Mesa-Boogie M-pulse Simul State Bass Amplifier User Manual
M
Owner's Manual
ESA
B
OOGIE
Greetings from the Home of Tone
Congratulations on your choice of the M-PULSE as your Bass amplifier and welcome
to the MESA/Boogie family! As a discriminating player you probably know that you
have purchased the most comprehensive instrument for amplifying Bass that is
available. What you might not realize is that this entitles you to all the experience,
resources and commitment our twenty-five years of service to musicians world wide
has to offer. Our responsibility is to help you sound great! So, if at any time you feel
you need help or direction, we are here for you...a phone call away.
Table of Contents
Precautions 0
Overview 1/2
Instant Gratification 2
Helpful Hints 3
FRONT PANEL:
Instrument Inputs: ACTIVE & PASSIVE 4
GAIN 4
BASS 5
MID 5
TREBLE 5/6
PARAMETRIC EQUALIZER 6
GAIN CONTROL: Parametric EQ 6/7
FREQUENCY CONTROLS: Parametric EQ 7
COMPRESSOR 8
THRESHOLD 8
RATIO 8/9
MAIN Output 9
SOLO Output 9
POWER SWITCH 9
REAR PANEL:
FUSE 10
A.C. RECEPTACLE 10
SLAVE OUT 11
SPEAKER OUT 11
DIRECT OUT: LEVEL, POST / PRE, GROUND LIFT and XLR jack 11
EFFECTS: SEND, RETURN, MIX and PROGRAN switch 12
TUNER OUTPUT 12
FOOTSWITCH 12
FACTORY SAMPLE SETTINGS 13/14
TUBE NOISE & DIAGNOSING PRE-AMP TUBE PROBLEMS 15
PERSONAL SETTING PAGES 16/17
PARTS SHEET 18
PRECAUTIONS & WARNINGS
Your MESA/Boogie Amplifier is a professional instrument. Please treat it with respect and operate it properly.
USE COMMON SENSE AND ALWAYS OBSERVE THESE PRECAUTIONS:
WARNING: Vacuum tube amplifiers generate heat. To insure proper ventilation always make
certain there is at least four inches (100mm) of space behind the rear of the amplifier cabinet.
Keep away from curtains or any flammable objects.
WARNING: Do not block any ventilation openings on the rear or top of the amplifier. Do not
impede ventilation by placing objects on top of the amplifier which extend past the rear edge of
its cabinet.
WARNING: Do not expose the amplifier to rain, moisture, dripping or splashing water. Do not
place objects filled with liquids on or nearby the amplifier.
WARNING: Always make certain proper load is connected before operating the amplifier.
Failure to do so could pose a shock hazard and may result in damage to the amplifier.
Do not expose amplifier to direct sunlight or extremely high temperatures.
Always insure that amplifier is properly grounded. Always unplug AC power cord before
changing fuse or any tubes. When replacing fuse, use only same type and rating.
Avoid direct contact with heated tubes. Keep amplifier away from children.
Be sure to connect to an AC power supply that meets the power supply specifications listed on
the rear of the unit. Remove the power plug from the AC mains socket if the unit is to be stored
for an extended period of time. If there is any danger of lightning occurring nearby, remove the
power plug from the wall socket in advance.
To avoid damaging your speakers and other playback equipment, turn off the power of all related
equipment before
making the connections.
Do not use excessive force in handling control buttons, switches and controls. Do not use
solvents such as benzene or paint thinner to clean the unit. Wipe off the exterior with soft cloth.
Be sure to have the warranty card filled out by the store at which it was purchased and return to
Mesa/Boogie.
YOUR AMPLIFIER IS LOUD! EXPOSURE TO HIGH SOUND VOLUMES MAY CAUSE PERMANENT HEARING DAMAGE !
No user serviceable parts inside. Refer service to qualified personnel. Always unplug AC power before removing chassis.
EXPORT MODELS: Always insure that unit is wired for proper voltage. Make certain grounding conforms with local standards.
READ AND FOLLOW INSTRUCTIONS OF PROPER USAGE.
