Mesa-Boogie Walk About Bass Amplifier User Manual

Owner's Manual

ESA

OOGIE

Greetings from the Home of Tone

Congratulations on your choice of the WalkAbout 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.

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: EU: permission from the Supply Authority is needed before connection.

WARNING:

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.

Vacuum tube amplifiers generate heat. To insure proper ventilation always make

WARNING:

impede ventilation by placing objects on top of the amplifier which extend past the rear edge of its cabinet.

WARNING:

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.

Do not block any ventilation openings on the rear or top of the amplifier. Do not

Do not expose the amplifier to rain, moisture, dripping or splashing water. Do not

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.

Table of Contents

Precautions 0 Overview 1/2

Instant Gratification 2

Helpful Hints 2/3

FRONT PANEL:

Instrument Inputs: ACTIVE & PASSIVE 3

CONTROLS: GAIN 4 BASS 4 MID 5 TREBLE 5 DI LEVEL 6 MASTER 6 PARAMETRIC EQUALIZER 6/7 FREQUENCY CONTROLS 7

REAR PANEL:

FUSE 8 A.C. RECEPTACLE 8 DIRECTOUT: Post / Pre - Ground Lift - XLR Jack 8 EFFECTS LOOP: Send & Return 9 SPEAKER OUTPUT 9

FACTORY SAMPLE SETTINGS 10 PERSONAL SETTINGS PAGE 11 TUBE NOISE and DIAGNOSING PRE-AMP TUBE PROBLEMS 12 PARTS SHEET 13

OVERVIEW:

Operating Instructions

Congratulations on your choice of the

and

360

600

delivers all the tone and most of the features in a package thats bound for the open road.

At the heart of this giant killer is a robust 300 watt

M-Pulse WalkAbout

Simul-State

Bass Amplifier! This compact and powerful little brother to the

M-Pulse

power section that will handle most clubs and smaller venues with surprising headroom. This tube driven mosfet design combines the best qualities of both tube and solid state technology to achieve a lightweight, reliable platform that is supremely musical. This toneful power is metered out with the MASTER control, and can be used to drive any two speaker cabinets via the two SPEAKER OUTPUT jacks, with a combined overall load of 4 Ohms being the preferred impedance. Should you find yourself in larger venues, an XLR Balanced Direct output with a convenient Front Panel DI LEVEL control enables you to send your choice of pre or post signals to the board for Front Of House reinforcement.

WalkAbout

The

Preamp is a four stage, all-tube, finely-tuned instrument of shaping power for bass. The signal path begins with the Input jacks and both ACTIVE and PASSIVE instruments have been provided for with a dedicated jack. The front end GAIN control determines the amount and color of preamp signal and/or drive you wish to push through the rotary Tone Controls. Active shelving

FRONT VIEW: WalkAbout

ACTIVE

INSTRUMENT

INPUTS

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

0 db 0 0

-15 + - + - +15

60 Hz 340Hz 2K

E N G I N E E R I N G

TREBLE DI LEVEL MASTER

PASSIVE

FOUR - STAGE VACUUM TUBE PREAMPLIFIER

REAR VIEW: WalkAbout

CAUTION

Unplug power before removing fuse or bolts holding chassis

POWER FUSE

120 V~

SLO

60 Hz

BLO

6 A

DIRECT OUT

GROUND

LIFT

WARNING

PRE

POST

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.

30 300 200 2K 1.2K 12K

PARAMETRIC EQUALIZER

M-PULSE

WALKABOUT

SIMUL STATE BASS AMPLIFIER TUBE DRIVEN-MOSFET POWER

HANDBUILT IN PETALUMA , CALIFORNIA

EFFECTS LOOP

RETURN SEND

E N G I N E E R I N G

SPEAKER OUTPUT

SUGGESTED LOAD

4 OHMS

WARNING

To reduce risk of fire or electric shock, Do not remove cover. No userserviceable parts inside. Refer servicing to qualified personnel.

PAGE 1

POWER

OVERVIEW:

Continued

type BASS and TREBLE controls are combined with a passive style MID to produce a powerful string of musically interactive and comprehensive tone controls. If even further tweaking is desired, we have included a 3 Band Semi-Parametric Equalizer that covers frequencies between 30Hz and 12Khz. This in-line EQ assures that any sound you can dream of can be dialed in quickly and accurately. The three bands sensible Q points make for ease of understanding and the FREQUENCY controls overlap to allow pinpoint accuracy in the regions where the controls meet. And finally, a series EFFECTS LOOP patch point between the preamp and the power section.

Now that you have an overview of the controls and features of your new

WalkAbout

, let’s move on to understanding each of them

individually so that you can dial in your own personal sound quickly and easily.

Instant Gratification:

ACTIVE

INSTRUMENT

INPUTS

PASSIVE

GAIN BASS MID

FOUR - STAGE VACUUM TUBE PREAMPLIFIER

S I M U L S T A T E B A S S A M P L I F I E R

0 db 0 0

-15 + - + - +15

60 Hz 340Hz 2K

30 300 200 2K 1.2K 12K

PARAMETRIC EQUALIZER

TREBLE DI LEVEL MASTER

E N G I N E E R I N G

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

WalkAbout

degradation in tone, however the amplifier will not produce its full rated wattage. Minimum load rating is 2 Ohms and while the

WalkAbout

will handle this lower load condition - and in fact produce more than its rated power, it is not recommended. Prolonged use 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

cable 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 shelving 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,

is 4 Ohms. You may use a cabinet (s) of a higher rating safely (8 Ohm) with no

WalkAbout

PAGE 2

and from the

WalkAbout

to your speaker. Instrument

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