Ampeg B3158, B3, B328 User Manual

Owner ’s Guide

for the

B3 / B328 / B3158

Bass Amplifier

Made in the U.S.A. by

2

TABLE OF CONTENTS

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2

Important Safeguards and Precautions . . . . . . . . . .2

The Front Panel Controls and Their Use . . . . . . .3,4

The Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . .4,5

Some Suggested Settings . . . . . . . . . . . . . . . . . . .6

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . .7

System Block Diagram . . . . . . . . . . . . . . . . . . . . . .7

Technical Specifications . . . . . . . . . . . . .back cover

An Introduction to your new Ampeg
Bass Amplifier

Thank you for making one of the best choices you will

ever make for your musical career – choosing one of the
finest bass amps available, an Ampeg B3/B328/B3158.

Y our new bass amplifier of fers many outstanding features.
One hundred fifty watts of pure bass energy, total tone con­trol, and rugged construction make each a true performer’s
bass amp.

Important Safeguards and Precautions

All Ampeg products are designed for continuous safe operation, as long as common sense is used and steps are taken to help
avoid certain problems. Abiding by the following rules can help prevent damage to your amplifier, yourself and others.

• The amplifier is equipped with a three-pronged AC power cord. To reduce the risk of electrical shock, NEVER remove or otherwise
attempt to defeat the ground pin of the power cord.

• Connect the amplifier ONLY to a properly grounded AC outlet of the proper voltage for your amp.

• Avoid sudden temperature extremes, rain and moisture. Also, avoid sudden and intense impact. (If the unit has been subjected to any

of the preceding abuses, have it looked at by an authorized service center.)

• NEVER set the amplifier on a support that might give out under its weight.

• Whenever using tall or stacked speaker cabinets, use them ONLY on a level surface. NEVER set tall or stacked cabinets on a surface

with more than a five degree incline since tipping or falling could occur, possibly causing serious injuries.

• Always keep the total speaker impedance at or above the rated load.

• Unplug the amplifier before cleaning it. NEVER spray liquid cleaners onto the amplifier. Wipe it with a slightly dampened, lint-free cloth

to remove dirt and film.

• Don’t use the amplifier if it has sustained damage to the chassis, controls, or power cord. Refer the unit to an authorized service cen­ter for inspection.

• Amplifiers capable of producing high volume levels are also capable of inflicting permanent hearing loss or damage, if the exposure to
such levels is prolonged. Such damage is progressive and irreversible!

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

CAUTION: TO REDUCE THE RISK OF ELECTRIC SHOCK,

DO NOT REMOVE COVER.

NO USER-SERVICEABLE PARTS INSIDE.

REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.

ATTENTION

RISQUE D'ELECTROCUTION

NE PAS OUVRIR

ATTENTION: POUR REDUIRE D'ELECTROCUTION NE PAS

ENLEVER LE COUVERCLE. AUCUNE PIECE INTERNE N'EST REPRABLE

PAR L'UTILISATEUR. POUR TOUTE REPARATION, S'ADRESSER A UN

TECHNICIEN QUALIFIE.

VORSICHT

ELEKTRISCHE SCHLAGGEFAHR

NICHT OFFENEN

VORSICHT: ZUR MINIMIERUNG ELEKTRISCHER SCHLAGGEFAHR NICHT

DEN DECKEL ABENHMEN. INTERNE TEILE KONNEN NICHT VOM

BENUTZER GEWARTET WERDEN. DIE WARTUNG IS QUALIFIZIERTEM

WARTUNGSPERSONAL ZU UBERLASSEN.

THIS EQUIPMENT HAS BEEN DESIGNED AND ENGINEERED TO PROVIDE SAFE AND RELIABLE OPERATION. IN ORDER TO PROLONG THE LIFE OF THE UNIT AND PREVENT ACCIDEN­TALDAMAGES OR INJURY, PLEASE FOLLOW THESE PRECAUTIONARY GUIDELINES:

WARNING: TO REDUCE THE RISK OF ELECTRIC SHOCK, DO NOT OPEN CHASSIS; DO NOT DEFEAT OR REMOVE THE GROUND PIN OF THE POWER CORD; CONNECT ONLY TO A PROP­ERLY GROUNDED AC POWER OUTLET.

