Owner’s Guide
for the
V4BH
Bass Amplifier
Made in the U.S.A. by
V4BH Bass Amplifier
2
Table of Contents
Important Safeguards and Precautions . . . . . . . . . . . . . .2
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
System Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . .3
The Front Panel Controls and Their Use . . . . . . . . . . . . .4
The Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Some Suggested Settings . . . . . . . . . . . . . . . . . . . . . . . .6
Changing the Tubes . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Technical Specifications . . . . . . . . . . . . . . . . . .back cove
r
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-prong 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. If no grounded outlet is available, use only
an approved method of adapting to a two-prong AC source.
• 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.
• Always keep the total impedance at or above the rated load.
• Unplug the amplifier before cleaning it. NEVER spray liquid cleaners onto the unit. Wipe the unit 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 is advised and ear protection recommended when playing at
extremely loud levels.
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.
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
IMPORTANT SAFETY INSTRUCTIONS
• READ, FOLLOW, HEED, AND KEEP ALL INSTRUCTIONS AND WARNINGS.
• DO NOT OPERATE NEAR ANY HEAT SOURCE AND DO NOT BLOCK ANY VENTILATION OPENINGS ON THIS APPARATUS. FOR PROPER OPERATION, THIS UNIT REQUIRES 3”
(75CM) OF WELL VENTILATED SPACE AROUND HEATSINKS AND OTHER AIR FLOW PROVISIONS IN THE CABINET.
• DO NOT USE THIS APPARATUS NEAR SPLASHING, FALLING, SPRAYING, OR STANDING LIQUIDS.
• CLEAN ONLY WITH LINT-FREE DAMP CLOTH AND DO NOT USE CLEANING AGENTS.
• ONLY CONNECT POWER CORD TO A POLARIZED, SAFETY GROUNDED OUTLET WIRED TO CURRENT ELECTRICAL CODES AND COMPATIBLE WITH VOLTAGE, POWER, AND
FREQUENCY REQUIREMENTS STATED ON THE REAR PANEL OF THE APPARATUS.
• PROTECT THE POWER CORD FROM DAMAGE DUE TO BEING WALKED ON, PINCHED, OR STRAINED.
• UNPLUG THE APPARATUS DURING LIGHTNING STORMS OR WHEN UNUSED FOR LONG PERIODS OF TIME.
• ONLY USE ATTACHMENTS, ACCESSORIES, STANDS, OR BRACKETS SPECIFIED BY THE MANUFACTURER FOR SAFE OPERATION AND TO AVOID INJURY.
• WARNING: TO REDUCE THE RISK OF ELECTRIC SHOCK OR FIRE, DO NOT EXPOSE THIS UNIT TO RAIN OR MOISTURE.
• SERVICE MUST BE PERFORMED BY QUALIFIED PERSONNEL.
• OUR AMPLIFIERS ARE CAPABLE OF PRODUCING HIGH SOUND PRESSURE LEVELS. CONTINUED EXPOSURE TO HIGH SOUND PRESSURE LEVELS CAN CAUSE PERMA-
NENT HEARING IMPAIRMENT OR LOSS. USER CAUTION IS ADVISED AND EAR PROTECTION IS RECOMMENDED IF UNIT IS OPERATED AT HIGH VOLUME.
• WARNING: THIS UNIT REQUIRES A SAFETY GROUNDED OUTLET WIRED TO CURRENT ELECTRIC CODES HAVING THE LINE SUPPLY VOLTAGE, POWER, AND FREQUENCY
IDENTIFIED ON THE REAR OF THE UNIT. THE OUTLET MUST REMAIN ACCESSIBLE TO DISCONNECT THE UNIT IF A FAULT SHOULD ARISE WHILE IN USE. THIS UNIT SHOULD
BE UNPLUGGED WHEN NOT IN USE.
CAUTION
RISK OF ELECTRIC SHOCK
DO NOT OPEN
WARNING: TO REDUCE THE RISK OF FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE
THIS APPARATUS TO RAIN OR MOISTURE. TO REDUCE THE RISK OF ELECTRIC
SHOCK, DO NOT REMOVE COVER. NO USER-SERVICEABLE PARTS INSIDE. REFER
SERVICING TO QUALIFIED SERVICE PERSONNEL.
PRECAUCION
RIESGO DE CORRIENTAZO
NO ABRA
PRECAUCION: PARA REDUCIR EL RIESGO DE INCENDIOS O DESCARGAS ELECTRICAS, NO PERMITA QUE ESTE APARATO QUEDE EXPUESTO A LA LLUVIA O LA HUMEDAD. PARA DISMINUOIR EL
RIESGO DE CORRIENTAZO. NO ABRA LA CUBIERTA. NO HAY PIEZAS ADENTRO QUE EL USARIO
PUEDO REPARAR DEJE TODO MANTENIMIENTO A LOS TECHNICOS CALIFICADOS.
