Damn man, get well soon. Weren't you just sick? I think I remember you were sick around the same time I was.
I don't want to fix/mod any amp I buy....within reason. Little minor things that don't hurt it's resale value or any easy fix to get it back to stock is not a big deal if the price is right. I don't wanna buy someone else's headache though, like it actually kind of turned out with my 2204. That amp is great now, and I never hated it before, but I knew something wasn't right. Thankfully I got it for a really nice price, I got it back to it's natural glory and I haven't sunk a crazy amount of money into it. An amp that's been hacked and drilled and has had major pieces of it swapped out, like the one I saw yesterday, is of no interest to me. They'd have to take a hit for me to buy that amp, and GC is not in the business of taking hits. If they're selling it for 999, I bet they paid 500 bucks for it. I'd never pay that much for that amp. I'm not an amp flipper for profit, I want to keep my amps forever, but I want to be able to get fair value if I do decide to resell one of my amps. The reasons I want an 800 are simple - I like them in their natural state and a nice one will fetch big bucks if I ever need to resell it. There are clean unmolested amps out there. They pop up here and there. It's just a matter of lining up price, timing, and availability. I'm in no hurry, I just always keep my feelers out there. The wife is on board because the 800 2203 is the last piece of my puzzle.
Building a kit isn't out of the question, but they have very spotty re-sellability, and I just want the real thing. I wouldn't buy someone else's project, so I don't expect anyone else would want to buy mine.
999 pounds is about 1600 US dollars, so that's not too bad for a full 800/800 halfstack - if it indeed matched. A matching head and cab is worth a little more than a head and any ol cab. It depends on the head though. Not all JCM 800s are created equal. There are 6 distinct varieties and eras of JCM 800s. It basically goes like this:
1981 - mid 1985 (I think it's mid 85 anyway) - 2203/2204. 100/50 watt respectively. These are the most desirable and if Marshall has a Mt Rushmore, these amps are on it. These amps are the shit. Original circuit design, vertical inputs. Full on massive balls out rock and roll tone with undeniable punch and clarity. These are functionally no different from the 70s JMP first version master volume amps. Same exact circuit, although some component brand changes make the 800s generally a little brighter. They're just cosmetically different. These naturally command big bucks.
1986 - 1989 - 2203/2204 horizontal inputs. These are less desirable as the pots and jacks are mounted directly to the PCB. The 100w version got reworked internally to require less power and a redesigned/fewer filter cap setup, I think they went from 6 to 3 in-series filter caps or something, and some people think it lost it's mojo. The 50w remained the same as far as I know besides the PCB mounted pots. Or maybe I got them flipped, I'm just going off memory. One of them had major circuit design changes. Still good amps, but not at the level of the early models, and not as expensive. Usually these horizontal input 800s can be found for about 15-20% less than the vertical input models.
And during this whole run there were the 2210/2205 (100 & 50 w) two channel 800s. These amps have their loyal fans, but they are the least desirable of the 800 line up. I have no interest in owning one and I don't know too much about them. It has a limited "normal" channel and a lead channel, with extra gain via diode clipping.....like having a built in tube screamer. The tone stacks are different, the gain staging is different, the phase inverter is different, it's just a weirdo. It also has reverb and I think an effects loop. It might be Marshall's first foray into effects loops and these amps were Marshall's gateway into the modern era. These amps are drastically different than the single channel 800s and they really don't have that classic 800 sound, though some people swear by them. I have recorded many tracks from a guy that uses a 2205 (the 50w) and it sounded okay, but nothing great. I've recorded tons of tracks with a 2204, and the 2204 kills a 2205 to death. It's not even remotely close. These amps can be had for way less than the original vertical input amps. It's not uncommon to see these things, either 50 or 100 watt, going for around $750. That's like 50% off of what a vertical input model can go for. You'll never find a vertical input 2203/2204 for $750 unless it's completely broken or been in a fire, put out with gallons of water, peed on, and maybe dropped off a boat into the ocean.
And lastly, the 2203 reissue. Marshall's modern re-do of one of their most famous models. Vertical inputs, gigantic transformers, the whole nine yards. This amp pisses me off because it's $2400 new, and it doesn't need to be. It's such a basic primitive amp that they already fucking know how to make, so why does it have to cost $2400? Pisses me right the fuck off. They sound great, pretty much exactly like the originals to my ears, and they also have an effects loop. I'd happily buy one of these off the used market, but not for no original model price.
So, that's about it for 800s as far as I know.