Marshall Amplification Silver Jubilee Series JCM 25 User manual

BOOK-00143-00
Marshall Amplication plc, Denbigh Road,
Bletchley, Milton Keynes, MK1 1DQ, England.
Telephone: [phone] | Fax: [phone]
Registered in England. Registered Number: 805676
Whilst the information contained herein is correct at the time of publication, due to our policy of constant improvement
and development, Marshall Amplication plc reserves the right to alter specications without prior notice.
marshallamps.com
Jcm 25/50
2555X
sIlVEr
JUBIlEE
rE-IssUE
oWNEr’s maNUal

The Silver Jubilee Series was created in 1987 to celebrate the 25th
anniversary of the founding of Marshall Amplication and 50 years of Jim
Marshall being in the music business. This Limited Edition series of all-
valve ampliers and speaker cabinets looked stunning in silver vinyl
covering, with the amps having chrome-plated control panels.
Based on JCM800 2203 and 2204 Master Volume models, the Silver
Jubilee ampliers were the rst Marshall products to feature a valve output
stage that could be switched from full power to half power. The series
had a somewhat unusual preamp circuit too, featuring three gain ‘modes’
which were ‘Clean’, Rhythm Clip (Boost), and Lead Channel. ‘Clean’ to
Rhythm Clip was controlled by a pull switch, as was the footswitchable
channel change. The Bass, Middle, Treble & Presence controls, although
shared between channels, were re-designed and offered more tonal
variation than any other Marshall product had before.
The Silver Jubilee 2555 head caused a sensation when it was launched in
January 1987 and has since become a collector’s piece. But the real
reason the 2555 acquired legendary status is because of the playing
public, who took it to their hearts. As a result, since it was discontinued in
1988, one of the most common questions we have been asked is, “when
are you going to re-issue the Silver Jubilee 2555?” So, by popular
demand, we have created the 2555X, which is a modern re-issue of the
2555 head, with exactly the same sonic characteristics and functionality.
Introduction
“Thanks are due to you and the veritable army of musicians
who by their appreciation of, and skill in using Marshall
Ampliers over the years, have helped us to create this
memorable Jubilee Series.”
- Jim Marshall, 1987.
The above is the late, great Jim Marshall quoted from the original Silver
Jubilee owner’s manual. The sentiment he expressed then is extended to
you now for choosing to purchase the 2555X – our thanks are indeed due
to you. We hope you enjoy your new 2555X.
- The Marshall Team
1. Input Jack
Plug in here to connect your guitar to the amplier.
2. Input Gain Control/Rhythm Clip
The Input Gain control adjusts the overall sensitivity of the input circuit. It
controls the gain level of the clean/crunch Rhythm mode. The pull switch
function activates the Rhythm Clip mode, providing heavier, more driven
tones. N.B. The apparent drop in volume when Rhythm Clip mode is
selected may be overcome by increasing the level of the Output Master
(No. 5).
3. Lead Master
When the Lead Channel is active (No. 5) the Lead Master adjusts the
output level of the Lead Channel.
4. Lead Channel L.E.D.
Indicates red when the Lead Channel is selected.
5. Output Master Control/Lead Channel
The Output Master controls the output of the preamp section to the power
stage. The Lead Channel is selected using the footswitch (supplied).
The channels can also be switched by using the push/pull function of the
Output Master control. The amount of gain applied to the Lead Channel
can be controlled using the Input Gain control (No. 2)
6. Treble Control
Adjusts the amount of upper frequencies in the sound.
7. Middle Control
Adjusts mid-range frequencies in the sound. High settings will provide a
fatter sound by boosting the mids. Lower settings cut the mids, providing a
more ‘scooped’ sound, accentuating the Treble and Bass frequencies.
8. Bass Control
Adjusts the low frequency content of the sound.
9. Presence Control
This is a power amp function which adjusts the ‘brightness’ of the whole
amplier in conjunction with the Treble control.
Front panel functions
123456789101112

