1958X Front Panel
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1. INDICATOR
This filament bulb indicator will light up when your
amplifier is switched on. It will not be lit when the
amplifier is switched off and/or is not receiving
mains power.
2. STANDBY SWITCH
The Standby Switch is used in conjunction with the
Power Switch (item 3) to 'warm up' the amplifier
before use and to prolong the life of the output
valves.
When powering up the amplifier always engage
the Power Switch first, leaving the Standby switch
on 'Standby'. This allows the application of the
voltage required to heat the valves to their correct
operating temperature – hence the switch's name.
After approximately two minutes the valves will have
reached the correct operating temperature and
the Standby Switch can be engaged. Upon doing
this the H.T. (High Tension) voltage required by the
two EL84 output valves to pass signal (and hence
produce sound) is applied.
In order to prolong valve life, the Standby Switch
alone should also be used to turn the amplifier 'on'
and 'off' during breaks in a performance. Also, upon
full power down, always disengage the Standby
Switch prior to the main Power Switch.
3. POWER SWITCH
This is the On/Off switch for mains power to the
amplifier.
Note: Please ensure the amplifier is switched off
and unplugged from the mains electricity supply
whenever it is moved.
CHANNEL 2 - THE TREMOLO CHANNEL
4. TREMOLO SPEED CONTROL
This controls the speed of tremolo oscillation
when this effect (which can be switched on/off via
the supplied footswitch) is being used. Oscillation
speed increases when the Speed control is
turned clockwise and decreases when it is turned
anticlockwise.
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5. TREMOLO INTENSITY CONTROL
This controls the intensity or depth of the tremolo
oscillation when the effect is being used. The effect
depth increases when the Intensity control is turned
clockwise and decreases when it is turned anti-
clockwise.
6. TONE CONTROL
This adjusts the tonal character of the Tremolo
Channel. Turning this control clockwise increases
the amount of high frequencies (treble) present in
the sound.
7. VOLUME CONTROL
This controls the volume of the Tremolo Channel.
Turning it clockwise increases the volume level of
the channel.
8. CHANNEL 2 INPUTS
These are the guitar inputs for the Tremolo Channel.
The top one is the 'high sensitivity' input for this
channel, the bottom one is the 'low sensitivity' input
which is 6dB lower (i.e. half) than the 'high sensitivity'
input and has a darker sound. Always use a high
quality screened guitar lead.
CHANNEL 1 - THE NON-TREMOLO CHANNEL
9. TONE CONTROL
This controls the tonal character of Channel 1.
Turning the tone control clockwise increases the
amount of high frequencies (treble) present in the
sound.
10. VOLUME CONTROL
This controls the volume of Channel 1. Turning it
clockwise increases the volume level of the channel.
11. CHANNEL 1 INPUTS
These are the guitar inputs for this Channel and both
are identical.
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1958X Rear Panel
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1. TREMOLO FOOTSWITCH JACK
This is where the supplied Tremolo on/off footswitch
is plugged in.
2. LOUDSPEAKER OUTPUTS
There are two parallel loudspeaker output jacks
provided for connection to the internal speaker and/
or an external load, i.e. speaker extension cabinet(s).
When connecting speaker(s) please always ensure
that the amplifier's output impedance is set correctly
(item 3).
WARNING! Never use the combo without a load
attached! Always use a non-screened Marshall
approved speaker lead when connecting an
extension cabinet to these units.
3. OUTPUT SELECTOR
Matches the amplifier's output to the load
impedance. With all-valve amplifiers it is imperative
that the amplifier is connected to a load whilst in
operation and that the impedance selected on the
amplifier matches the total impedance of the internal
speakers and/or extension speaker cabinets.
Important Note: Failure to do so will result in
damage to the amplifier. The two internal speakers
are 16 Ohms each. These are wired in parallel
giving an overall impedance of 8 Ohms, therefore
the output selector should be set to 8 Ohms. If a 16
Ohm extension speaker cabinet is used instead of
the internal speakers the output selector should be
set to 16 Ohms.
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Note: No additional extension speaker cabinet with
an impedance lower than 8 Ohms should be used in
conjunction with the internal loudspeakers. Failure to
comply with these points will result in damage to the
amplifier. Your amp should be completely powered
down before the selector is turned.
4. MAINS FUSE
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.
5. H.T. FUSE
The correct value of H.T. fuse is specified on the rear
panel of the amplifier. NEVER attempt to bypass the
fuse or fit one of the incorrect value.
6. MAINS INPUT
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 shown on the back panel. Before
connecting for the first time, please ensure that your
amplifier is compatible with your electricity supply.
If you have any doubt, please get advice from a
qualified technician. Your Marshall dealer will help
you in this respect.
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