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Marshall JCM800 2204 vs Marshall Silver Jubilee 2555
Circuit differences, stage by stage, from Gridleak’s verified redraws of both schematics: 30 differences, 19 the same.
What’s different, and why it matters
Both are EL34 heads with a long-tail-pair phase inverter and a solid-state rectifier, but the circuits differ widely. The Silver Jubilee doubles the output tubes to four, switches channels on a relay, adds diode clipping and an effects loop, and swaps the 2204's cathode-follower-driven tone stack for a different stack driven straight from a plate.
- The JCM800 2204 runs two EL34s and the Silver Jubilee 2555 runs four EL34s. With four output tubes to two, the Silver Jubilee 2555 makes more power (the JCM800 2204 is rated 50 W, the Silver Jubilee 2555 100 W), so it stays clean to a higher volume than the JCM800 2204.
- The JCM800 2204 has a cold-biased stage (10 kΩ cathode resistor, unbypassed) — it clips one half of the waveform early, which adds the harmonic grind of a hot-rodded preamp.
- The JCM800 2204 has a cathode follower and the Silver Jubilee 2555 doesn't. A cathode follower drives what follows it from a low impedance, so less is lost in the tone stack, and it compresses when pushed.
- Tone controls: treble / bass / middle stack with a slope resistor on the JCM800 2204, treble / middle / bass, other topology on the Silver Jubilee 2555.
- Features one has and the other doesn't: an effects loop (Silver Jubilee 2555 only), diode clipping in the preamp (Silver Jubilee 2555 only).
What they share: a long-tail pair phase inverter and a solid-state rectifier.
At a glance
| Marshall JCM800 2204 | Marshall Silver Jubilee 2555 |
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| Years | 1981–1990 | — |
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| Origin | UK | UK |
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| Rated power | 50 W | 100 W |
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| Channels | 1 | 2 |
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| Preamp tubes | 3 × 12AX7 | 3 × ECC83 |
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| Power tubes | 2 × EL34 | 4 × EL34 |
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| Rectifier | Solid-state (silicon diodes) | Solid-state (silicon diodes) |
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| Phase inverter | Long-tail pair | Long-tail pair |
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| Master volume | Master volume | Lead master / Output master |
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| Effects loop | no | yes |
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| Reverb | no | no |
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| Notable players | — | Slash, John Frusciante |
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Stage by stage
Inputs and channels
| Marshall JCM800 2204 | Marshall Silver Jubilee 2555 |
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| Inputs | 2 | 1 |
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| Channel switching | front panel only / none | footswitchable (relays) |
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| Voicing / power switches | none | Rhythm clip, Boost (pull), Power: High / Low |
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Preamp
| Marshall JCM800 2204 | Marshall Silver Jubilee 2555 |
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| Preamp tubes | 3 × 12AX7 | 3 × ECC83 |
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| Triode gain stages (all channels) | 3 | 4 |
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| Most gain stages in series | 3 | 4 (incl. 1 effects-return stage) |
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| Gain stage 1 | 12AX7 · plate 100 kΩ · cathode 2.7 kΩ, 0.68 µF bypass | ECC83 · plate 100 kΩ · cathode 2.7 kΩ, 0.68 µF bypass |
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| Gain stage 2 | 12AX7 · plate 100 kΩ · cathode 10 kΩ, unbypassed | ECC83 · plate 100 kΩ · cathode 1.5 kΩ, 10 µF bypass |
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| Gain stage 3 | 12AX7 · plate 100 kΩ · cathode 820 Ω, unbypassed | ECC83 · plate 100 kΩ · cathode 1.5 kΩ, unbypassed |
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| Gain stage 4 | — | ECC83 · plate 220 kΩ · cathode 470 Ω, unbypassed |
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| Cold-biased stage (clipper) | 10 kΩ | none |
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| Cathode follower | yes | no |
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| Bright cap(s) | 0.001 µF | 0.001 µF |
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| Coupling caps (preamp) | 0.022 µF | 0.022 µF / 0.047 µF / 0.1 µF |
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| Diode clipping | no | yes (5 diodes) |
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Tone stack
| Marshall JCM800 2204 | Marshall Silver Jubilee 2555 |
|---|
| Type | Treble / bass / middle stack with a slope resistor | Treble / middle / bass, other topology |
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| Position | after gain stage 3, driven by a cathode follower; no gain stages after it | after gain stage 4, driven by a plate; no gain stages after it |
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| Slope resistor | 33 kΩ | not on the drawing |
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| Treble cap | 470 pF | 220 pF |
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| Bass cap | 0.022 µF | not on the drawing |
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| Middle cap | 0.022 µF | 0.01 µF |
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| Pots | treble 250 kΩ · bass 1 MΩ · middle 25 kΩ | treble 220 kΩ · bass 1 MΩ · middle 100 kΩ |
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| Master volume | Master volume | Lead master / Output master |
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Effects
| Marshall JCM800 2204 | Marshall Silver Jubilee 2555 |
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| Effects loop | no | yes |
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| Reverb | no | no |
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| Tremolo / vibrato | no | no |
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Phase inverter
| Marshall JCM800 2204 | Marshall Silver Jubilee 2555 |
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| Type | Long-tail pair | Long-tail pair |
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| Tube | 12AX7 | ECC83 |
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| Plate loads | 82 kΩ / 100 kΩ | 82 kΩ / 100 kΩ |
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| Tail / cathode load | 10 kΩ | 10 kΩ |
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| Cathode bias resistor | 470 Ω | 470 Ω |
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| Input coupling cap | 0.022 µF | 0.022 µF |
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| Coupling to power tubes | 0.022 µF | 0.022 µF |
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Feedback
| Marshall JCM800 2204 | Marshall Silver Jubilee 2555 |
|---|
| Negative feedback | yes | yes |
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| Feedback resistor | 100 kΩ | 100 kΩ |
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| Feedback taken from | speaker output | 4 Ω tap |
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| Presence | yes (25 kΩ pot, 0.1 µF cap) | yes (22 kΩ pot, 0.1 µF cap) |
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| Resonance / depth | no | no |
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Power amp
| Marshall JCM800 2204 | Marshall Silver Jubilee 2555 |
|---|
| Power tubes | 2 × EL34 | 4 × EL34 |
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| Configuration | Push-pull | Push-pull, 2 tubes per side in parallel |
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| Bias | Fixed bias | Fixed bias |
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| Screen resistors | 1 kΩ | 1 kΩ |
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| Grid stoppers | 5.6 kΩ | 5.6 kΩ |
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Power supply
| Marshall JCM800 2204 | Marshall Silver Jubilee 2555 |
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| Rectifier | Solid-state (silicon diodes) | Solid-state (silicon diodes) |
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| First filter (reservoir) | 50 µF | 100 µF (2 × 50 µF) |
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| Filter nodes, in order | 50 µF → 50 µF → 50 µF → 50 µF → 50 µF | 100 µF (2 × 50 µF) → 50 µF → 50 µF → 50 µF → 50 µF |
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| Filter choke | yes (5 H) | yes |
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| Highest DC voltage printed on the drawing | 470 V | not printed |
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| Printed bias voltage | -57 V | not printed |
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