According to Martin Gollub, who worked at LA sound design where Billie got his famous "Pete" amp modded, he had the amp modded to match the sound of Rob Cavallo's stock JCM 800 with vertical inputs that was used to record Dookie. Here are some more threads that talk about the 800s: http://www.marshallforum.com/threads/help-1973-jmp-sl-dookie-mod-1994-jcm900-slx.50344/, this one talks about the Dookie mod basically turning a plexi into a 2203 http://music-electronics-forum.com/t44025/,more
"I have almost exclusively used Marshall amps, but now I also use ENGL amps for stage work. I used Regular Vintage 50 and 100 Watt Marshall heads without a master volume until 1982, when the JCM 800 head was developed. I then used the JCM 800 with Rocktron pre amps as well. Currently I use one of three or four racks which include ENGL pre and power amps, Marshall 9100 poweramps and cabs with the addition ENGL backless cabs."more
"Right now I'm using a Marshall JCM-800. It's from the brief period when Marshall was switching production from the JCM-800 to the JCM-900, so although it's basically an 800, it's a two-channel amp, which they only made for a little while. I think the gain is a little bit darker sounding, a bit moodier than either the 900 or the 800."more
Marshalls. When I started, there was only fifty watts and a hundred watts. Now, when I have my choice, I get the JCM 800. Cabinets, to me, are not that big a deal because I don't have to have my cabinet match my heads. I prefer to have a full Marshall stack because it looks nice, but as long as I have a JCM 800 head, I can get whatever sound I want out of the cabinet.more
Jim Marshall claimed this was his favorite Marshall model of all time. To this day I cannot understand why.
I remember buying one of these used around '99. I was so excited. Wow what a let down. I really wanted a 2203 and didn't know it yet. This didn't last long. The clean channel is kinda weak until pushed into overdrive, then it gets some Plexi vibe (didn't know how to describe that at the age of 20 either). The 'overdrive' channel? Whoa what a mess. I know Tom Morello gets tones out of this model (or a similar model, he may have the 50 and 50s are typically sweeter in Marshall's line), but I never could. Shorty after I got my 1st and longest serving Plexi and then I got a 50 watt single-channel 800 combo and the scales lifted from my eyes. "Let there be tone," I said... and then I got that 62 candy panel AC30 and the Marshalls sounded a little less sweet. I found it harder to hear the luster, just the fury and the bluster....
but I digress... the channel switching 800s leave a lot to be desired, but if its between this and ANY JCM900, get the 800. You may be thinking that I got a bad unit or something, but I assure you that compared to some 's I've tried in stores since the turn of the century mine sounded downright good. None of them have any feel or touch responsiveness. I guess you don't need that with a footswitch to change sounds. The 80s and 90s were a strange time. We live in a comparative renaissance when it comes to tube tone and really all things guitar. Bask in it.
In closing, you could use one of these early channel switchers to amplify your guitar in blues, classic rock or even certain hard rock and metal situations. I don't recommend it, but you can try it. If you can't afford a serious 800 get yourself a Laney GH50L or 100L. The older the better. While they are almost a dead-rip-off of a single channel 800 with some 'modern' features I choose to ignore, the build quality wasn't a knock on a 2203 and it got worse every year.
It's a classic...nuff said. I only wish I got the 50 watt because I literally never use this thing anymore seeing as I never have the opportunity to crank it which is what it was built to do and it doesn't sound right at low volume.