AD30tc troubleshooting; please help!

[peter]

Hi. I have been having a really frustrating problem with my first tube amp, an ad30tc, and no one I know seems to be able to help me (including the dealer and his 'technician'), and so Im hoping some amp guru/orange fanatic out there might be willing to help me out, as I know nothing.

the problem as I experience it is thus:

a) the larger tube, labelled 'PM GZ34', that sits to the left of the row of 4 smaller tubes when viewed from the back pannel, rattles like burnt out light bulb. That is, when I play at a sufficient volume, or when I take it out and shake it, it makes a little tinlking sound like a filament in dead light bulb. This in itself is rather annoying, but I was prepared to overlook it until...

b) after a while of this tube thing going on, my amp started to cut out at high volumes (let's say 3/4 gain and volume) after prolonged play. The cutting out occurs like a loud scratching sound, often in consecutive bursts, and it really really sux. Basically, I cant jam with a drummer for more that 1/2 hour before my amp starts to sound like a scratchy old record.

At first I tried changing channels, patch cords, and guitars, fiddling with the connecting wires between the speakers, and resecuring the tubes, but all to no avail. Then I took it to my dealer, who sent it off to some sketchy guy with a stutter who answered yes to all my questions (e.g., is it a tube problem?, didja fix the tubes?), but when I got my baby back a 2 weeks later the exact same thing was wrong with it. Aaaggggggh!! (lesson learned: people paid on commision dont care much to help you once they have your money)

Anyway, so I have this debilitating problem with my ad30tc, and I know nothing about amps. I dont which tubes do what, or what they're called, or even if the problem with my 'big tube' is at all related to the subsequent problem of the sound cutting out. If anyone out there would be patient enough to explain to me what I might do to try to fix my amp I would be eternally grateful, because at this point I'm about to cry.
thanks, Peter

[Meole]

The rectifier tube converts the AC power from an outlet into DC power your amp needs to run.
If the rectifier tube isn't working properly your amp could be getting the wrong voltages!
This can lead to further problems to your tubes and output transformer.

[peter]

Ummmmm, Which one is the rectifier tube? the big one?

[Meole]

The GZ34 is the rectifier tube.

[peter]

thanks.