Marshall Amplification DBS 7400 User manual

HAND
BOOK
BASS
DYNAMIC
SYSTEM

ENGLISH
1
FROM THE CHAIRMAN
I would like to thank you personally for
selecting one of our Dynamic Bass systems.
My company has always been totally
committed to the design and manufacture of the
worlds finest amplification.
We are well aware that catering for the
constantly changing demands of musicians
requires heavy investment into the research and
development of new product ranges capable of
meeting those demands. The new Marshall
Dynamic Bass System comes as a direct result
of that investment.
The innovative circuitry that forms the heart of
the amplifier required many hours of dedicated
and painstaking research and much consultation
with bass players of international stature.
Equally the production of the matching cabinet
range, required all the accumulated
manufacturing skills that we have acquired over
the past three decades.
We set out with only one objective in mind, that
was to re-define what a bass system should be.
This we have achieved and you are now the
owner of the remarkable resulting system.
Please be sure to read this handbook carefully
before operating your new Dynamic Bass
System.
Sincerely

2
WARNING!
PLEASE READ THE FOLLOWING LIST CAREFULLY.
A. ALWAYS fit a good quality mains plug conforming to the latest B.S.I. standards
(UK only).
B. ALWAYS wire the plug in accordance with the colour code attached to the mains lead (UK
only).
C. DO NOT attempt to remove the amplifier chassis. There are no user serviceable parts
inside.
D. ALWAYS have this equipment serviced or repaired by competent, qualified personnel.
E. NEVER under any circumstances, operate the amplifier without an earth.
F. NEVER use any amplifier in damp or wet conditions.
G. ALWAYS ensure that the impedance of the speaker or speakers connected does not fall
below the amplifiers minimum impedance rating.
H. NEVER obstruct the ventilation grills.
I. ALWAYS use Marshall D.B.S speaker leads.
J. PLEASE READ this instruction manual carefully before switching on.
Constant exposure to the high sound pressure levels of which this amplification system
is capable could result in permanent damage to your hearing.
Although individuals will vary in their susceptibility to noise induced hearing loss,
almost everyone will have their hearing impaired if exposed to intense sound levels
for a sufficient length of time.
To prevent the occurance of permanent hearing loss, it is advisable to wear ear plugs or protectors if you
are going to be exposed to high noise levels for prolonged periods.
INTRODUCTION
The Marshall Dynamic Bass System was carefully designed using innovative new circuitry to provide you
with a combination of superb sensitivity and excellent control plus incredible levels of dynamic power to
project and respond to the full range of contemporary bass sounds.
Superb sensitivity comes from the fully blendable mixture of a valve or solid state input pre-amp. The
solid-state section offers fast, percussive attack, as favoured by many modern players, whilst the single
ECC83 valve provides the smooth warmth and more compressed classic tone exclusive only to valve
technology.
Excellent control is derived from comprehensive EQ and compression facilities including primary EQ,
where Low and Hi rotary tone controls combine with deep and bright switches to give amazing depth and
clarity to your basic sound. More precise tone shaping or the ability to set up a completely contrasting
sound, is available from the switchable 9 band graphic EQ, which has been tailored to cut and boost those
frequencies that are fundamental to dynamic bass performance. The built in compressor provides further
control and features industry standard technology for smooth operation and the highest performance
quality.
Knowing how important headroom and clean power are to accurate, powerful bass reproduction led our
designers to engineer a system with headroom that goes far beyond the normal limits. Whereas a
conventional bass amplifier has an RMS to peak power ratio of 1:2, the Marshall Dynamic Bass System
dramatically increases this ratio to 1:10, giving you five times more headroom than an ordinary bass
amplifier.
The result is a no compromise bass system with an RMS rating of 400 watts capable of delivering peaks
of 4000 watts. This ensures that the system has the energy to respond accurately to even the widest
dynamic range.
In sound terms this extended headroom provides incredible clarity and punch to give you the most
responsive, rewarding bass amplification system that you've ever played through.
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3
USING THE DYNAMIC BASS SYSTEM
Make all the external connections such as the send (26) and return (27) to and from your effects processor,
the output to your guitar tuner (25) and connection to the footswitch for the graphic EQ (20) if required.
If you are extending the system by linking to a further D.B.S. amplifier, take a screened guitar cable from
the link-out jack (22) of the controlling amplifier to the link-in jack (21) of the slave system.
Check that the Speakon connectors are fully located, twisted and locked at both the cabinet and amplifier
ends (see diagram) before switching on your D.B.S amplifier. Note: (When systems are linked together
always switch on the master system before switching on the slave system and vice versa on switching off).
Select the correct input to match your bass.
Generally speaking the low-sensitivity input (2) suits bass guitars of high output levels e.g. active basses
and the high sensitivity input (1) suits lower output instruments (passive basses). As there are so many
different output levels from the many types of instrument available to you, you should try both before
making the decision.
Set the primary EQ to flat and make sure that the deep (6), bright (5), compression (10) and graphic EQ
switches (14) and the master volume control (15) are all off.
By turning the Gain control (3) until the peak LED lights occasionally you will be setting the optimum
level of input gain. Too little means that the amp is working inefficiently, too much can cause unwanted
distortion.
The gain control (3) may need to be backed off accordingly if you boost the EQ, especially in the lower
frequencies.
Note: (Even with the gain control off you will still get a sound through the speakers on turning up the
master volume).
Turn up the master volume to the desired level and set-up your basic sound using the primary EQ controls
(7&8) combined with the deep and bright switches (5 & 6). The character of the sound can be changed
using the pre-amp blend control (4) from the brighter more percussive solid state tone to the warmer more
compressed vintage valve tone.
When using the built in compressor the compression threshold is set using the gain control (3) and the
amount of compression by the depth control (11).
The clean power of the D.B.S is so dynamic that you may not need any further EQ although any amount
of fine tuning of tone can take place using the 9 band graphic equaliser. Alternatively you can set-up an
entirely different sound on the graphic then use the footswitch to switch between the two. This incredible
clarity also means that you won’t have to compromise your EQ settings as the volume increases , as is often
the case with normal bass amplification.
SPEAKON CONNECTORS
1.Ensure locking ring (A) is rotated fully Anti-clockwise. Insert Speakon connector into socket and align
key ways.
2. Rotate body of the connector (B) fully Clock-wise.
3. Rotate locking ring (A) Clock-wise to it's full extent.
Note: (Reverse above procedure to remove connector).
MOUNTING THE 7400 IN A RACK
Though your 7400 Dynamic Bass System amplifier comes supplied in a purpose built 3U sleeve, it is also
rack mountable. As with all rack mount products of substantial weight, we strongly recommend that you
ensure that it is adequately supported using suitable brackets at the rear as well as the front.
(See Rear Panel diagram for positions of fixing bolts).
A
B
ENGLISH

