amp would be humming all of the time.

Find a schematic for your amp, and see if there is a muting circuit connected to the input jack. Fender did that on some models. If there is one, you may have a bad part or a loose ground somewhere in the preamp section that is muted when the input jacks are not being used.

[Enzo]

And let us not overlook the very possible broken ground connection at the input jack. Check the solder under the input jack closely.