I found a 1981 Carvin x100 tube 2x12 combo for $250 usd and was wondering if this would be a good buy. The ad says that the amp is in good condition, but there's only one picture so I don't really know. I'm not really actively looking at amps, this one just happened to show up while I was looking at guitars lol, but if it's a good buy I'm willing to do it.
Will Lane thank you! I'm not sure, I haven't contacted the seller yet. I definitely will if I can. Do you have any advice on what to look and listen for? I'm sorta new to amps lol
crmsndragonwn1 General wear and tear on the tolex will tell you if it's had a life on the road or not. Obviously if it's been beaten up externally the chances are it's been beaten up internally as well.

Also for an 80s amp you should expect that it's possibly been into the shop once or twice in its lifetime. Most important thing you need to know from the seller is if any of its major components have been replaced, or if it's had any mods done to it. In either case I'd forget about it and keep searching for another one; best not to inherit someone else's problems.

Also if you get a chance to play it, listen for any crackling or weird noises. Also look for any strange red or blue glow to the tubes, or any white build up at the tops of the tubes (silvery grey build up is fine). Even better, if the seller will let you open the back of the amp up, or if the tubes are exposed, tap them lightly with a pencil and listen for any sound through the speakers. All of these things will give you an indication of whether a tube is fine or on its last legs.

The moral of this story is, most issues with vintage amps are usually solved pretty easily by a tube change and rebias. As long as it hasn't had any major surgery, you should be fine. In fact a lot of the time an old set of tubes is a good way to talk the seller down In price.

If in doubt though, just wait until another good deal comes up. Because I can tell you, if I'd impulse bought every amp I thought was a good deal, I'd have hundreds by now. Amps are big ticket items that cost a lot of money and take up a lot of space; so you'll always find people needing to move them on fast and cheap for one reason or another. So in saying that... the other moral of this story, is never pay full price, because a better deal is almost always just around the corner.
'66 Fender Bassman, '82 Marshall JCM800 4210, '86 Laney AOR 100, '90 Marshall JCM900 MKIII 2500, '97 Marshall JCM600, Silverface Mesa Dual Rectifier, Peavey 6505, Marshall JCM2000 DSL-100, VOX AC30CCH, Marshall JMP-1 + EL34 50/50