Ampeg Bass Combo B3158 User Manual

Owner’s Guide
for the
B3 / B328 / B3158
Bass Amplifier
Made in the U.S.A.by 

2
TABLEOFCONTENTS
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...

3
The Front Panel Controls and Their Use
MASTER
-12dB 0 +12dB
5kHz 8kHz 900Hz 2kHz 300Hz 150Hz 600Hz 40Hz 80Hz
-15dB
PA DPEAKONLIMIT
GAINDRIVEBASSULTRA MIDTREBLEINPUT
PULL
EQ ONLO FLAT
HI
EQ
ONBALANCE
LOW HIGH
128765410911312141513
B3/B328/B3158 Bass Amplifier
1. INPUT:The signal output from an instru-
ment (active or passive) or a line level signal
may be connected here by means of a shield-
ed instrument cable.
2. -15dB PAD:This switch, when depressed,
attenuates the input signal by 15dB.
Attenuation...

4
The Front Panel Controls and Their Use
The Rear Panel 
CAUTIONRISK OF ELECTRIC SHOCK
DO NOT OPENAVIS:WARNING: TO REDUCE THE RISK OF FIRE OR 
ELECTRIC SHOCK, SO NO EXPOSE THIS EQUIP-
MENT TO RAIN OR MOISTURE.RISQUE DE CHOC ELECTRIQUE
NE PAS OUVRIR
SPEAKERSEFFECTS
LOOP
BAL.
OUTFOOT
SWITCH RETURN SENDHIGH
50 WATTS
@8 OHMS
8 OHM MIN.LOW
100 WATTS
@4 OHMS
4 OHM MIN.
MODEL
SERIAL #B-3158
500 WATTS MAX.
115VAC-60Hz
POST
PRE
-20dB
0dB
181920232421221617
FOR 100-120VAC, 50/60Hz:       T5A, 250V
FOR 220-240VAC,...

5
21. PRE/POST SWITCH:You can select
either pre or post-EQ for the signal at the
Balanced Out jack (#23) with this switch.
With the switch in the OUT position, the sig-
nal at the jacks will be pre-EQ. This is a
direct output which is not affected by any
EQ or boost settings. With the switch
depressed, the signal is post-EQ and is
controlled and modified by the tone con-
trols, Graphic EQ and Effects Loop.
22. -20dB SWITCH:This switch adjusts theoutput level at the Balanced Out jack (#23).
The switch...

6
GAINDRIVEBASSULTRA MIDTREBLE
GAINDRIVEBASSULTRA MIDTREBLE
GAINDRIVEBASSULTRA MIDTREBLE
GAINDRIVEBASSULTRA MIDTREBLE
Some Suggested Settings*
JAZZ: ROCK:
COUNTRY:
FUNK “POPPING:”B3/B328/B3158 Bass Amplifier
The setting of the
Gain control
depends on your
particular instrument.
The Master control
should be set to pro-
duce the appropriate
output volume level.
The Graphic EQ can
be used to tailor the
amplifier to your
speaker cabinets, to
compensate for
room acoustics and
to “fine tune” your
sound. 

7
Troubleshooting
In the unlikely event that your B3/B328/B3158 should malfunction, take a few minutes to troubleshoot it before you call
for service. You can save yourself time and money by doing it yourself, and often the cure for the problem is something
quite simple.
If the problem isn’t covered above, or if the steps lead you here, then contact your Ampeg dealer for service informa-
tion. Also, you should refer your amp for servicing if it gets dropped, has liquid spilled into it, or sustains damage...

Ampeg reserves the right to change specifications without notice.
Ampeg is proudly Made in America. ©1999 SLM Electronics, 1400 Ferguson Avenue, St. Louis, MO 63133 U.S.A.
P/N 47-588-03 • 10/99
B3/B328/B3158 Bass Amplifier
Technical Specifications
OUTPUT POWER RATING
B3, B328:150 Watts RMS, 4Ωload 
B3158:Low Freq - 100 Watts RMS, 4Ωload 
High Freq - 50 Watts RMS, 8Ωload 
POWER REQUIREMENTS120VAC, 60Hz, 170VA
100/115VAC, 50/60Hz, 170VA
220-240VAC, 50/60Hz, 170VA
TONE CONTROL RANGE
Bass:±8dB @ 50Hz...