Amp head single-channel 100-watt lamp.
Lamps - 3 x 12AX7 preamp
- Power Tubes 4 x EL34

Setting: Presence, Bass, Middle, Treble, Master, Preamp

Input High or Low switchable not.

Attention, there are several JCM800 2203. Those of the early 80s are more famous than the late 80s (nearest JCM900)
Mine dates from 1982 (you can find out thanks to the serial number).

UTILIZATION

I always used the input High, the Low input is just feeble and takes very little part of the lamps ...
Configuration is very simple: EQ, Master, Gain ...

By plugging directly into the amp it gets immediately grain Marshall, not really way to go tap elsewhere.
BUT, you can tweak the lights to change the race preamp gain and / or add effects pedals the amp stand perfectly.
There are also plenty of mod to do or how to do ...

So the grain Marshall bidouillable what!

SOUNDS

First thing, beware the 100 Watts of 80 this is not the 2000s. The amp sounds good when the master is at least half = way too loud! Personally, I paid an attenuator otherwise the amp was not exploitable reasonable volume. (Apparently this is the same problem on version 50 Watts)

Second thing, the gain! Rather I want a good crunch boosted (or not) by the pedals rather than high gain vintage. I changed three 12AX7 for a 5751 combo, AX7 and AT7 in rectifier. The winning race became more progressive and I gained momentum. It truly was the revelation that change. Good afternoon if you are looking for high gain 3 AX7 do downright good!
My three essential pedals are: Boss GE-7 EQ + a + Fulltone OCD Xotic EP Booster ... It works great with the preamp tubes.

I often read that the head lacked bass equalization that was very effective: it's true ... But this is easily correctable with a EQ pedal. Frankly a beast GE-7 has brought a lot to my son!

I can not put away a year before managing to get sound I wanted so you still cling to, take an interest, do research, etc. ... Personally, I was pretty much on my purposes because I heard this sound mind in a lot of records (rock, punk, noise, post-rock).

I also use other effects: delays, reverb, tremolo ... it goes nickel in my JCM800!

My cabinet is a 1960A with Celestion G12-75. I think it works well (Marshall Marshall cabinet that still sounds good I feel).
I tried with a Mesa V-30, I shared mediums drool a little and pert mellow Marshall!
On a Hiwatt with HP Fane Vintage: outstanding! exellent sitting in the bass!
I'd tried the Greenback which apparently HP's preferred JCM800!

OVERALL OPINION

You want to make the hard rock? You arm your gibson ---> you play ---> you're happy!
This is the base register of the amp, the Marshall typical rock grain.
After customization are endless and this is what I love!

This is one of the most respected brand amp and it is justified!
If you like the marshall grain can not be loving.
If you want something else and like the hack, which is a geek effects pedals, it will do too!

I paid mine € 700 used in 2012 with lamps in good condition.
This is a good price I think. When I see some sell more than 1000 €, I find it a bit abused when even an amp past 30 years ...

I do not regret that choice.