Marshall Amplification JVM 2 manual Overview, Switch Store Mode, Preset Store Mode, III. Power Amp

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Overview

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I. Channels, Modes & Memory Presenting the 2-channel, 100W and 50W

all-valve JVM amplifiers. Their 2 channels boast 3 modes, giving you a total of 6 different modes to choose from - each with its own unique gain structure. Even though their front panel contains a total of 16 control knobs and 6 LED switches, the JVM is simple to understand and operate thanks to its extremely logical front and rear panel layouts.

The front panel contains dedicated sets of controls for each of their 2 channels - CLEAN / CRUNCH and OVERDRIVE - plus MASTER and REVERB sections. Each channel contains the familiar controls, Volume, Bass, Middle, Treble and Gain. The REVERB section consists of 2 Reverb level controls, one for each channel while the MASTER section is comprised of 2 footswitchable Master Volumes, plus master RESONANCE and PRESENCE controls that work universally on both channels.

Each of the 2 channels has 3 switchable modes. These are selected by the MODE switch dedicated to each channel. To select a channel press its respective MODE switch (or step on the relevant button on the supplied 4-way footswitch - see section II. Footswitch). To scroll through the selected channel's 3 modes keep pressing the said button and the colour of the LED in the switch will change from green to orange to red and then back to green. Doing this steps-up the gain level each time (red being the highest and green the lowest for each channel) and changes the channel's tonal voicing to suit.

When you leave and then reselect a channel, it will automatically recall the last active mode as both channels remember the last mode they were in until a change is made. For instance, if you select the Overdrive channel's orange mode and then go to the Clean channel, when you reselect the Overdrive channel it will still be orange.

In addition to channel and Mode selection, other features switchable via the front panel and the supplied 4-way footswitch are Reverb (on/off) Master Volume selection (1 or 2), and Series/Parallel effects loop (on/off). All 3 of these options are also remembered by each Mode.

To sum up, each of the JVMs 6 Modes will remember its most recent Reverb, FX loop and Master Volume selection. Additionally mode

setups can also be saved and recalled to one of 128 locations via MIDI.

II.Footswitch (UK patent pending) The JVM come supplied with a 4-way programmable footswitch which can be connected to the amp via any standard guitar cable.

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*Please note that the supplied Footswitch lead is unscreened and not suitable for guitar.

The 4-button footswitch features 5 LEDS marked CLEAN / CRUNCH, OD, MASTER, REVERB & FX. The LEDs for each of the 2 channels are 3-coloured Green, Orange and Red, visually telling you which channel and mode is selected alongside the status of Master, Reverb and FX loop.

The footswitch enables you to assign any of its 4 switches to instantly recall any front panel function (Switch Store Mode) or complete channel setup (Preset Store Mode) in any order and combination.

For example, you could program it so that:

Switch Store Mode

Any footswitch is assigned to act as any one of your amp’s front panel switches: Channel/Mode; Reverb on/off; Master Volume 1/2 and FX Loop on/off.

If a switch is assigned to select a particular channel once is has been activated, it can be used to scroll through the three modes, just like its respective front panel switch.

Or…

Preset Store Mode

Each switch can be programmed to instantly call up a combination of JVM button options to form a Preset.

For example, you could program a mixture of switching functions (in our example switches #1 and #2 work in Preset Store mode, and #3 plus #4 work in Switch Store mode), so that:

Footswitch #1 = Overdrive channel, green mode with Master Volume ‘1’, Reverb ‘on’ and FX loop ‘off’.

Footswitch #2 = Clean channel, red mode with Master Volume ‘2’, Reverb ‘off’ and FX loop on.

Footswitch #3 = FX loop on/off

Footswitch #4 = Master 1/2

All the settings are stored within your footswitch; this means it can be plugged into any JVM amplifier and all your footswitch settings can be instantly recalled.

Details on how to program your footswitch can be found later in this manual.

III. Power Amp

The power amp stage of the JVMs is based on the same as the one found in the JCM800 2203 and 1959 Superlead amplifiers and their 50W cousins, responsible for the legendary Marshall roar it has been adjusted to suit the variety of tones found in the JVM. This section features Presence and Resonance control to help shape the overall tone of your JVM amplifier.

Your JVM is also equipped with a Silent Recording mode. When the STANDBY switch is OFF the power amplifier section is disabled but the rest of the amplifier remains fully operational.

IV. Studio Quality Reverb

The Marshall JVM is equipped with a studio quality digital reverb routed in parallel to the main signal and mixed by means of a valve.

When the reverb is engaged no degradation of the direct signal occurs and when off it is effectively removed from the circuit. Each of the JVM’s channels also has its own dedicated Reverb level control.

The Reverb switching has been designed to avoid abrupt cut offs in the reverb tail so when changing from channel to channel or switching the reverb off, its tail naturally decays.

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Contents Page From Jim Marshall EnglishOverview Switch Store ModePreset Store Mode III. Power AmpMains Input & Fuse Basics Channel OverviewFX Loop Front Panel OperationMaster 1 / Master 2 PRESENCE, ResonanceEmulated Line OUT FootswitchRear Panel Operation Serial / Parallel FX LoopKeep These Instructions Technical Specification HeadsTechnical Specification Combos Follow all instructions and heed all warningsJVM210H / JVM205H front panel Gain Stages JVM 2 Channel Block Diagram