OVERVIEW:
Congratulations on your choice of the
M-PULSE
as your Bass amplifier. This latest offering is our most comprehensive amplifier for
electric bass and it brings together both new and old technology, solid state and vacuum tube design to create an instrument of
unparalleled performance and soulful sound.
M-PULSE
amplifiers start with an all-tube pre-amp for the most musical response and this feeds the three standard rotary tone
controls BASS, MID and TREBLE. Most first time players comment that we could have stopped right there after hearing the sweet,
tight, huge sound from this first section of the
M-PULSE
pre-amp. But that’s just the beginning!
From there, signal is routed to an ultra-powerful 5 Band Parametric Equalizer that has been optimized for the frequencies found on
today’s 5 & 6 string instruments. A bandwidth from 30Hz to 12Khz is found on the 5 frequency controls and each overlaps to assure
a smooth transition between bands. The 5 GAIN controls allow a boost and cut of 15db in either direction to provide 30db of band
specific shaping power. This EQ can be assigned On, Off or Footswitch, which is activated when the
M-PULSE
Footcontroller is
connected. Build a rich, complex, sound utilizing the parametric as your main voice or, add the EQ for a footswitchable solo or slap
sound to an already amazing fundamental tone...either way this 5 Band EQ is a great addition you will come to find invaluable.
Next in the signal path is a new improved Compressor that features both THRESHOLD and RATIO controls. First included on our
2000
Bass amplifier, this updated version allows for much greater fine-tuning of the dynamics. The THRESHOLD control is extremely
M-
sensitive to your attack and can be set for either subtle or dramatic compression effects. The RATIO control allows for anything from
slight dynamic trimming all the way to a hard knee squash with a range from 1:1 to Infinity. The Compressor is also assignable On, Off
or Footswitch giving you the choices of active or inactive all the time or triggering it remotely during a performance as an effect.
After the Compressor we jump over to the Output section that serves up the mighty
SIMUL STATE
power with its awesome 600 (or
360) watts of rich, tube-driven MOSFET tone. This innovative circuit combines the best attributes ot tube and solid state technology to
arrive at a magical blend that breathes and yet, tracks tight while producing massive power.
FRONT VIEW :
ACTIVE
INSTRUMENT
INPUTS
PASSIVE
M- PULSE 600
TM
S I M U L S T A T E B A S S A M P L I F I E R
GAIN BASS MID TREBLE
FOUR - STAGE VACUMM TUBE PREAMPLIFIER
ENGINEERING
0 db 0 0 0 0
ON
OFF
FS
40 Hz 120 400 1.4K 6K
30 90 250 900 4K
SEMI - PARAMETRIC EQUALIZER
PAGE 1
SIMUL STATE POWER
ON
OFF
FS
THRESHOLD RATIO MAIN SOLO
COMPRESSION MASTER VOLUMES
ON
POWER
OVERVIEW:
Continued
This power is interfaced to you via a pair of Output controls that serve as overall MASTER VOLUMES. These are MAIN and SOLO
and the two astound bassists much as they did when we began including them on our guitar amplifiers. The logic is in their names
MAIN and SOLO. When players get this scheme they say “why hasn’t there always been two”. There will be from now on as imitators
follow, but right now we are giving you another footswitchable feature in the form of this SOLO control. This is an additional Master pot
wired in parallel with the MAIN Output and it allows a footswitchable SOLO boost. This feature lets you step out for a showcased part
or allows you to compensate for a sound that has a lower output due to either notching in the Parametric EQ or Compression or both.
Looking to the Rear Panel you can see that all your interfacing needs are well provided for. A dedicated TUNER Output is provided for
tuning without having to disconnect. The Parallel Effects Loop and MIX control provides seamless interfacing of all your outboard
processing. The Loop is also footswitchable allowing you to call up your effects on the fly.
REAR VIEW :
CAUTION
:
Unplug power
before removing fuse or
bolts holding chassis
S
E
U
F
F
U
E
S
POWER FUSE
12A
120 V~
SLO
60 Hz
BLO
12 A
M- PULSE 600
M-PULSE TM SIMUL STATE BASS AMPLIFIER
TUBE DRIVEN-MOSFET POWER
HANDBUILT IN PETALUMA, CALIFORNIA
WARNING
:
To reduce risk of fire or
electric shock, replace fuse with
same type and rating only. Do not
expose this unit to rain or moisture.