ATTENTION
RISQUE D'ELECTROCUTION
NE PAS OUVRIR
ATTENTION: PROTÉGEZ CET APPAREIL DE LA PLUIE ET DE L'HUMIDITÉ AFIN D'ÉVITER TOUT
RISQUE D'INCENDIE OU D'ÉLECTROCUTION. 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.
"IT IS NECESSARY FOR THE USER TO REFER TO THE INSTRUCTION MANUAL"
“ES NECESARIO QUE EL USUARIO SE REFIERA AL MANUAL DE INSTRUCCIONES.”
"REFERREZ-VOUS AU MANUAL D'UTILISATION"
EXPLANATION OF GRAPHICAL SYMBOLS:
EXPLICACION DE SIMBOLOS GRAFICOS:
EXPLICATION DES SYMBÔLES GRAPHIQUES:
"DANGEROUS VOLTAGE"
“VOLTAJE PELIGROSO”
"DANGER HAUTE TENSION"
=
=
V4BH Bass Amplifier
3
An Introduction to your new Ampeg V4BH Bass Amplifier
The harmonically rich sound and legendary performance of the classic AMPEG SVT are redefined in the V4BH.
This dynamically powerful bass amp delivers a thunderous 100 watts of unsurpassed quality, reliability and tonal
flexibility. It also provides the classic vibrance of tubes as well as contemporary features. The features and controls
of your V4BH are covered in detail within the pages of this owner’s guide. We recommend going over them before
you use the amplifier.
Features
In true Ampeg tradition, your new V4BH offers you more power, performance and flexibility than any other bass ampli-
fier in its class. Below are some of the outstanding features of your new amplifier – features which set it apart from the
competition! Additional information on these features can be found on the pages indicated.
• -15dB INPUT: This feature is perfect for “active” basses (page 4)
• ULTRA LO AND ULTRA HI SWITCHES: These enable you to tailor your sound in many different ways at
the touch of a button (page 4)
• 5-POSITION FREQUENCY SELECTOR: Take your pick from the five center frequency points to get just the
right midrange voice (page 4)
• SLAVE OUT: Use for powering another amp from the V4BH’s preamp (page 5)
System Block Diagram
0dB INPUT
GAIN
ULTRA
LO
MID
FREQUENCY
MASTER
BUFFER
PREAMP
OUT
PWR AMP
INPUT
SLAVE
OUT
BAL
OUT
SPEAKER
OUT
EXT.
SPEAKER
OUT
POWER
AMP
PWR/STDBY LED
ULTRA
HI
-15dB INPUT
BASS TREBLE
4 OHMS8 OHMS
IMPEDANCE
SPEAKON*
JACK
1+
2+
1- 2-
*Speakon is a registered trademark of Neutrik U.S.A.
4
The Front Panel Controls and Their Use
V4BH Bass Amplifier
Hi
Lo
Ultra Hi / Lo
15dB
0dB
Standby/
Power
1. 0dB INPUT: The signal output from an
instrument (active or passive – typically
passive) or a line level signal may be connected here by means of a shielded instrument cable. The signal at this jack is sent
into the preamp at full strength.
2. -15dB INPUT:
The signal output from
an instrument (active or passive – typically
active) or a line level signal may be connected here by means of a shielded instrument cable. The signal at this jack is
padded 15dB before it is sent into the preamp.
3. GAIN: This control adjusts the basic
level of signal in the preamp.
4. ULTRA HI: This switch boosts high
frequencies.
5. ULTRA LO: This switch, when
depressed, provides emphasis to the
low frequencies by boosting the low
frequencies and selectively cutting the
mid frequencies.
6. BASS: This is the primary low frequency control. It allows for 12dB of
cut or boost at 40Hz.
7. MIDRANGE: This is the primary
midrange control. It allows for 20dB of
cut or 10dB of boost at the center frequency selected by the Frequency
control (8).
8. FREQUENCY: Allows you to select
the center frequency for the Midrange
control (7), giving you a choice of five
“voices” for the Midrange. The numbers
correspond to the following center frequencies as indicated: 1=220Hz,
2=450Hz, 3=800Hz, 4=1.6kHz, 5=3kHz.
9. TREBLE: This is the primary high
frequency control. It allows for 20dB of
cut or 15dB of boost at 4kHz.
