Marshall Amplification 1992LEM - Manual (Page 4)

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1. POWER SWITCH
This is the On/Off switch for mains power to the amplifier. It will light up
when your amplifier is receiving the correct mains power and is switched
on. It will not be lit when the amplifier is switched off and/or is not
receiving mains power.
Note: Please ensure the amplifier is switched off and unplugged from
the mains electricity supply whenever it is moved.
2. STANDBY SWITCH
The Standby Switch is used in conjunction with the Power Switch (item 1)
to ʻwarm upʼ 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 ʻStandbyʼ. This allows the application
of the voltage required to heat the valves to their correct operating
temperature. After approximately two minutes the valves will have
reached the correct operating temperature and the Standby Switch can
be engaged. 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, when switching off, always disengage the Standby
Switch prior to the main Power Switch.
3. PRESENCE CONTROL
This control operates in the 1992LEMʼs power section and adds high
frequencies to your sound by altering the power amplifierʼs negative
feedback. Turning this control clockwise adds more edge and ʻsparkleʼ to
your sound, making it crisper and more cutting.
4. BASS CONTROL
This adjusts the bottom end, turning it clockwise increases the amount of
low frequencies in the sound.
5. MIDDLE CONTROL
This adjusts the level of those all-important mid-range frequencies.
Turning it clockwise increases the mids and fattens your sound, giving it
more punch. Turning it anticlockwise reduces the mids.
6. TREBLE CONTROL
This adjusts the top-end. Turning it clockwise increases the amount of
high frequencies (treble) present in the sound, making your tone brighter.
Note: The following four controls - PRESENCE (item 3), BASS (item 4),
MIDDLE (item 5) & TREBLE (item 6) - are all shared, meaning that they
all work on both Channel I and Channel II. The Treble, Middle and Bass
controls are highly interactive and altering one control can change the
way the other two behave. For this reason, experimentation is
recommended.
Lemmyʼs preferred settings are shown on the panel above.
7. VOLUME I
This controls the overall output level of Channel I, turning it clockwise
increases the volume. This channel is voiced for a higher treble response
than Channel II.
8. VOLUME II
This controls the overall output level of Channel II, turning it clockwise
increases the volume level. This channel is voiced for a ʻnormalʼ, flatter
response.
NOTE: When connecting to any input socket always use a high quality
screened guitar lead.
9. HIGH SENSITIVITY INPUT FOR CHANNEL I
This is the ʻhigh sensitivityʼ guitar input for Channel I - the brighter of the
two channels - and is the one Lemmy uses.
10. LOW SENSITIVITY INPUT FOR CHANNEL I
This is the ʻlow sensitivityʼ guitar input for Channel I. It is 6dB lower in
volume than the ʻhigh sensitivityʼ input and has a darker sound as well
due to its significantly lower input impedance.
11. HIGH SENSITIVITY INPUT FOR CHANNEL II
This is the ʻhigh sensitivityʼ guitar input for Channel II, the so-called
ʻNormalʼ channel.
12. LOW SENSITIVITY INPUT FOR CHANNEL I
This is the ʻlow sensitivityʼ guitar input for Channel II. It is 6dB lower in
volume than the ʻhigh sensitivityʼ input and has a darker sound as well
due to its significantly lower input impedance.
Performance Note: Bridging or ‘jumping’ the two channels
Because both Channels of the 1992LEM have the same number of gain
stages (two) and are therefore in phase with each other, it is possible to
bridge them together (ʻjumpingʼ or ʻlinkingʼ) and use them both at the
same time. Doing this enables you to expand upon the amps tonal
possibilities by mixing the two channels together. The same principal can
also be used to ʻdaisy-chainʼ two or more amplifiers together.
The most common way to utilise both channels is to plug your guitar into
the top (high sensitivity) input of Channel I and then run a short ʻjumperʼ
guitar cable (i.e. a screened cable) from the Channel Iʼs bottom (low
sensitivity) input to the top (high sensitivity) input of Channel II. (fig. 1)
The ʻreverseʼ is also possible – namely plugging your guitar into Channel
IIʼs top input and then running the ʻjumperʼ cable from Channel IIʼs bottom
input to Channel Iʼs top input. This less common approach can yield
some interesting tonal variations. (fig. 2)
1. LOUDSPEAKER OUTPUTS
WARNING!
Never use the amplifier without a load attached!
There are two parallel loudspeaker output jacks provided for connection
to speaker extension cabinet(s). Please always ensure that the amplifier's
output impedance selector is set correctly (see item 2) and ALWAYS
ensure you use good quality speaker (unshielded) cables. NEVER use
guitar (shielded) cables.
Always use a non-screened Marshall approved speaker lead when
connecting an extension cabinet to these units.
2. OUTPUT IMPEDANCE SELECTOR
Matches the amplifierʼs output to the load (speaker) impedance.
Your 1992LEM should be completely powered down before the Output
Impedance Selector is turned.
As is the case with any Marshall all-valve amplifier it is imperative that: a)
the amplifier is connected to a load whilst in operation and b) the
impedance selected on the amplifier matches the total impedance of the
extension speaker cabinet(s) being used.
1x16 Ohm cabinet - Selector on 16 Ohm - Use either speaker output
2x16 Ohm cabinets - Selector on 8 Ohm - Use both outputs
1x8 Ohm cabinet - Selector on 8 Ohm - Use either output
2x8 Ohm cabinets - Selector on 4 Ohm - Use both outputs
1x4 Ohm cabinet - Selector on 4 Ohm - Use either output
WARNING! Do NOT use any other combination of cabinets and/or
impedances. Doing so may result in damage to the amplifier!
An extension speaker cabinet with an impedance of less than 4 Ohms, or
two extension cabinets of 4 Ohms or less should NOT be used with this
amplifier.
Failure to comply with any of the points raised in this section will result in
damage to the amplifier.
3. MAINS SELECTOR
Matches the amplifierʼs mains transformer to the incoming mains voltage.
Your 1992LEM should always be completely powered down before the
mains selector is turned.
WARNING! ALWAYS ensure that this rotary selector is set to the correct
mains voltage applicable for the country where the 1992LEM is being
used. If you do not know, consult your authorized Marshall dealer.
Adjusting the selector from 230V to 120/100V or vice-versa will require
the mains fuse (item 5) to be changed to the correct value as detailed on
the rear panel.
4. 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 indicated 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.
5. 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.
6. H.T. FUSE
The correct value of this 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.
Technical Specification
Power Output - 100W RMS
Weight - 21.4 kg
Size - 740mm x 270mm x 210mm
* EUROPE ONLY - Note: This equipment has been tested and found to comply
with the requirements of the EMC Directive (Environments E1, E2 and E3 EN 55103-1/2) and
the Low Voltage Directive in the E.U.
* EUROPE ONLY - Note: The Peak Inrush current for the 1992LEM is 38 amps.
Front panel features
Front panel - Lemmy’s preferred settings shown
Rear panel
Rear panel features
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