HI GAIN MASTER VOLUME SL-X
The latest innovation from our valve designers involves the use of an extra ECC83 pre-amp valve in the gain
stage of the Master Volume SL-X models.
This gives a gain soaked front end that is the most extreme yet produced by Marshall and is controlled by twin
gain controls, the first (item 2), from 0-10, the second (item 3), from 10-20! Combinations of these two
controls can take you from classic Marshall crunch in lower positions, to pure overdriven outrage on
maximum. It is well worth experimenting with these twin gains in conjunction with the tone network (items
6-9) to really get to know the full capability of your new SL-X head.
The twin Master Volumes (items 4 & 5) are another unique feature of the SL-X amp giving you two
footswitchable output volume levels, ideal for rhythm to solo switching.
Although a clean sound is available, this amp was designed for the uncompromising high gain player who
demands a no compromise sound.
HI GAIN DUAL REVERB
The Dual Reverb range was designed for versatility with two independently controlled footswitchable
channels, each voiced totally differently.
Channel A is voiced for brilliant clean tones with the gain control (item 2) on lower settings and crunch to
lower gain lead as you turn it up.
Channel B is boosted with enough gain (item 3), for fearsome lead tones, ranging from classic on lower
settings to contemporary screaming solos on maximum.
Channel master volumes (items 9 & 11) and individual channel reverb controls (items 8 & 10) give you
incredible control and all round versatility in either, head or combo form.
VALVE OUTPUT POWER
The JCM 900 range use high quality 5881 output valves (x2 in 50 Watt models, x4 in 100 Watt models) for
their unique distortion properties and fluid tone.
With most valve amplifiers, particularly Marshalls', the best sounds are achieved when the Master Volumes
are set high enough to be utilising the driving power of the output valves to the full.
This delicate working balance between the pre-amp and power amp levels can only be achieved by
experimentation.
You will find that all the JCM 900 models like to work hard and are designed to withstand prolonged use at
full power quite readily. The PB100 Power attenuator is ideal for this use (connects between amp and
cabinets) as it will allow you to run your amp at full power but keep the overall volume low.
The important thing to remember here is that it is the interaction between all the controls that plays a part in
achieving your sound.
HI GAIN MASTER VOLUME 900 SL-X
FRONT PANEL FUNCTIONS
Models 2100 & 2500
1. Input Jack
Connects the instrument to the amplifier. (A high quality screened lead must be used).
2. Pre-Amp Volume Control
Sets the initial gain level of the pre-amp section (0-10). Lower settings for clean sounds - higher settings for
crunch and overdrive.
3. Gain Sensitivity Control
Sets the secondary gain level of the pre-amp section (10-20).
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NOTE:
Combinations of the two gain controls (items 2 and 3) provide a wide range of clean, crunch and overdrive
possibilities. Experimentation will reveal the optimum settings for each.
4 & 5. Master Volume “A” Master Volume “B”
Twin footswitchable Master Volume Controls. Master “B” controls the overall volume exclusively when a
footswitch is not connected. The connection of footswitch P801 allows switching between Master “A” or “B”
giving independent volume levels for rhythm and solo playing.
6,7,8 & 9. Treble, Middle, Bass & Presence
Passive equalisation circuit. These controls are interactive to provide the maximum range of tonal variation.
10. Master Volume B “ON” LED Indicator
Indicates red when Master Volume “B” is selected.
11. Footswitch Jack Socket
Input for the connection of remote footswitch (model P801).
12. Standby Switch
Controls the H.T. supply to the amplifier valves. Allows the filaments to remain heated during breaks.
13. Power Switch
On/Off switch for total mains power to the amplifier.
HI GAIN DUAL REVERB
FRONT PANEL FUNCTIONS
Models 4100, 4101, 4102, 4500, 4501 & 4502
1. Input Jack
Connects the instrument to the amplifier. (A high quality screened lead must be used).
2. Channel “A” Pre-Amp Gain Control
Sets the gain level for channel “A”. Lower settings give clean sounds - higher settings for medium drive and
crunch rhythm.
3. Channel “B” Lead Gain Control
Sets the gain level for boosted Channel B. Lower settings give slight overdrive - higher settings for maximum
drive and sustain.
4,5,6 & 7. Treble, Middle, Bass & Presence
Passive rotary equalisation circuit. These interactive controls provide a wide range of tonal possibilities for
both channels.
8. Reverb Control Channel A
Controls the amount of reverb on Channel “A”.
9. Master Volume Channel A
Controls the overall volume level of Channel “A”.
10. Reverb Control Channel B
Controls the amount of reverb on Channel “B”.
11. Master Volume Channel B
Controls the overall volume level of Channel “B”.
12. Channel B ‘ON’ Push Switch/LED
Indicates red when Channel “B” is selected either manually or by remote footswitch (models P802).
13. Footswitch Jack Socket
Connects the remote dual footswitch (models P802) for reverb ON/OFF and Channel A/B switching.
14. Standby Switch
Allows the amplifier to remain at “standby” (i.e. the valve heaters remain on, ready for instant use, but
without the signal circuit being active).
15. Power Switch
On/Off switch for total mains power to the amplifier.
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