Marshall Amplification JTM30 User manual

JTM Series
JTM30
Valve Combo
Handbook
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Marshall Amplification plc
Denbigh Road, Bletchley, Milton Keynes, MK1 1DQ, England
Tel: [phone]
Fax: [phone]
Web Site - http://www.marshallamps.com
Whilst the information contained herein is correct at the time of publication,
due to our policy of constant improvement and development, Marshall
Amplification plc reserve the right to alter specifications without prior notice.
Jan ‘99

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WARNING!
Please read the following list carefully.
A. ALWAYS fit a good quality mains plug conforming to the latest B.S.I.
standards where necessary (UK only).
B. ALWAYS wire the plug according to the colour code attached to the
mains lead.
C. NEVER under any circumstances operate the amplifier without an
earth.
D. NEVER attempt to by-pass the fuses or fit ones of the incorrect value.
E. NEVER attempt to replace fuses or valves with the amplifier connected
to the mains.
F. DO NOT attempt to remove the amplifier chassis, there are no user
serviceable parts.
G. ALWAYS have this equipment serviced or repaired by competent
qualified personnel.
H. NEVER use an amplifier in damp or wet conditions.
I. DO NOT switch the amplifier on without the loudspeaker connected
and ensure that any extension cabinets used are the correct impedance.
J. DO NOT obstruct airflow around amplifier.
K. PLEASE read this instruction manual carefully before switching on.
Introduction
Marshall Amplification has been inextricably linked with valve
amplification since our very beginning in 1962. Products such as the original
Bluesbreaker combos, JTM 45 and Super-Lead heads were all destined to
be, and have become, classics in their own right. All of these special
Marshalls produced their magical tone by driving the guitar through an all
valve pre-amp into a pure valve power-amp. The JTM 30 carries on this
grand tradition but meets the demands of contemporary guitarists by
providing features such as channel switching, reverb, effects loop and
Speaker Emulated output.
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Using the JTM 30
The JTM 30 is easily capable of
producing a wide range of useable
quality tones, from glassy vintage
clean, Bluesbreaker type singing
lead and crunchy chord work to full
blown modern high gain crush.
What’s more the controls are
simple and intuitive to use.
While one should always bear in
mind that taste in tone is a very
subjective matter here follows a
few simple suggestions for getting
some great sounds from your
JTM 30.
Clean: Make sure you select the
Normal channel on the JTM 30.
This is indicated by the green
L.E.D. The strength and height of
your pick-ups will have a great
influence on the level you should
set the volume on this channel
before overdrive sets in. Generally
speaking the volume control
should be set below half way for
totally clean sounds.
Vintage Overdrive: Switch to the
Boost channel which is indicated
by the Red L.E.D. Again pickups
will obviously influence settings
but you will probably find that gain
settings of around 5 or 6 are quite
adequate, the key however is to
increase the master volume level.
As our vintage amps didn’t really
have a lot of pre-amp gain
guitarists used to crank the volume
up to be heard which resulted in
the natural classic Marshall
overdrive roar.
Alternatively the clean Channel
with its volume on maximum gives
a very satisfying vintage type
overdrive.
As far as tone settings go we
would suggest that you start with
the tone controls set at about 5 and
then adjust to taste from there.
Modern Hi-Gain: Switch to the
Boost channel indicated by the Red
L.E.D.
Turn the gain up to full and set the
volume for the desired level. Tone
controls are set to taste, though
probably with the Middle control
lower than the Bass and Treble
controls.
The best advice we could really
offer is to simply experiment and
above all enjoy the pure valve tone
of your Marshall JTM 30.
Front Panel Functions.
1) Footswitch Jack
Jack socket for connection of P801
Footpedal for channel switching.
2) Push Channel Switch
Push switch for panel switching of the
channel. The Push Switch is inoperative
when the Footswitch is connected.
3) Input Jack
Jack socket for the input of the guitar.
4) Volume Control
Controls the Volume of the Normal channel.
5) L.E.D.
Indicates channel. Green-Normal
Red-Boost.
6) Gain Control
Controls the amount of Gain on the Boost
channel.
7) Volume Control
Controls the Volume of the Boost channel.
8) Bass Control
Dictates the amount of low frequency in the
overall tone.
9) Middle Control
Controls the middle frequencies.