CAUTION: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE THIS EQUIPMENT TO RAIN OR MOISTURE.
CAUTION: NO USER-SERVICEABLE PARTS INSIDE. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
CAUTION: OUR AMPLIFIERS ARE CAPABLE OF PRODUCING HIGH SOUND PRESSURE LEVELS. CONTINUED EXPOSURE TO HIGH SOUND PRESSURE LEVELS CAN CAUSE PERMANENT

HEARING IMPAIRMENT OR LOSS. USER CAUTION IS ADVISED AND EAR PROTECTION IS RECOMMENDED IF UNITIS OPERATED AT HIGH VOLUME. The chart below shows the U.S.
Government Occupational Safety and Health Administration (OSHA) regulations which were in effect at the time of this publication for permissible noise exposure, per 29CRF1910, Table G-16.

According to OSHA, any exposure in excess of those listed above could result in some hearing loss.

"IT IS NECESSARY FOR THE USER TO REFER TO THE INSTRUCTION MANUAL"
"REFERREZ-VOUS AU MANUAL D'UTILISATION"
"UNBEDINGT IN DER BEDIENUNGSANLEITUNG NACHSCHLAGEN"

EXPLANATION OF
GRAPHICAL SYMBOLS:

"DANGEROUS VOLTAGE"
"DANGER HAUTE TENSION"
"GEFAHLICHE SPANNUNG"

=

=

Features

In the world of high performance bass amps, Ampeg amplifiers
stand alone. In true Ampeg tradition, your new B3/B328/B3158
offers you more power, performance and flexibility than any other
bass amplifier in its class. The outstanding features of your new
amplifier, features which set it apart from the competition, are list­ed below:

• 9-BAND GRAPHIC EQ: Use as a “second channel” for bass

solos, or to shape the sound to your own exacting standards. An
independent level control lets you adjust the Graphic EQ volume

• BALANCED LINE OUTPUTS: Independent level control. XLR

type jack to patch into house consoles, mixing boards, or external
power amplifiers

• EFFECTS LOOP: Connect your effects here for increased inten-

sity and quieter operation

• DRIVE CONTROL: To add harmonics for tube-like overdrive

• BALANCE CONTROL (B3158 only): To fine tune the mix

between the Biamp High and Biamp Low outputs

SOUND LEVEL dBA DURATION PER DAY

SLOW RESPONSE IN HOURS

90 8
92 6
95 4
97 3

100 2

SOUND LEVEL dBA DURATION PER DAY

SLOW RESPONSE IN HOURS

102 1-1/2
105 1
110 1/2
115 1/4 or less

B3/B328/B3158 Bass Amplifier

3

The Front Panel Controls and Their Use

MASTER

-12dB

0

+12dB

5kHz 8kHz900Hz 2kHz300Hz150Hz 600Hz40Hz 80Hz

-15dB
PAD

PEAK

ON

LIMIT

GAIN

DRIVE BASS ULTRA MID TREBLE

INPUT

PULL

EQ ON

LO

FLAT

HI

EQ
ON

BALANCE

LOW HIGH

1 2 87654 109 113 12 14 1513

B3/B328/B3158 Bass Amplifier

1. INPUT : The signal output from an instru­ment (active or passive) or a line level signal
may be connected here by means of a shield­ed instrument cable.

2. -15dB PAD:This switch, when depressed,
attenuates the input signal by 15dB.
Attenuation allows the Gain control (#4) to be
used in a more usable (higher) position. If
clipping is indicated with the Gain control at a
low setting, attenuation is needed.

3. PEAK LED: This LED flashes when the
signal level into the preamp approaches clip­ping. Adjust the Gain control (#4) until a
strong signal from your instrument causes
this LED to flicker.

NOTE: If the LED flashes frequently with the
Gain at a low setting, use the -15dB pad (#2)
to attenuate the input signal and readjust the
Gain.

4. GAIN: This serves as the input level con­trol for the amplifier. For the best signal to
noise ratio set this control so the Peak LED
(#3) flashes when you strike a string fairly
hard.

5. DRIVE: This control is used to overdrive
the preamp in order to get various harmonic
enhancement or distorted sounds. In the fully
counterclockwise position the preamp is in
the cleanest condition. As the control is rotat-

ed clockwise, signal level is increased to
drive the preamp harder (into distortion). The
tone of the signal is also changed to provide
a smoother overdrive. (The tone controls may
have to be readjusted to obtain the overall
desired tone.) The Gain control (#4) and ­15dB Pad (#2) interact with the Drive control.
For greater overdrive, the Pad switch should
be out and the Drive control fully clockwise.
Use the Gain control to set the amount of
overdrive desired. The Peak LED (#3) will illu­minate steadily when the amp is used in this
manner.

