Bedienungsanleitung Marshall JTM45_100 (Seite 4 von 5) (Englisch)

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1. 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.

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 heater voltage to bring the

valves to their correct operating temperature. After

approximately two minutes the valves will have reached

their correct operating temperature and the Standby

Switch can be engaged,enabling the HT without

'shocking' cold valves.

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. INDICATOR

This 6.3 Volt incandescent filament indicator will light up

when your amplifier’s heaters are energised at mains

power switch on,(irrespective of standby switch

position).It will not be lit when the amplifier is switched

off and/or is not receiving mains power.

4. PRESENCE CONTROL

This control operates in the JTM45/100's power section

and adds high frequencies to your sound by altering the

power amplifier's negative feedback.Turning this control

clockwise adds more 'sparkle' to your sound,making it

crisper and more cutting.

5. BASS CONTROL

This adjusts the bottom end,turning it clockwise

increases the amount of low frequencies in the sound.

6. 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,producing a more

'scooped' tone.

7.TREBLE CONTROL

This adjusts the top-end.Turning it clockwise increases

the amount of high frequencies present in the sound,

giving your guitar tone a brighter edge.

Note: The following four controls - PRESENCE (item

4),BASS (item 5),MIDDLE (item 6) & TREBLE (item 7)

- are all shared,meaning that they are common to both

Channel I and Channel II.They are highly interactive and

altering one control can change the way the others

behave.For this reason,experimentation is

recommended.

8. LOUDNESS 1

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,

hence its 'High Treble' labelling.

9. LOUDNESS II

This controls the overall output level of Channel II,

turning it clockwise increases the volume level.This

channel is voiced for a 'normal',flatter response and is

labelled as the 'Normal' channel.

10. HIGH SENSITIVITY INPUT FOR

CHANNEL I

This is the 'high sensitivity' guitar input for Channel I,the

so called High Treble channel.It is the most commonly

used input.Always use a high quality screened guitar

lead.

11. LOW SENSITIVITY INPUT FOR

CHANNEL I

This is the 'low sensitivity' guitar input for Channel I.

12. HIGH SENSITIVITY INPUT FOR

CHANNEL II

This is the 'high sensitivity' guitar input for Channel II,

the so called 'Normal' channel.

13. LOW SENSITIVITY INPUT FOR

CHANNEL II

This is the 'lo

w sensitivity' guitar input f

or Channel II.

Interesting aside: Back in the day,a 'high sensitivity'

input jack was recommended for use with a guitar

loaded with low-output pickups (e.g.:single coils) while

Tone Circuit: In typical Marshall fashion,the JTM45/100’s shared tone network is passive and interactive.By

interactive we simply mean that the settings of the Bass and Treble controls affect the amount of mid-dip (cut)

available via the Middle control.

Tag Boards: The tag boards used in your hand wired re-issue are exactly the same as those in the original in terms

of thickness and matrix pitch.The material we're using is made exclusively for us and is ‘UL recognised Micom type

Marshall EM42’.The reason we didn’t use a board with the exact same chemical composition as in the original units is

because that material doesn't pass current safety requirements regarding flammability.

Transformers: The mains (power) and output transformers are vital to the performance,sound and feel of an all-

valve amplifier.Because of this we spent a great deal of time studying and analysing the constructional methods and

materials used in the original transformers so we could match everything as closely as possible.We also went to great

lengths to ensure that the all-important electrical characteristics and performance of the originals were duplicated

exactly.In order to achieve these vitally important goals we worked extremely closely with our associates in the R&D

department of Drake – the company which supplied us with the output transformers used in the original JTM45/100.

Mains (Power) Transformer: In the original JTM45/100 the mains transformer was an “off-the-shelf” device

purchased from a highly regarded general electronic components supplier.Referred to as the “RS De Luxe ”this

transformer is no longer available,but with the help of Drake’s expertise we were able to replicate the performance

of the original “De Luxe” of which we have several genuine examples.We paid particular attention to an important

electrical effect called ‘regulation’ which is the variation in behaviour of the HT voltage and current from the

transformer and is dependant on load demand (i.e.how loud you’re playing!).This behaviour affects how the amplifier

compresses and reacts to saturation when played at high volumes – hence its importance.

Output Transformers: As already mentioned,the pair of output transformers used in the original JTM45/100s were

supplied by Drake,as are those in your reissue.Fortunately Drake still had their original documentation intact after all

of these years,a factor which obviously helped ensure that the reissues are 100% accurate.

Power Supply: This circuit has the same exact filtering on the H.T.(high voltage DC,a.k.a.the B+ voltage) line as the

original versions,a factor that contributes to the JTM45/100 having a unique,dynamic characteristic all of its own.

Chassis: We are using a box-section chassis made from 16-gauge mild steel with butt-welded corner joints.The steel

is also passivated giving lifelong resistance to corrosion.

Front Panel: Extra thick,gold coloured Plexiglas (actually Perspex,causing some people to refer to it as ‘Perplexi’!),

exactly as the original.Specific details pertaining to the front panel features can be found on page 5 of this manual.

Rear Panel: Made from cream styrene with gold print,just like the original references.

Head Cabinet Construction: High-grade,flawless (knot-free) Baltic birch-ply with finger locked joints for maximum

strength.The main cabinet frame (sides,top and bottom) are 15mm ply,the front baffle is constructed from 12mm ply

while the back of the cabinet is 9mm ply.All edges have a 15mm radius.

Head Cabinet Cosmetics: The Marshall Block logo,black Levant covering,original venting,beading and piping

duplicate the look and style of the originals.

ENGLISH

Front panel features

1 2 3 4 5 6 7 8 9 11 13

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Marshall JTM45_100 Seite 4

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