So lately my 5150 has been buzzing/scratching. I'm 100% positive it isnt the gain because when I turn down the volume on my guitar it is still there.
Any ideas?
Oh and to fix a scratchy knob you can just blast it with some compressed air correct?
I never thought about that, but about 6 months old.
It's been used mainly for practicing but probably gigging in the future
Well, start off with the easy stuff first. Cause Im sure it wouldnt be your tubes...

- Try a fresh guitar cable.
- Make sure your guitar doesnt have any loose solder points.
- Make sure theres no electronics on the same circuit as the amp (fridge, microwave, TV, stereo, lamp, heater, cell phone charger...etc.)
- Stand farther away from the amp.
- By-pass your pedals, plug straight into the amp. If the noise stops...its one of your pedals.
- Check your speaker cable

If none of this kind of stuff works...THEN take the amp apart and try cleaning the guts.

BUT NOT UNLESS YOU KNOW WHAT YOURE DOING 100%! You wouldnt want to get electrocuted or anything...which can be lethal in some cases.

Actually...if none of the stuff I listed off helps...take it to a pro. Itll cost only a little bit...but its worth it.
Another simple thing is to just take all the tubes out and put them back in different slots. That might do the trick.