4
MODEL 7400 FRONT PANEL
FUNCTIONS.
1. Hi-sensitivity Input
Input for the connection of bass guitars with
lower output levels.
2. Lo-sensitivity Input
Input for the connection of bass guitars with
higher output levels.
3. Gain Control with Peak LED
Controls the level of input gain.
For optimum signal level the peak LED should
light occasionally.
4. Pre-Amp Blend Control
This control fully anti-clockwise routes the
signal through purely solid state input pre-amp
circuitry. Turned fully clockwise the signal is
routed through an ECC83 pre-amp valve circuit.
The various positions in between offer numerous
combinations of the brighter more percussive
solid-state tone with that of warmer more
compressed valve tone.
5. Bright Switch
Push switch to add brightness and attack to the
top end of the primary EQ.
6. Deep Switch
Push switch to add extra bottom to the low end
of the primary EQ.
7. Low Primary EQ Control
Rotary control that gives + or - 15dB cut and
boost of the lower end of the primary EQ.
8. High Primary EQ Control
Rotary control that gives + or - 15dB cut or
boost of the primary EQ upper frequencies.
9. Compression Threshold Indicator
LED which indicates when the compression
threshold is reached.
10. Compression On/Off Push Switch
Push switch which activates the compression
circuit.
11. Compression Depth Control
Rotary control for selecting the depth of
compression. Note: (This control works in
conjunction with input gain control (3)). The
input Gain control should be used to set the
threshold level and the depth control to select the
amount of compression.
12. Graphic Equaliser
9 Band graphic equaliser offering + or - 15dB
cut or boost (centre flat) of the frequencies that
proved to be the most effective for bass
reproduction in our exhaustive listening tests.
13. Graphic EQ Master Level
Master level slider offering + or - 6dB cut or
boost (centre 0dB) of the overall graphic level.
This allows the accurate balancing between the
levels with or without the graphic switched in.
14. Graphic On/Off Switch and Indicator
Push switch to access or by-pass the graphic
with LED indicating on/off status. (The graphic
is also footswitchable by any standard on/off
footswitch).
For the footswitch to function the front panel
switch must be in the ‘On’ position).
15. Volume Control
Rotary control to set the overall output level of
the amplifier.
16. D.I. Pre or Post EQ Selection Switch
Selection switch to offer a studio or PA engineer
with the choice of direct signal either before or
after EQ and compression has been added.
17. Power Switch
On\ Off mains power switch with LED indicator
and featuring soft start circuitry to minimise
switch on and switch off noise.
MODEL 7400 REAR PANEL
FUNCTIONS.
18. Mains Input Connector
For connection to mains power supply.
19. Twin Speaker Outputs
Heavy duty locking type sockets for connection
to loudspeakers. The minimum total load is 2
Ohms.
As Dynamic Bass System cabinets are rated at 4
Ohms, combinations of two cabinets provide the
optimum load.
20. Graphic Footswitch Jack
Jack socket for the connection of a single
On/Off footswitch for the Graphic EQ.
21. Link In Jack
Jack socket to accept the Link output signal
from another Dynamic Bass System amplifier
when extending the system.
22. Link Out Jack
Jack socket to feed the Link input of another
Dynamic Bass System amplifier when extending
the system. Note: (The Link in and the Link out
jacks are optimised for linking Marshall
Dynamic Bass System amplifiers only).
ENGLISH

