Amp losing power

holbach36 · #1 03-29-2011, 11:39 PM

I own a GP12 AH400SMX Trace Elliot. I bought it used with a Peavey 810 cab. At Volume 2 it would take down walls. It was too loud and too muddy so I changed the cab into a cheap GK goldline 410. I started out OK, I got a more clear sound and still very loud at 4.
Lately it seems that I need to increase the volume several times during practice and the sound is not as good anymore.
I think the head is going bad.
I am flat broke right now and it will be a while before I can send it to a tech, so I wanted to hear from more experienced players/ techs to see if I anybody has an idea of what could be going wrong with my rig.
thanks

Alex1984 · #2 03-30-2011, 02:55 AM

You might want to check the pre-amp tube first. It does sound like symptoms of a dying pre-amp tube. If this is the case, it'll be about $10 ~ $15 bucks to put another one in.

Good luck!

BTW, pre-amp tubes are fully user replaceable and shouldn't require any biasing of sorts, in case you were worried.

rhopper · #3 03-30-2011, 04:46 AM

I just went through the same type of problem this past weekend. I replaced the preamp tubes and it fixed the problem.

MuzikMan · #4 03-30-2011, 04:53 AM

Check your preamp tubes AND your batteries.

Bassmec · #5 03-30-2011, 05:02 AM

Quote:

Originally Posted by MuzikMan

Check your preamp tubes AND your batteries.

Then replace the power supply caps and have it biased.
Poor old thing! Mosfets need biasing too you know.