RETURNSEND
MAINS INPUT
230V ~ 50Hz
375 WATTS
FUSE
230V - T2AE250V
100-130V - T4AE250V
MODEL: 2555X
1 x 16 OHM
“CLASS 2 WIRING”
CONNECT SPEAKERS BEFORE USE
OUTPUT: 100 WATTS RMS
LOUDSPEAKERS
FX LOOP
1 x 8 OHM
2 x 16 OHM
1 x 4 OHM
2 x 8 OHM
HT FUSE
T1AE250V
FOOTSWITCHD.I.
10. Output Power Switch
This switches power from High Output (100 Watts) to Low Output (50
Watts). The Low Output setting recongures the four output EL34 valves
from Pentode (High) to Triode (Low) mode. Switching from High to Low
not only halves the 2555X’s power output, it also results in a slightly
warmer, less ‘in your face’ tone.
11. Standby Switch
The Standby switch is used in conjunction with the Power switch (item 12)
to ‘warm up’ the amplier before use and to prolong the life of the output
valves. When powering up the amplier always engage the Power switch
rst, 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 be used
to turn the amplier on and off during breaks in performance. Also, when
switching power off, always disengage the Standby switch prior to the
main Power switch.
12. Power Switch
This is the On/Off switch for the mains power to the amplier. When it is
switched on the switch will light red. Please ensure that the amplier is
switched off and unplugged from the mains electricity supply before being
moved.
Front panel functions (cont.)
13. Mains Input
Connects the amplier to the mains power supply.
14. H.T. Fuse
Replace only with the fuse value shown on the panel.
15. FX Loop
Series FX Loop connects the amplier to external FX (approximately
-10dBV level). The Send jack connects to the FX input jack and the Return
jack connects to the FX output jack.
16. Footswitch Jack Socket
Connects remote channel-switching footswitch (supplied).
17. D.I.
Frequency compensated line level output for feeding directly into slave
ampliers or mixing desks.
18. Loudspeaker Output Jacks
There are ve speaker outputs available. They are labelled according to
the intended impedances:
16Ω: connect a 16 Ohm guitar cabinet to this jack.
8Ω: connect a single 8 Ohm guitar cabinet or two 16 Ohm cabinets.
4Ω: connect a single 4 Ohm guitar cabinet or two 8 Ohm guitar cabinets.
WARNING - Although the 2555X amplier has ve speaker outputs, never
attempt to connect more speakers than rated.
The safe combinations are: 1 x 16 Ohm, 1 x 8 Ohm, 1 x 4 Ohm, 2 x16
Ohm or 2 x 8 Ohm. Any other speaker conguration may stress the power
amplier section and in extreme cases may lead to valve and/or output
transformer failure. NEVER use the 2555X without a (speaker) load
attached when the Standby switch is ON.
Rear panel functions
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WARNING: Before going any further, make sure that your amplier is
compatible with your electrical supply. If you have any doubt, please seek
help from a qualied technician – your Marshall dealer can help you in this
respect.
Mains Input & Fuse: Your amplier is provided with a detachable mains
(power) lead which should be connected to the Mains Input socket on the
rear panel of the amplier.
The specic mains input voltage rating that your amplier has been
manufactured for is indicated on the rear panel of the amplier.
The correct value and type of mains fuse is specied on the rear panel of
the amplier.
NEVER attempt to bypass the fuse or t one of the incorrect value or type.
Transporting your equipment: Please ensure that your amplier is
switched off, unplugged from the mains electricity supply and all
removable cables have been disconnected from your equipment before
attempting to move it.
Important set up information:
1. Make sure that the cabinet(s)/speakers, where appropriate, are
connected to the correct impedance Loudspeaker jack(s) on the rear
panel of the amplier. See the speaker output guides in this handbook for
specic information regarding impedance matching (Rear Panel Functions
#16). When using an extension cabinet make sure that you are using a
proper speaker cable. Never use a screened (shielded) guitar cable for
this purpose.
2. Ensure the Volume controls on the front panel are set to zero.
3. Connect the supplied mains (power) lead into the Mains Input on the
rear panel rst and then into the electrical outlet.
4. Plug your guitar into the Input jack socket on the front panel.
5. Turn the front panel Power switch on and wait a couple of minutes
before going to point number 6.
6. After waiting, engage the Standby switch (see Front Panel Functions
#11 for a full explanation).
7. Turn the Volume controls up to your preferred level and your amp is
ready to play.
WARNING! Important safety instructions Notes.