2
3
Front panel*
*NOTE:
The JCM-1H front panel is illustrated. The
JCM-1C panel is identical but runs in the opposite
direction.
IMPORTANT:
Read before powering-up
Before powering-up your Marshall JCM-1
amplifi er, you must ensure that an appropriate
speaker cabinet is connected to the
corresponding impedance matched loudspeaker
jack on the rear panel, (unless ‘low power’ mode
is selected). Failure to do so could result in
serious damage being caused to your amplifi er.
Always use an unshielded loudspeaker cable to
connect an amplifi er to a loudspeaker cabinet,
never use a screened (shielded) guitar cable.
After use, always allow the amp to cool down
before moving.
IMPORTANT NOTE:
Please refer to the Warning
plate on either the underside, or the rear of the
product
1. Illuminated Power Switch
This is the On/Off switch for the mains electricity
supply to the amplifi er which will light up
whenever the amp is plugged into the mains and
the Power Switch is on.
NOTE:
Please allow a minute or so for the amp
to ‘warm-up’ after switching on. This is normal
with valve amplifi ers as valves need to reach their
‘working temperature’ to operate properly.
2. Bass
This control adjusts the amount of low frequencies
(bottom-end) in your sound. Higher settings
increase the ‘fullness’ of your tone, while lower
settings make the sound clearer and more
distinct.
3. Middle
This controls the mid-range of your sound.
Turning this up will make your guitar sound fatter
and fuller. Turning this down will make the sound
more ‘scooped’.
4. Treble
This control determines the amount of high
frequency (top-end) that is present. Higher
settings increase the ‘brightness’ of your tone,
while lower settings make the sound softer and
less defi ned.
NOTE:
The Treble, Middle and Bass controls
are highly interactive; adjusting one of them will
change the frequencies and range of the other
controls.
5. Boost Button
Pressing this button changes the pre-amp from
the classic ‘Master Volume’ voicing to the later
‘Split Channel’ boost sound. When active, the
sound is smoother and more distorted. With
the button out, the sound is more dynamic and
responsive to the guitar’s volume control. The
effect of this control is more apparent when the
Master Volume is at lower levels (less than 2
o’clock on the dial).
6. Master Volume
This control sets the overall output volume of the
amplifi er; it also lets you balance pre-amp and
power amp overdrive and so is often adjusted at
the same time as the Pre-Amp Volume control
(7). As the level is increased, the volume of the
amplifi er rises until the power amplifi er starts to
overdrive at which point the sound will thicken up.
7. Pre-Amp Volume
Adjusting this control changes the amount of gain
in the pre-amp. Low settings will give a clean
pre-amp and it will act as a volume control. Higher
settings will cause the pre-amp to overdrive.
Front panel
continued
*NOTE:
The JCM-1H rear panel is illustrated. The
JCM-1C panel is identical but runs in the opposite
direction.
WARNING:
Although your JCM-1 amplifi er has
2 extension speaker outputs, never attempt to
connect cabinets to both extension speaker
outputs simultaneously. Only use one speaker
output at a time.
1. Extension Speaker 8
Ω
This is the output that connects to an 8
Ω
extension
cabinet.
2. Extension Speaker 16
Ω
This is the output that connects to a 16
Ω
extension
cabinet.
3. Low Power switch
This switch activates the Low Power mode. The
amplifi er is connected to an internal dummy load
and a reduced level is fed to either internal speaker
(JCM-1C combo) or external load (both head and
combo). This level has been selected for personal
practice and is approximately 0.1-Watts.
NOTE:
With this button pressed, the amplifi er may
be operated without a speaker connected without
causing any damage.
4. Mains Input
Your amplifi er is provided with a detachable mains
(power) lead, which is connected here. The specifi c
mains input voltage rating that your amplifi er has
been built for is indicated on the back panel. Before
connecting for the fi rst time, please ensure that
your amplifi er is compatible with your electricity
supply. If you have any doubt, please ask the
advice of a qualifi ed technician. Your Marshall
dealer will help you in this respect.
The correct value of mains fuse located in the
small drawer at the bottom of the mains socket is
specifi ed on the rear panel of the amplifi er. The
drawer contains a space for a spare fuse.
NEVER
attempt to bypass the fuse or fi t one of the
incorrect value!
NOTE:
It is wise to carry spare fuses at all times.
Rear panel*
8. Input Jack Socket
This is where you plug your guitar into the amp.
You must use a screened (shielded) guitar cable.
Never use an unscreened (unshielded) speaker
cable. The input to any guitar amplifi er is a very
sensitive part of the signal path and is very
sensitive to electrical interference, hence the need
for a screened guitar cable.
Your screened cable should be
of good quality. If you are in any
doubt regarding this, your Marshall dealer will be
more than happy to help and advise you.
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JCM-1H and JCM-1C Technical Specifi cations
JCM-1H
JCM-1C
Power (RMS)
1W
1W
Valves
1 x ECC82 + 2 x ECC83
1 x ECC82 + 2 x ECC83
Dimensions (mm) H , W, D
180 x 380 x 195
360 x 380 x 220
Weight (kgs)
5.2
9.4
