Marshall Amplification JVM 2 - Manual (Page 4)

5 4
Channel Overview
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 hot-rodded JCM800 sound found
in ‘Crunch Red’, allowing you to dial-in two
distinctly different yet similar crunch sounds if
you so wish - one in each channel.
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.
The Basics
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.
E
N
G
L
I
S
H
E
N
G
L
I
S
H