Currently i use a Marshall AVT150 combo amp and im looking to up my output by hooking it up to an extended cab. My problem is i have no idea what is compatible or if it has to be a Marshall cab or what size i can/should use. I've looked into a Marshall AVT112 extended cab but no one sells them and all sites list them as obsolete. I've also looked into a Marshall 1912 but with little luck. Can someone recommend me something?
You dont get more volume from adding speakers, better sound dispersion and bass response maybe. But the AVT is far from worth getting a decent cab.

Dont polish a turd, put the money your saving along with selling your amp and get something that sounds how you want it to in the first place.

But if you're going to anyway look into Avatar, ENGL, Mesa if youre in the US, Matamp, Zilla and Orange if youre in the UK.

Marshall 1960As are cheap as chips on ebay though, and decent cabs.
Any cab will work. On a tube amp, you'd have to match impedance, but it doesn't really matter in this case.

Just make sure that it has enough wattage to handle you're output.

I can't remember if the avt cuts out the amps main speakers when an external is plugged in.

Just to be clear - this isn't going to give you any more ouput - with a 4x12 you might get a better projecting sound with more low end response, but you're amps output is limited to its wattage and speaker efficiency, not the number of speakers running.
Thanks guys, but by the sound of it, it seems like im going to need a new amp. as odd as it is i love my AVT because of all its effects and its distortion, if not a cab then what would one recommend as far as a half-stack goes?
I've had an old VS 8100 (which are better than the new AVT's) in my jam room running through an awesome Soldano 2x12. It still sounded like a steaming pile of smeg.
Nothing will fix an AVT apart from a garbage truck.
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