Marshall Amplification 1959RR User Manual

Page 5

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.

2. OUTPUT IMPEDANCE SELECTOR

Matches the amplifier’s output to the load (speaker) impedance.
Your 1959RR 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 amplifier’s mains transformer to the

incoming mains voltage.
Your 1959RR 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 1959RR is being used. If you do not

know, consult your authorised Marshall dealer. Adjusting the selector from

230V/220V to 120V/110V/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 1959RR is 38 amps.

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 ‘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. 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.

Note:

The following four controls - PRESENCE (4), BASS (5), MIDDLE (6) &

TREBLE (7) - 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.

Randy’s preferred settings are shown on the panel above.

3. PRESENCE CONTROL

This control operates in the 1959RR’s power section and adds high frequencies to

your sound by altering the power amplifier’s negative feedback. Turning this

control clockwise adds more edge and ‘sparkle’ 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.

Tone/Tech talk - The modified Valve 1 stage

Unlike a standard Marshall 1959 Super Lead amplifier your Randy Rhoads

model contains a modification that increases gain and therefore extra distortion

within the circuit. This modification ‘hot rods’ the amplifier making it easier to push

it into the saturation levels necessary for the sound that Randy needed for his

musical station.

The change is very simple but effective and involves ‘cascading’ (feeding the

output of the first stage into the input of the second stage) the two halves of

valve 1. Traditionally, each half would serve as input buffer/first gain stage for the

two channels, i.e. one half for channel 1 and the other for channel 2, from there

they would separately feed the respective signals to the next stage which would

mix them, further amplify them and feed them to the tone stack.
Cascading valve 1 results in the guitar signal being increased by around 36dB or

60 times, much larger than it would normally be at this point in the circuit.

Subsequent stages then try to amplify this larger signal by similar amounts and

quickly run out of headroom causing the waveform to distort severely. The two

channel volumes still remain functional after the modification but adopt different

roles for their affect on the tone, allowing control of the extra gain and volume.

Plugging into channel 2 routes the guitar signal through the whole cascade circuit

while plugging into channel 1 allows you to bypass the cascade and use the amp

in its standard format where ‘Volume 1’ will function as it normally would.

Standard Channel 2 format is sacrificed due to the modification.

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. In full cascade mode,

this controls the amount of signal amplified by the second half of valve 1, thereby

acting as a crude master volume for the whole cascade circuit and can also be

thought of as a further gain control for the boosted signal to the subsequent

stages of the preamp. In standard mode i.e. guitar plugged into channel 1, it

functions just like a normal unmodified 1959 Super Lead volume control.

8. VOLUME II

Full cascade mode. This controls the amount of signal amplified by the first half of

valve 1 that is fed to the second half, thereby acting as a gain control for the

cascade circuit itself.

9. HIGH SENSITIVITY INPUT FOR CHANNEL I

This is the ‘high sensitivity’ guitar input for Channel I - the brighter of the two

channels - and is the most commonly used input on standard unmodified models.

Always use a high quality screened guitar lead. NOTE - Plugging into this input

bypasses the cascade and the amp functions in standard format.

10. LOW SENSITIVITY INPUT FOR CHANNEL I

This is the ‘low sensitivity’ guitar input for Channel I. It is 6dB lower (half) than the

‘high sensitivity’ input and results in less gain capability which may be required for

guitars with very hot output pickups or active circuitry onboard. NOTE - Plugging

into this input also bypasses the cascade and the amp functions in standard format.

11. HIGH SENSITIVITY INPUT FOR CHANNEL II

Plugging into this input enables the full cascade.

12. LOW SENSITIVITY INPUT FOR CHANNEL II

Plugging into this input enables the full cascade. It is 6dB lower (half) than the

‘high sensitivity’ input and results in less gain capability which may be required for

guitars with very hot output pickups or active circuitry onboard.

1959RR front panel features

Front panel

- Randy’s preferred settings shown

Rear panel

1959RR rear panel features

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