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10) Treble Control
Controls the upper or treble frequencies in
your tone.
Note:
The Tone Controls are interactive
and adjusting one can effect the
relative amounts of the others.
Experimentation is the best way of
finding your own personal
favourites.
11) Effects Send Jack
Jack socket for connection to the input of an
external effects processor.
12) Effects Return Jack
Jack socket for the connection from the
output of an external effects processor.
13) Reverb Control
Controls the amount of Reverb on both
channels.
14) Volume
Controls the master or overall volume of the
JTM 30.
15) Standby Switch
Controls the H.T. supply to the valves and
allows the valves to remain heated when not
in use.
16) Power Switch
On/Off switch for mains power to the
amplifier.
Note:
To prolong the life of the valves it
is always advisable to switch on
the Mains Power Switch (item 16)
about 2 minutes before switching
on the Standby (item 15).
This allows the valves to heat up to
full working temperature before
use. On switching off, the Standby
should always be switched before
the Power Switch.
Rear Panel Functions.
1) Mains Fuse
Protects the amplifier and mains supply in
the event of a fault.
2) Mains Input
Connects the amplifier to the mains power
supply.
3) Emulated Output
The Emulated Output captures the tonality
of Vintage loudspeakers like no other D.I.
output. Furthermore this output is
unaffected by the Master Volume control,
therefore allowing the JTM 30’s output to be
turned off whilst still providing silent
recording facilities.
The D.I. output is via an XLR type
connector, which allows this system to be
fed into either (a) a line level balanced input,
(b) a line level unbalanced input or (c) a low
level unbalanced.
✪ Please refer to the following
JTM 30 XLR Out diagram
(Page 6-7) for correct connections.
4) Internal Speaker Output Jack
For connection to internal 16 Ohm speaker.
5) External Speaker Output Jack
For connection to an external 16Ohm
speaker only (such as the Marshall JTM
112C 1x 12” extension cabinet).
Note:
The JTM 30 will deliver 30 Watts
into either one or two 16 Ohm
speakers, ie 16 or 8 Ohm total
impedance. The unit should not be
driven into a load of less than
8 Ohms.

MAINS FUSE
230V—T1.6A
120V—T3A
CAUTION! Replace fuse with same type and
rating only disconnect mains supply before
opening.
ATTENTION! Replacer le fusible par le
meme type et le meme calibre Debrancher a la
prise secteur avant D,ouvrir.
WARNING! No user serviceable parts inside; refer
servicing to qualified personnel only.
AVIS! Risque de choc. Ne pas ouvrir.
WARNING! Fire & Shock Hazard: Do not expose
this unit to rain or moisture. This Apparatus Must Be
Earthed. Do not open.
OUTPUT
EMULATED
OUTPUT
Pin 1—OV
Pin 2—High
Pin 3—Low
Refer to manual
for details Internal Extension
Manufactured in Great Britain by:
Marshall Amplification plc, Bletchley,
Milton Keynes, England.
30 watts RMS into 8/16Ω.
16Ωextension speaker
16Ωinternal speaker
(Refer to manual for details)
MAINS INPUT
230V ~50 Hz
160 Watts
BOOST
VOLUME
STANDBY
0
1
POWER
0
1
FOOT
SWITCH TONE
BASS MIDDLE TREBLE SEND RETURN REVERB VOLUME
LOOP MASTER
VOLUME
INPUT
0
2 8
6
4
10 0
2 8
6
4
10 0
2 8
6
4
10 0
2 8
6
4
10 0
2 8
6
4
10 0
2 8
6
4
10
PUSH
CHANNEL
RED
GREEN
0
28
6
4
10 0
2 8
6
4
10
GAIN
NORMAL
3030
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JTM 30 Front Panel
JTM 30 Rear Panel
JTM 30 XLR Out diagram ✪
1 2 4 6 5 7 9 10 11 12 13 14 15 16 8
34 5
1 2
3
3
2
1
3
2
1
3
2
1
3
2
1
3
2
1
3
2
1
3
2
1
3
2
1
A
B
C
XLR Channel Input On Mixer
(Note: Line Level-Approx OdBV)
2 Core Screened Balanced Mic Lead
Unbalanced XLR to Jack Screened Lead
Unbalanced XLR to Jack Screened Lead
Jack Plug Line Level Jack Input On Mixer Etc.
Jack Plug
NC
NC
Low Level Jack Input On Mixer (ie
Mic Input)