Marshall Amplification JMP-1 Handbook

JMP-1

Valve Midi

Pre-amp

Handbook

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Marshall Amplification plc

Denbigh Road, Bletchley, Milton Keynes, MK1 1DQ, England

Tel: [phone]

Fax: [phone]

Web Site - http://www.marshallamps.com

Whilst the information contained herein is correct at the time of publication,

due to our policy of constant improvement and development, Marshall

Amplification plc reserve the right to alter specifications without prior notice.

Nov ‘98

Introduction

The relationship between the guitarist and amplifier has been our prime concern since the earliest
Marshall’s were produced. We always aim to give that extra edge, which can help to inspire the player,
fuelling creativity and the ability to express.

Advances in technology have allowed us to modify and enhance this basic principle for the benefit of the
musician. However, we have never lost sight of that extra emotional drive that only valves are capable of
producing. The whole character of our unique sound emanates from the breathing full bodied pure tone of
the valve.

Your JMP-1 MIDI pre-amp is a carefully designed coalescence between modern MIDI technology and
classic Marshall valve circuitry. It’s many tones are all valve generated and presented in a way that is both
comfortable and familiar to guitar players.

The digital control capabilities add a new degree of flexibility to the way in which the tones can be switched
and processed. The advantages provided by this level of control are truly astounding. After studying the
manual and with a little practical exploration, you will find an unbelievable range of sounds and will very soon
wonder how you managed without MIDI. The only limit is your own imagination.

JMP-1 Front Panel Features

1. Input Socket Connect the guitar to this socket.

2. Headphone Socket For the connection of stereo headphones.

Headphones with an impedance of 600 Ohms will give
the best performance. Connecting headphones does not
disable the outputs of the pre-amp.

3. Output Level Control Controls the volume level from the master left and right
outputs (Item 25).

4. Display The display is split into two sections and shows patch
and data information.

5. Patch Key Push this key to enter patch selection mode (0-99). The
patch key LED will illuminate to indicate patch mode.

6. Store Key Use this key to store a patch in the memory.

Operational Note:

Push once and the store key LED will flash. The data entry control (7) can now be used to change the storage location.
Pushing patch or a parameter key will abandon the store. Push the store key again to complete the store. (Also see
section Creating Your Sounds).

7. Data Entry Control This rotary control is used to increment/decrement data
information, or to select a patch in patch mode.

8. Volume Key Push this key to adjust the patch volume level between 0
and 20. The volume key LED will illuminate to indicate
that the volume parameter has been selected. The data
display will show the current value. The value can then
be adjusted using the rotary data entry control (7).

9. Gain Key Push this key to adjust the level of gain between 0 - 20.

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10-13. Tone Control Keys These keys should be combined to shape the Bass,

Middle, Treble, and Presence tone parameters. They can
all be adjusted between -6 and +6.

14. Effect Key This key varies the mix of the stereo effects loop between
0 and 12. At 0 only the direct signal is heard and at 12
only the effected signal is heard. When at 12 the loop is
effectively running in series i.e. no direct signal. This is
ideal for use with a graphic equalizer or compressor
limiter. As the effect parameter level is reduced, more
direct signal is introduced as with a parallel loop. This is
best suited to Chorus, Delay, Reverb etc.

15. OD1 Key This key selects overdrive 1, a warm vintage drive
reminiscent of Marshall Super Lead amps through to
modern day Master Volumes.

16. OD2 Key Selects overdrive 2. This a tightly focused high gain
drive which can be smooth or aggressive depending on
the E.Q. and gain settings.

17. Bass Shift This is a subtle low frequency character control which
can be switched in or out of any sound selection.

18. Clean 1 Key Selects Clean 1, which has a full warm character and
pure vintage tone.

19. Clean 2 Key Selects Clean 2. This has a bright sparkling tone ideal for
clean picking and ringing chords.

20. MIDI-Mapping Key The mapping function enables the mapping of incoming
MIDI patch messages to internal patches and outgoing
MIDI patch numbers to external devices. (See MIDI
mapping).

21. MIDI Channel Key This key selects the MIDI Channel on which the JMP-1
transmits and receives MIDI information.

22. Power Switch On/Off switch for mains power.

Rear Panel Features

23. Emulated Outputs Left and right outputs featuring Marshall speaker

emulation. The volume level from these outputs is
controlled by the volume level parameter key (8) not by
the output level control (3).

Operational Note: Stereo Speaker Emulation.

The Marshall speaker emulation circuit is a special filter which gives a signal virtually identical in sound to a speaker
cabinet. This allows you to link directly to the PA and obtain a stunning direct sound in a live situation. In the studio it
will give a true guitar tone direct to tape.

24. Emulated Level Selection Switch

Selection switch providing +4dB or -10dB output
levels on the speaker emulated outputs.

25. Master Outputs

Left and right outputs for connection to a power amplifier.

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26. Master Level Selection Switch Gives +4dB or -10dB Master output level options.

27. Effects Return Jacks Left and right jack sockets for connection from the outputs

of an external effects processor. If using a mono effects
processor the left hand return socket only should be used.
In this instance both the left and right master outputs and
speaker emulated outputs will now be working in mono.

28. Effects Level Selection Switch Provides level selection of +4dB or -10dB to match the
level of external effects processors.

29. Effects Send Jack Output for connection to the input of the external effects
processor.

30. Footswitch Socket Connection point for optional Marshall four way
footswitch to give 4 patch selection.

31. MIDI OUT Sends outgoing MIDI messages from the JMP-1.

32. MIDI THRU Sends out MIDI messages identical to those coming in

through the MIDI IN terminal.

33. MIDI IN Terminal to receive incoming MIDI messages from
external MIDI device.

When you switch on

When switching on the JMP-1, the unit will run through an initialising
process and will then default to the patch number that was selected when
the JMP-1 was last switched off (Fig1). Your JMP-1 is now ready for
action.

Creating Your Sounds

Your JMP-1 is capable of producing a vast array of different tones, stored in the 100 available patches.
The simplicity of creating and storing these sounds is a major advantage and feature of the pre-amp.
A “Patch” is a combination of all the programmable elements that you put in, therefore if all tone and
volume selections are at 0, no sound will be produced. Each patch is made up of:

(A) The channel selection i.e. OD1, OD2, Clean 1, Clean 2 & Bass Shift
(B) The individual volume, gain, tone and effects levels that you have selected.
The first step is to select a patch by pressing the patch key (5) using the rotary data control (7) to reach the

desired patch number. The next stage is to “build” your required sound, firstly by selecting the channel
OD1, OD2, Clean 1 or Clean 2 with or without bass shift, then by selecting the volume, gain, tone and
effects levels. These controls work in exactly the same way as a normal Marshall amplifier, where
increasing the gain brings in more overdrive and the tone selections interact to “shape” the sound.

The JMP-1’s controls are there to be used to the full and by experimenting with all the extremes you will
quickly understand it’s capabilities and build your own library of sounds.

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Patch Data

Patch

Store

Fig 1 Patch