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MGP-1A Advanced Modeling Guide
Marshall
Marshall
®
Crunch
UK800
Mod
Deep
Bright
EQ
Shift
Alt
EQ(-)
Citrus
Cali
Crunch
Mid
Bass
Treble
Volume
JCM900
JCM900 ( Model 2100)
Marshall’s model diversity really exploded during the JCM800/900 era, with a heavy reliance on solid
state and opamp circuitry. Early JCM900 4100 amps were heavily based on opamps, but the JCM900
2100 was more along the lines of the JCM800 2205. This amp still has much of that Marshall character,
but is a voiced with deeper mids.
Power
Tubes
: EL34, Push Pull
Speaker
Cabinet
: 4 x 12” Celestion G12T-75 (1960x) or V30 (1960Vx)
JCM900 SL-X (2100SLX)
The JCM900 SL-X had two gain controls (Preamp Volume and Sensitivity). This allows the SL-X the
ability to reproduce clean, overdrive or heavy distortion tones all from a single channel. This MGP-1A
model is primarily concerned with emulating the SL-X’s heavier tones; Try the UK800 model for crunch
and clean tones.
The SL-X is capable of a spectrum of heavier tones, depending on the settings of the two controls. The
MGP-1A only has one Drive control, however, it is possible to accurately simulate this behavior. Here’s
how.
To simulate the sound where the Preamp Volume is turned up beyond 8 or so, turn the MGP-1A’s Bright
off and use the Drive knob as you would the Sensitivity knob.
To simulate the Sensitivity control turned up beyond 8 (18) or so, turn Bright on and use the Drive knob as
you would the Preamp Volume.
Intermediate settings are a bit trickier and will require some help from the EQ.
Power
Tubes
: 5881 or EL34, Push Pull
Speaker
Cabinet
: 4 x 12” Celestion V30 or Celestion G12T-75
Drive
Drive
Mid
Bass
Treble
Volume
Mod
Euro
Recto
Hot
Rod
Deep
Bright
EQ
Shift
Alt
EQ