Tech, did you buy the head from Mr Pablo?
If so, a few things to note, coz it was mine before that!
It's a Trace AH300-12, not the SMX preamp but the slightly revised GP12X preamp. (The only differences being the slightly revised front panel including EL panel and a revised compressor circuit).
I bought the amp 2nd hand from Andertons in 2000, it is a proper AH300 but the original EL panel broke and GM Audio only had panels for the combo left, so i took one of those to make it work The tube is a Sylvania which I put in there for more grit than the stock Sovtek (unless you or Rob changed it?).
Cracking amp, miss it muchly, and someone will get a bargain at that price