Hey guys,

I have this problem with my practice amp that whenever I'be been playing for like 30-60mins the amp begins to make this very loud and unbearable white noise.

This noise lasts for as long as the volume knob is on and occurs even if theres no lead plugged into the amp.

can anyone help?
Tube amp? If it is, then I'd say you have a tube going bad.

If it's a SS amp, which I suspect it is, then it could be any number of things. Could be the volume potentiometer, or it could be a transistor. The bottom line is, if you're unfamiliar with electronics, you'll need to take it somewhere to have it fixed. Is it under warranty?
Unfortunately, it's a practice or "bedroom" amp, as we like to call them. At $120, it won't take long to reach half the value of the amp brand new. Labor, alone, will easily run $60 to $75 an hour. Start adding parts to the cost and you could easily hit $100, if not more.

If it was my amp, I'd take it apart and locate the problem. However, I'm also an electronics tech. Since it's a SS amp, it certainly can't hurt to pull it apart and have a look around. Problem is, even if you find something obvious, without a soldering iron and ability to solder, you're still dead in the water. It would almost be more cost effective to buy a newer, better amp.