Well, my bugera 333 makes this really loud hissing noise on low volumes.
It's comming from the left front part of the amp.
If I hit that part of the head, the noise stops.
So is there a big problem or should I just keep on hitting the amp everytime it occurs?
There is probably a problem. Bugera are notorious for low quality control, so this might be the problem. You should probably get it checked out.
Have you read BeerChurch's blog? There's good info about Bugera in there.

This sounds like a loose grounding somewhere. If you're comfortable opening the amp up (it's possible to kill yourself) take a look around. It's probly the main chassis grounding, IIRC that's on the left side of the amp. You'll need to do your own QC with Bugeras

edit: in case you're not comfy with opening her up, take it to a tech or return it.
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If there is a problem, continuing to hit your amp is not going to solve anything.

My opinion is that if you have to start a thread asking us if hitting your amp is acceptable then I suggest you not try to fix anything yourself and take it to a tech.

Edit: Normally, I'm all for fixing things yourself, but that OP henis was
Last edited by 311ZOSOVHJH at Jan 2, 2010,
Does sound like a dodgey connection as stated above. There is one thing you can do yourself that may be worth a try. Buy some contact cleaner, turn off the amp, remove each tube one at a time, spray some contact cleaner on the pins and then slide the tubes in and out a few times to clean it, then move onto the next one and do the same.
If it's a dodgey earth strap or something this won't help but if it is just a dirty tube socket then it will. It isn't a bad thing to do anyway and is something worth doing every time you change your tubes too. Who knows how clean an environment Bugeras are assembled in huh? The factory monkey may have had soy sauce on his fingers.
If this has no affect, I'd have to agree with 311 and take it to a tech.
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