Amp noise

[WashburnBass]

I've got a Kustom KBA65 that ever since i got it, it has been making a weird noise, it can be fine and then all of a sudden it comes in, kinda like a squeal. I've taken it back to the shop an after 2 hours of driving there, we plugged it in an left it and it didnt make the noise at all, so they were not interested in fixing it.
I've tried different leads, different guitars, plugged it in different rooms, have turned it on with nothing plugged into it an it still does it, even with the volume down.
Wanna get it fixed or find out what it is an sell it

Anyone have any ideas. Really wanna get to the bottom of this, might need to make another 2 hour trip to the shop an make them fix it or get it looked at, still have 4 an a half years of warranty on it!

 

[jtc_hunter]

Sounds like a faulty resistor or transistor somewhere. How long have you had it? If the store you bought it at thinks its ok, maybe you can return it and get something else?

 

[WashburnBass]

had it for maybe 4 months. its done this ever since i got it home, its the second amp i've had from that place, the first one blew in half an hour, and they wouldnt give refund, so i had to spend more to get this one, and after a 2 hour driving bring it back home, plugged it in as soon as i got home. i think i can safely say after i solve the problem on this one i wont be going back there in a hurry to buy stuff.