WARNING
:
To reduce risk of fire or electric
shock, Do not remove cover. No userserviceable parts inside. Refer
servicing to qualified personnel.
SLAVE OUT
LEVEL DIRECT OUT
SPEAKER OUTPUT
SUGGESTED LOAD
4 OHMS (2 OHM MINIMUM)
LEVEL
GROUND
LIFT
POST
EFFECTS
ON
0% 100%
F.S.
TUNER
SENDRETURN
OUTPUT
FOOT
SWITCH
PRE
A Balanced XLR DIRECT OUTPUT and LEVEL control is provided with both Post and Pre settings to capture your sound through
house main or recording consoles. In addition a SLAVE Output with LEVEL control is provided capturing both pre-amp and power
section in a padded format. This enables you to use additional power for large venues or for deriving a post signal for effects to be sent
to additional amplifier(s) in a 1 dry / 1 wet scenario. And finally, 2 SPEAKER OUTPUTS are provided to harness the robust output of
the
M-PULSE
Now that we have covered the basics of
power amp. With this pair of jacks almost any speaker cabinet or combination of cabinets can be accommmodated.
your
new
M-PULSE,
let’s connect up the A.C. and your favorite cabinet and Bass and give
this instrument of fundamental enlightenment a listen with a quick reference setting.
Instant Gratification:
INSTANT GRATIFICATION (Parametric EQ Optional)
ACTIVE
0 db 0 0 0 0
INSTRUMENT
INPUTS
PASSIVE
Now that you have had a listen to your
GAIN BASS MID TREBLE
FOUR - STAGE VACUMM TUBE PREAMPLIFIER
M-PULSE,
of this manual right now.
ON
OFF
FS
40 Hz 120 400 1.4K 6K
30 90 250 900 4K
SEMI - PARAMETRIC EQUALIZER
here are a few quick tips to help you in case you don’t have time to read the rest
ENGINEERING
PAGE 2
SIMUL STATE POWER
ON
OFF
FS
THRESHOLD RATIO MAIN SOLO
COMPRESSION MASTER VOLUMES
ON
POWER
HELPFUL HINTS:
1. Connect your A.C. Power Cable to a grounded outlet. Avoid ground lifts (3 to 2 prong adapter) whenever possible.
2. The optimum speaker load for your
degradation in tone, however the amplifier will not produce its full rated wattage. Minimum load rating is 2 Ohms and while the
PULSE
of a 2 Ohm load will cause the power mosfets to run hot causing the protection circuit to trigger and mute the output signal until such
time as the mosfets can return to a safe operating temperature. Avoid using 2 Ohm loads whenever possible.
3. Use high quality cable from your instrument to the
should be relatively low capacitance shielded cable. Whenever possible use lengths of 15 feet or shorter. Longer than 15’ tends to
introduce too much capacitance resulting in reduced punch and top end clarity. Speaker cable should be at least 14 gauge (or thicker)
unshielded cable and again try to keep the length of cable as short as possible for the best tonal results.
4. The BASS and TREBLE controls are active type controls with a broad response even though they are acting primarily on their
center frequency Q point. This broader response works extremely well with the passive, broad-band MID control. Because BASS and
TREBLE are active controls, they actually cut (or notch) the region around the Q point when the control is set below 12:00, and boost
these frequencies when the control is set above 12:00. The MID works like a normal passive control and boosts a broad band of
frequencies as it is increased.
5. When using the Parametric EQ keep in mind that cutting (notching) undesirable frequencies is often preferable to boosting desirable ones. By using this technique you will keep noise to a minimum and ensure ample headroom at all times. The Paramet-
ric is a powerful tone shaping tool when used tastefully, but all too often they are abused and set to their extremes which can result in
an unbalanced tone that is “full of holes” or excessive noise.
