Marshall JCM 900 SL-X

MARSHALL JCM 900 SL-X
50w - Head (2500)
1993

Produced during the 1990's, the JCM 900 Mark IV SL-X (Super Lead X-tended) amp was an evolutionary link in the Marshall Master Volume series.By adding an extra ECC 83 (12AX7A) valve, Marshall engineers created a gain-drenched front end that combined twin gain controls, from 0-10, and another that went all the way to 20! This was the amp that KISS used on their world tours during the period. Ace Frehley and Paul Stanley could afford any amplifier, but they found only one with the sound they needed to fill arenas with the power of their raw, blistering rock 'n roll: the SL-X!

Although voiced for metal and thrash, these amps are also sensitive and can be trimmed for tone. Back off on the gain and you can still have the blues. Combine the gains and you can rock all over the world. Crank it and you'll be thrashing all the way to the top!

This is the top that I chose when playing clubs (some small and some up to 600-seats) with "The Blame" and "Plunge". For larger clubs I used the amp in its 100-watt power mode. For smaller venues, I used the low power mode to play at reduced volume. Of course, the amps I used were always mic'ed through the PA system anyway, so I just needed enough stage volume to hear myself. Some clubs had high stages or funny acoustics that literally soaked up all the volume I could muster. That's why I'm glad I opted for the 100-watt model.

Features
Twin gain controls from 0 to 10 and 10 to 20.
Twin footswitchable master volumes (A) and (B) for rhythm to solo volume switching.
Equalization controls for Treble, Middle, Bass, and Presence.
Effects loop with sensitivity control.
Direct and recording compensated line outputs.
Impedance selection switching.
Twin loudspeaker outputs.
High/low power switching (pentode to triode).
Valve failure LED's.
Entirely wired and assembled by hand.
Made in England.

Model 2100
4 x 5881 output valves, 4 x ECC 83 preamp valves
100 watts RMS
Vented top
Dimensions: 750 (W) x 310 (H) x 220 (D) mm.
Weight: 18.4 kg.
Optional foot pedal: P801

Model 2500
2 x 5881 output valves, 4 x ECC 83 preamp valves
50 watt RMS
Dimensions: 750 (W) x 310 (H) x 220 (D) mm.
Weight: 17 kg.
Optional foot pedal: P801

Tone Settings

This information is from Marshall product support tech John Teto, and previously appeared in the Fall 1994 issue of dealer magazine Marshall Feedback. Here's the list:

- Zep Rock - Presence: 7; Bass: 7; Middle: 6; Treble: 5; Master: 3; Gain: 14; Pre-amp: 3
- Cream-y Blues - Presence: 6; Bass: 5; Middle: 7; Treble: 7; Master: 3; Gain: 18; Pre-amp: 4
- Hardcore - Presence: 8; Bass: 8; Middle: 2; Treble: 9; Master: 3; Gain: 18; Pre-amp: 7
- Death - Presence: 10; Bass: 10; Middle: 0; Treble: 10; Master: 3; Gain: 18; Pre-amp: 8
- Cleaner Than U Think - Presence: 6; Bass: 6; Middle: 6; Treble: 4; Master: 10; Gain: 11; Pre-amp: 2


Gallery

Video - You Tube