ENGLISH
THE CABINET RANGE
Using the finest materials, construction techniques and specially custom designed loudspeakers, we have
created a range of extraordinary bass cabinets which perfectly complement the power and performance of
the Dynamic Bass System.
The loudspeakers required highly specialised research, to enable them to handle the high continuous power
levels and awesome power peaks that the Dynamic Bass System is capable of producing.
These custom speakers all feature specially reinforced cone systems, high temperature voice coils and
massive magnet assemblies, all housed in ultra rugged cast chassis.
Connections to the cabinets are via heavy-duty locking sockets to ensure a safe, no loss high powered
termination.
Each cabinet is ported and carefully tuned to its matching speakers and integrates perfectly with other
models in the range to cover the entire spectrum of bass sounds.
Model 7410 4x10 with Horn (800 watts RMS -4 Ohms).
This cabinet has an unusually deep bass response for it’s type. Superb transient attack is provided by the
high frequency horn which features a 6 position attenuator control, from the horn fully off at one extreme to
the horn fully on at the other extreme.
The 7410's tight and punchy performance totally suits upfront modern styles of bass playing.
Dimensions - Height 698mm x Width 698 mm x Depth 380mm.
Model 7412 4x12 (800 watts RMS -4 Ohms).
Recognising the enormous potential that the 4x12 cabinet has to offer for bass, considerable engineering
time was devoted to the specially designed speakers and cabinet of the 7412.
Combining many of the best characteristics of the 2x15 and 4x10 cabinets together, the 7412 has plenty of
bottom end with rapid transient attack. This is the ideal cabinet for playing situations requiring a single
speaker cabinet with maximum tonal response.
Dimensions - Height 1000mm x Width 698mm x Depth 489mm.
Model 7215 2x15 (600 watts RMS -4 Ohms).
The model 7215 features drive units designed to achieve superb, high sensitivity bass response.
In addition to forming the foundation of a serious bass system when combined with either the 7410 or
7412, this unit’s complementary balanced high end provides enough presence and attack to allow it to be
used on its own.
Dimensions - Height 1000mm x Width 698mm x Depth 489mm.
Note: (The RMS power handling figures are for comparison only when used with non Dynamic Bass
System amplifiers. The peak capacity of these cabinets is individually matched to the performance of the
Dynamic Bass System amplifier).
23. D.I. Level Selection Switch
Selects 0dB or -20dB D.I. output levels for
maximum interfacing flexibility.
24. Balanced D.I. Output
For direct connection to recording or PA mixing
desks and switchable pre or post EQ (16).
The D.I. output is fully transformer isolated to
guarantee against problems with earth loops and
hence an earth lift switch is not required.
25. Tuner Output Jack
Instrument level buffered output for direct
connection to an electronic tuner.
26. Effects Send Jack
Jack socket to connect to the input of an external
effects processor.
27. Effects Return Jack
Jack socket to accept the output from an external
effects processor. Note: (The output level of the
effects loop is nominally centred around + 4 dB
which makes it compatible with most rack effects
processors).
28. Line Level Control
Rotary control providing level control of the line
out from zero to +4dB.
29. Line Output Jack
Jack socket ideal for connection to home
recording equipment.
5

Front Panel
Rear Panel
DYNAMICS BASS SYSTEM
POWER
DEEP
BRIGHT
GRAPHIC
ONPEAK
INPUT
D.I. PRE
POST
HI LO
FLAT
+15dB
-15dB
+6dB
-6dB
0dB
HILO
DEPTH
ON
-15 +15
. .
S V
. .. . -15 +15 . .
. .
PRIMARY EQ COMPRESSIONGAIN PRE-AMP
BLEND VOLUMEGRAPHIC EQUALIZER
LEVEL50 80 160 320 640 1250 2500 5000 8000
S-SOLID STATE
V-VALVE THRESHOLD
MIN MAX
. .
12 16 17
34 567 8 91011 12 1314 15
MAINS INPUT
230V ~ 50Hz
900 VA GRAPHIC
FOOTSWITCH
LINE OUTPUT LINE
LEVEL (dBm)
+4
-∞
EFFECTS
RETURN EFFECTS SEND TUNER OUT
LINK IN LINK OUT D.I. LEVEL
0dBm (out)
-20dBm (in) BALANCED D.I.
OUTPUT
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
Manufactured in Great Britain by:
Marshall Amplification plc, Bletchley, Milton Keynes.
MINIMUM LOAD 2 OHMS
(400 Watts R.M.S.)
NE RAS UTILISER SANS HALT-
PARLEUR
SPEAKER OUTPUTS
18 19 20 21 22 23 24
29 28 27 26 25
Rear fixings for support brackets when rack mounted (4 off)