6. When using the EFFECTS LOOP to patch in your outboard processing, the best sonic results are usually found with the processors’ dry/wet mix set to 100% wet, and the
preserves the integrity of the
dry signal.
will handle this lower load condition - and in fact produce more than its rated power, it is not recommended. Prolonged use
M-PULSEs’
M-PULSE
M-PULSE
tone by mixing in a very small amount of a very wet signal with a high ratio of the original
is 4 Ohms. You may use a cabinet (s) of a higher rating safely (8 Ohm) with no
M-
M-PULSE
EFFECTS MIX control set as close to 10% as possible. Following this scheme
and from the
M-PULSE
to your speaker. Instrument cable
7. The Footcontroller must be connected and SOLO triggered for it to affect the signal.
8. The DIRECT OUTPUT circuit provides a GROUND LIFT that disconnects chassis ground from circuit ground. Should you encoun-
ter a hum or buzz when interfacing to live or recording consoles, try flipping this ground lift after you have muted that channels’ input
or zero’ed the fader. Many times (but not all) the hum is created by a ground loop between the
the
M-PULSE
9. Extreme settings of the Compressor will affect the overall output available, making the amplifier seem not quite as powerful. This
is a result of removing the dynamic content of the signal. May we suggest using the COMPRESSOR tastefully and at less than
extreme settings to attain the best all around performance...unless a desired special effect requires that you disregard more “normal”
settings.
Hopefully these hints have helped get you up and running with your new
tone you have ever heard! Now that you have a better idea of the layout and features, we are ready to move on to understanding the
individual controls and circuits in more detail.
chassis to circuit ground will remedy the situation.
M-PULSE
PAGE 3
and you are well on your way to having the best
M-PULSE
and the console and lifting
FRONT PANEL:
INSTRUMENT INPUTS: ACTIVE / PASSIVE
These are the Instrument Input jacks and between them you can match the
signal output level of virtually any instrument.
The ACTIVE Input is padded down for greater input stage headroom and this works well with basses that use an on-board pre-amp
with an active tone control circuit. Usually these instruments put out a much hotter signal than conventional basses, even when their
tone controls are set “flat”. The added headroom is needed to prevent clipping in the first stage of the pre-amp and the ACTIVE Input
should be used whenever instruments that utilize active style pickup/EQ harnesses are
ACTIVE
used.
ACTIVE
You can use the ACTIVE Input for conventional passive instruments also, for heavy handed
players needing extra headroom or simply a “cleaner” sound. However, note that unless
INSTRUMENT
INPUTS
you have Kong size hands it may be difficult to bring the amplifier to full power with this
INSTRUMENT
INPUTS
reduced front end sensitivity.
PASSIVE
The PASSIVE Input is set up for more conventional basses with passive pickups that pro-
PASSIVE
duce lower output signal levels. This jack is more sensitive than the ACTIVE Input and
therefore can drive the first stage to clip with a much lower signal. Keep this in mind if you
play with a heavy touch or want a little bit of growl or front end clip. In those scenarios this jack can be quite useful to push the first
stage of the pre-amp.
FRONT PANEL CONTROLS:
GAIN:
greater headroom and provide a scooped, brighter personality. The upper harmonics come through more prominently in this area of
the control making the top end sound more transparent and sweet. This region is especially useful for funkier stuff when thumbing is
Fatback feel. The difference in attack and sustain produces striking results as to how the bassist - and in fact the whole band perceives things in the time domain.
This control determines the overall character of the input sensitivity. The lower regions of the control (below 12:00) lend
in order. It keeps the rubber- band feel intact in the lows and mids while voicing the snap just
high enough to avoid harshness, or the dreaded “gak” when the G string is plucked.
ACTIVE
As the GAIN control is increased past 12:00 a richer, more “well-rounded” voice becomes
dominant and headroom starts to diminish in increments until eventually, a tube overdrive
INSTRUMENT
INPUTS
PASSIVE
GAIN BASS
sound appears as the 12AX7 input tube is driven into saturation.
The region between 12:00 and 2:30 is where the classic, warm tube sound resides and
within this narrow band you will discover a world of tone. Tiny increments here produce
FOUR - STAGE VACUMM
subtle, but important differences in the attack characteristic which in turn, feel like changes in
the time domain. By experimenting with the amount of gain, you can actually voice the amp
to feel as if it bounces just ahead of the groove - or lays back a little deeper to produce a more
PAGE 4
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