Marshall JCM800: every version
Every version, how to tell them apart, how to date one, and what to check before you buy. 5 versions, 1975–present.
The JCM800 is Marshall's 1980s valve range, and its core is the single-channel master-volume 2203 (100 W) and 2204 (50 W). That circuit started in 1975 as the JMP 2203 and 2204; in 1981 it was restyled as the JCM800 with the same insides, and from 1983 the split-channel 2205 and 2210 added a second channel, reverb and diode clipping. The 2203 has been reissued since 2002. The panel style, the model number and a few rear-panel changes place most of them quickly.
The versions, in order
JMP Master Volume 2203 / 2204 (1975–1981)
JMP
The first Marshall master-volume heads: one channel, a cascaded preamp and a master volume, in JMP cosmetics.
How to spot one
- JMP logo and a brushed-aluminium panel in the style of the 1970s Super Lead, with grille cloth on the head's front.
- Two inputs (high and low sensitivity) and controls for Presence, Bass, Middle, Treble, Master Volume and Pre-amp Volume.
- One channel with cascaded ECC83 gain stages ahead of a master volume.
- Model 2203 is the 100-watt head, 2204 the 50-watt head.
- Heads for the US market used 6550 output valves; others used EL34s.
Specs
| Rectifier | Solid-state (silicon diodes) |
|---|---|
| Phase inverter | Long-tail pair |
| Preamp tubes | 3 × ECC83 |
| Channels | 1 |
JCM800 2203 / 2204 and their combos (1981–1990)
JCM800
The same master-volume circuit in new JCM800 cosmetics, in heads and in 1×12 and 2×12 combos.
What changed from the JMP Master Volume 2203 / 2204
- 1981: new JCM800 cosmetics (full-width panel, larger logo, white piping, vinyl front) over the same circuit.
- 1984: a DI output was added and the input jacks moved from vertical to side by side.
How to spot one
- JCM800 cosmetics: a control panel running the full width of the chassis, a larger Marshall logo, white piping, and black vinyl in place of the grille cloth on the head's front.
- Inside, the early JCM800 2203 is the same circuit as the JMP 2203.
- From 1984 there's a DI output on the rear panel, and from late 1984 the two input jacks sit side by side instead of one above the other.
- Changes to the reservoir capacitors in the mid-1980s gave later amps a tighter response with less sag.
- The 4010 is the 1×12 combo and the 4104 the 2×12 combo version of the 50-watt circuit.
Specs
| Rectifier | Solid-state (silicon diodes) |
|---|---|
| Phase inverter | Long-tail pair |
| Preamp tubes | 3 × ECC83 |
| Channels | 1 |
JCM800 2205 / 2210 split channel (1983–1990)
JCM800
Two footswitchable channels, diode clipping on the lead channel, spring reverb and an effects loop.
What changed from the JCM800 2203 / 2204 and their combos
- A second, footswitchable channel, diode clipping for more gain on the lead channel, spring reverb and an effects loop.
How to spot one
- Two channels, switched from the front panel or a footswitch: a clean channel and a lead channel.
- The lead channel uses solid-state diode clipping for more gain than the single-channel 2203/2204.
- Spring reverb and an effects loop, neither of which the 2203/2204 has.
- Model 2205 is 50 watts and 2210 is 100 watts; the 4210, 4211 and 4212 are combo versions.
Specs
| Rectifier | Solid-state (silicon diodes) |
|---|---|
| Phase inverter | Long-tail pair |
| Channels | 2 |
JCM800 1959 and 1987 (no master volume) (1981–c. 1990)
JCM800
The four-input Super Lead and Lead 50 circuits carried on in JCM800 cosmetics, with no master volume.
How to spot one
- Four inputs (two channels) and no master volume, in the JCM800 panel and covering.
- Model 1959 is the 100-watt Super Lead; model 1987 is the 50-watt Lead.
- The same model numbers and non-master circuits as the 1970s JMP heads.
Specs
| Rectifier | Solid-state (silicon diodes) |
|---|---|
| Phase inverter | Long-tail pair |
2203X JCM800 reissue (2002 on)
Reissue
The 100-watt 2203 back in production after twelve years, with an effects loop added.
What changed from the JCM800 2203 / 2204 and their combos
- The 2002 reissue added a series effects loop and an impedance selector to the 2203.
How to spot one
- The JCM800 2203 layout and cosmetics, made in England.
- A series effects loop and an impedance selector on the rear panel.
- One channel with Gain, Bass, Middle, Treble, Master Volume and Presence into four EL34s.
Specs
| Power tubes | 4 × EL34 |
|---|---|
| Rectifier | Solid-state (silicon diodes) |
| Phase inverter | Long-tail pair |
| Rated power | 100 W |
| Preamp tubes | 3 × ECC83 |
JCM800 buying checklist
Date it
- Until 1983 the serial ends with a year letter; from 1984 the letter moves in front of the number (S = 1984, T = 1985, U = 1986, V = 1987, W = 1988, X = 1989, Y = 1990).
- Panel style: a JMP panel with grille cloth on the front means 1975–81; the full-width JCM800 panel and vinyl front means 1981–90.
- Two input jacks one above the other point to an amp from before late 1984; side-by-side jacks, to later.
- No DI output on the rear panel points to a JCM800 from before 1984.
Check it’s original
- A 2203 or 2204 is often modified for more gain (an extra gain stage or changed cathode parts); look for non-original components around the first preamp valves.
- US-market heads were built with 6550s; check whether an amp has been rebiased or converted to EL34s.
- Replaced filter capacitors are normal service work, not a sign of a fake.
- A JCM800-style head with an effects loop and impedance selector is a 2002-on reissue, not an original.
What usually needs work
- Old filter capacitors are due on most original JCM800s; dried caps add hum and stress the power section.
- Valve sockets and the cramped preamp board can develop crackles; check solder joints around the sockets and jacks.
- On 2205/2210 amps, the reverb and channel-switching circuits add more parts to check than on a 2203/2204.
Questions buyers ask
Is a JMP 2203 the same as a JCM800 2203?
Inside, the early JCM800 2203 is the same circuit as the 1975 JMP 2203; the JCM800 was a cosmetic change in 1981.
What's the difference between the 2203 and 2204?
Power: the 2203 is 100 watts with four output valves, the 2204 is 50 watts with two.
Which JCM800s have two channels?
The 2205 (50 W) and 2210 (100 W), introduced in 1983, and their combos. The 2203 and 2204 are single-channel.
Does the reissue sound like the original?
It follows the 2203 circuit and layout, and adds an effects loop and an impedance selector that the original doesn't have.
Amp vs amp
- Marshall 1959 Super Lead vs Marshall JCM800 2204
- Marshall JCM800 2204 vs Marshall Silver Jubilee 2555
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