6. BASS: This is the primary low frequency
control which allows for 12dB of cut or boost
at 50Hz.

7. ULTRA MID: This is the primary midrange
control. Rotate this control to the left of center
for a “contoured” sound (more distant, less
midrange output) or to the right of center for a
pronounced (more up-front) tone.

8. TREBLE: This is the primary high frequen­cy control which allows for 22dB of cut or
17dB of boost at 5kHz.

9. EQ ON LED: This LED illuminates when
the EQ is turned on by either the Master
Control (#11) or a footswitch (#24, rear
panel).

10. GRAPHIC EQ: These sliders control the
output frequencies indicated above each con­trol. The center position of each control is flat
(no boost or cut).

11. MASTER: Set the overall output level of
the amplifier with this control. Pulling this
knob out actives the Graphic EQ (#10). When
a footswitch is connected (#24, rear panel)
this switch is disabled.

12. BALANCE (B3158 only): This control
proportions the output signal between the low
and high frequency output jacks (see #18,
rear panel) when using the amp in the biamp
mode.

13. LIMIT LED(S): The LED illuminates
whenever the amplifier is near full output,
indicating that the internal limiter is keeping
the output from distorting.

NOTE: There are two Limit LEDs only on the
B3158: one for its low frequency power amp
and one for its high frequency power amp.

14. POWER ON LED: This LED indicator illu­minates when the POWER switch (#15) is ON.

15. POWER SWITCH: This heavy-duty rock­er switch applies the power to the amplifier.
The amp is ON when the top of the switch is
depressed, OFF when the bottom of the
switch is depressed.

1. ENTRADA: Conecte aquí su guitarra de bajos
usando un cable blindado para instrumentos.

2. TERMINAL DE -15dB: Si su bajo tiene capta­dores de alta salida ó circuitos electrónicos activos,
usted tal vez notará que el díodo (LED) de Picos
(#3) parpadea ó permanece iluminado aún en posi­ciones bajas del control de Ganancia (#4). Conecte
esta Terminal para conservar limpia la señal. Esto
atenuará la señal de entrada hacia el preamplifi­cador, lo que le permitirá obtener la mejor relación
de señal-a-ruido para su bajo.

3. DIODO (LED) DE PICOS: Este LED se ilumi­nará cuando cualquier etapa de preamplificación se
encuentre cerca del punto de sobreimpulso. Ajuste
el control de Ganancia (#4) hasta que una señal
fuerte de su bajo cause un parpadeo de este LED.

NOTA: Si el LED permanece iluminado aún con la
Ganancia en una posición baja, utilice la Terminal
de -15dB (#2) para atenuar la señal de entrada y
reajuste la Ganancia.

4. GANANCIA: Esto sirve como el control de
nivel de entrada para el amplificador. Para lograr la
mejor relación de señal-a-ruido fije este control para
que el LED de Picos (#3) parpadee cuando usted
pulse con fuerza alguna cuerda.

5. IMPULSO: Este control se usa para sobreim­pulsar el preamplificador a fin de conseguir varios
realces armónicos ó sonidos de distorsión. En la
posición totalmente contraria a las manecillas del
reloj, el preamplificador se encontrará en la posición
más “limpia”. Conforme el control se gire a favor de
las mane-cillas del reloj, el nivel de la señal se incre-

mentará para impulsar el preamplificador con
mayor fuerza (hacia la distorsión). El tono de la
señal también cambia para proveer un sobreimpul­so más suave. Tal vez tengan que ajustarse los
controles de tono para obtener el tono general
deseado. El control de Ganancia (#4) y la Terminal
de -15dB (#2) interaccionan con el control de
Impulso. Para un sobreimpulso mayor, el interruptor
de la Terminal debe estar apagado y el control de
Impulso totalmente a favor de las manecillas del
reloj. Use el control de Ganancia para fijar la canti­dad deseada de sobreimpulso. El díodo LED de
Picos (#3) se iluminará en forma constante cuando
el amplificadora se utilice de esta manera.

6. BAJOS: Esta perilla sirve como el control pri­mordial para las frecuencias bajas. Esto permite un
rango de 8dB de recorte ó de refuerzo a 50Hz.