help me with my amp

[audiomike242]

so some of you may have seen my post about and old squier amp i found and ended up trying out. well, i went rummaging and found a Fender Princeton 65 DSP. Here's my problem...

I turn it on and its okay, I plug in a cable and it starts to hum. It's that kind of hum that you hear when you have an amp cranked but your not playing anything... so I guess its a hiss/hum. I don't know why plugging in a cable would make it do that, and its not the guitar.

I want to get rid of this 1. because its just annoying. and 2. because i dont need that hum ruining guitar tracks.

I don't think it's the input jack, it seems solid...
Dude that had it before me said it starting doing it a year or so after he got it.

I might dissect it or take it to a shop... but the local shop here likes to gouge you.


HELP D:

[garageband]

I've seen sometimes where some moron has clipped the ground lug off the power cable will do this. Outside of that, maybe get in there and replace the power filter caps (the big ones). Heck, maybe as many of the electrolytics as you can get at.

[audiomike242]

Hmm. I'll have to crack it open. I really like the amp and if I could get rid of the hum it'd save me from talking myself into buying a siccck Vox haha.

Anymore suggestions? Should I just take it to a shop?

[garww]

Beyond what GB says, it could just be internal ground. typical loose wire stuff.

[Freddy G]

The input jack shorts to ground when nothing is plugged in, that's why it doesn't hum.
If you replace capacitors as GB suggests just make sure you drain the big power supply caps with a 100ohm resistor first (after you unplug the amp of course) otherwise you might be in for a little surprise!
Make sure you observe correct polarity with the caps.
tighten all bolts and jacks, sometimes a signal ground path to the chassis is established this way and a loose jack for example will be problematic.
If you are not comfortable with a soldering iron then take it to your repair shop. Gouge? Look at it this way, the guy in the repair shop probably lives in your area and has a family to feed. In order to do that he can't possibly work for the kind of wage people in China got for assembling the thing.