The Basics
Channel Overview
ENGLISH
We recommend that you fold out the inside back cover of this manual so that diagrams of the amp’s front and rear panels are visible while you read.
MAINS INPUT & FUSE (17)
Your amp is provided with a detachable mains (power) lead, which is connected here. The specific mains input voltage rating that your amplifier has been built for is indicated on the rear panel.
WARNING: Before going any further, make sure your amplifier is compatible with your electrical supply. If you have any doubt, please get help from a qualified technician - your Marshall dealer can help you in this respect.
The correct value of mains fuse is specified on the rear panel of the amplifier. NEVER attempt to bypass the fuse or fit one of the incorrect value.
Mains (POWER) Switch (1)
This is the On/Off switch for the mains electric power to the amplifier.
Note: Please ensure the amplifier is switched off and unplugged from the mains electricity supply whenever it is moved!
INPUT Jack Socket (10)
You must always use a screened (shielded) guitar cable and never use an unscreened (unshielded) speaker cable. Also, this cable should be one of good quality. If you are in any doubt regarding this, your Marshall dealer will be more than happy to help and advise you.
Getting Started & Powering Up
1.Make sure that the speakers/cabinet(s) are connected to the correct impedance LOUDSPEAKER jack(s) on the rear panel (11). See page 8 for specifics regarding impedance matching. If you’re using an extension cabinet make sure its rating is enough to handle the power of the amp and also that you’re using a proper speaker cable. Never use a screened (shielded) guitar cable for this purpose.
WARNING!
1.Failure to do any of the above will damage your amp.
2.NEVER use your amp without a (speaker) load attached when the Standby Switch is ON.
Marshall recommends you always leave a (speaker) load attached to the unit.
2.Ensure that both MASTER VOLUMES on the front panel (5) are set to zero.
3.Connect the Footswitch Cable to the Footswitch and then connect to the FOOTSWITCH Socket (15) on the rear panel of the amplifier.
4.Connect the supplied mains (power) lead into the MAINS INPUT (17) on the rear panel first and then into an electrical outlet.
5.Plug your guitar into the INPUT jack socket (10) on the front panel.
6.Turn the front panel POWER switch (1) on. This will glow red then wait for a couple of minutes.
7.After waiting a couple of minutes, engage the STANDBY switch (2). Leaving the amp on ‘Standby’ for a period allows the valves to come up to their correct operating temperature. In order to prolong valve life, the STANDBY switch should also be used to turn the amplifier on and off during breaks in a performance.
STANDBY Switch & Silent recording (2)
As stated above the STANDBY Switch is used in conjunction with the POWER Switch to ‘warm up’ the amplifier before use and to prolong the life of the output valves.
When the amplifier is in standby mode the whole preamplifier section continues running at its nominal voltages whilst the power amplifier remains in a standby status. This allows the amplifier to be used for silent recording or preamplification purposes.
NOTE: Only when the STANDBY is off can the amplifier be used without a load for silent recording. Always ensure a load is connected when leaving the silent recording mode, i.e. when switching the STANDBY switch ON.
The JVM’s front panel is divided into 2 main sections: Channels and Master. Each of its channels has 3 modes which are distinguished by a different coloured light (green, orange or red) appearing in the respective MODE switch; the preamplifier’s gain structure is uniquely reconfigured for each and every mode.
CLEAN/CRUNCH CHANNEL (8) CLEAN/CRUNCH GREEN MODE: This is the cleanest of the three modes and, in keeping with traditional clean amps, it uses a simple and straightforward circuit keeping the signal as pure as possible. In this Mode the channel’s Volume control is taken out of circuit as is the case in vintage amplifiers of this nature. This is the only JVM mode where this happens.
CLEAN/CRUNCH ORANGE MODE: This mode shares the preamp topology of the classic Marshall JTM45/1959 ‘Plexi’ models (i.e.: gain + gain + tone) but with a bit more gain than is found in the originals.
CLEAN/CRUNCH RED MODE: This mode is reminiscent of the Marshall JCM800 2203 amplifier, a staple of hard rock. The gain structure is gain + gain + gain + tone.
OVERDRIVE CHANNEL (9) OVERDRIVE GREEN MODE: This is very similar to the
OVERDRIVE ORANGE MODE: This adds another gain stage to the ‘Overdrive Green’ circuit, resulting in a sound that’s perfect for singing leads and hard rock/heavy metal tones.
OVERDRIVE RED MODE: Adds more gain to the ‘Overdrive Orange’ for a high gain Marshall sound.
ENGLISH
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