10. MASTER: This controls the signal
level to the power amp and therefore the
overall listening level. It also controls the
level to the Preamp Out jack (20).
11. STANDBY/POWER LED: This is a
dual-function LED. In Standby Mode, it
glows red. In the On mode (when high
voltage is applied to the tubes) it glows
green. If it does not turn green in the
On mode, there is no high voltage
present and the unit needs servicing.
12. STANDBY: The Standby mode
allows the tubes to warm up or remain
warm without high voltage being
applied to them. This extends tube life.
This switch should be OFF when first
turning the amplifier on. Allow the unit
to warm up for 20 seconds before
switching to the ON position. During
short periods of non-use, the amp
should be put into Standby mode.
13. POWER: This supplies AC power
to the unit. Turn this switch on before
turning on the Standby switch (12), as
explained above.
3
5
5
6
6
4
4
3
3
7
7
2
2
1
1
–15dB
0dB
Hi
8
8
9
9
010
010
Lo
Ultra Hi / Lo
Gain Bass Midrange Frequency Treble Master Standby Power
4
3
2
1
010
5
5
6
6
4
3
7
2
8
1
9
010
1 2 3 4 5 6 7 8 9 10 1211 13
4
2
5
1
7
8
9
4
3
2
1
010
5
5
6
6
4
3
7
8
9
2
1
010
7
8
9
Standby/
Power
5
The Rear Panel
V4BH Bass Amplifier
14. FUSE: This protects the unit from
damage due to overload conditions or
power line surges. If the fuse blows,
replace it only with the same size and
type.
15. AC LINE IN: Firmly insert the supplied AC power cord into this socket
until it is fully seated. Plug the male
end of the cord into a grounded AC
outlet. DO NOT DEFEAT THE
GROUND PRONG OF THE AC
PLUG!
16. PREAMP OUT: This jack carries
the post-Master (10) signal. Using this
jack does not break the path to the
power amp. This signal can be used to
feed an external power amplifier, mixing console or house PA system.
17. POWER AMP IN: This jack
accepts a signal to be sent to the
power amp and the Slave Out jack
(18). Using this jack breaks the path
from the signal that was present at the
Preamp Out jack (16). This can be
used as a post-Master (10) patch
point.
18. SLAVE OUT: This jack receives
the same signal that is being sent to
the power amp. It is useful for powering another amp (slave) from this unit’s
preamp. It can also be used as an
“unbalanced” version of the Balanced
Out (19) signal.
19. BALANCED OUT: This XLR jack is
the preamp output. Thus, it will include
any processing done in the Preamp
Out/Power Amp loop (16,17). This signal can be used to feed an external
power amplifier, mixing console or
house PA system.
20. PRESENCE SWITCH: When this
switch is depressed a high fequency
boost is added to the output signal.
This helps compensate for a speaker
cabinet with no high frequency driver,
adding a glassy top end to the sound.
21. SPEAKER OUT: Two 1/4” phone
jacks are provided for connecting
speakers to the unit. These jacks are
wired in parallel. Use the jack on the
right (“Main”) first. The jack on the left
should only be used to connect a second speaker cabinet.
NOTE: In some areas 1/4” speaker jacks are
not acceptable for use on amplifiers with
high output power levels. For this reason the
1/4” jacks on your amplifier may be sealed. If
this is the case, use the Speakon®jack to
connect the amplifier to your speaker cabinet. Use a heavy duty speaker cable terminated with the proper connectors.
22. IMPEDANCE SELECTOR: Use
this switch to match the output impedance of the amp to the speaker(s)
being used (4 or 8 ohms). For help in
deciding the total impedance of your
system, consult the chart below.
Cabinet Number of Total
Impedance
Cabinets Impedance
4 ohms 1 4 ohms
8 ohms 1 8 ohms
8 ohms 2 4 ohms
16 ohms 2 8 ohms
16 ohms 4 4 ohms
Speakon®is a registered trademark of
Neutrik U.S.A.
14 181716 19 20 222115
V4BH Bass Amplifier
6
Some Suggested Settings
FUNK:
JAZZ:
ROCK:
COUNTRY:
The setting of the
Gain control
depends on your
particular instrument.
The Master should
be set to produce
the appropriate
output volume level.
5
5
6
6
4
4
3
3
7
7
2
2
1
1
010
010
Gain Bass Midrange Frequency Treble Master
8
8
9
9
Hi
Lo
Ultra Hi / Lo
4
3
2
1
010
IN
7
7
8
8
9
9
IN
Hi
Lo
Ultra Hi / Lo
4
3
2
1
010
5
5
6
6
4
4
3
3
2
2
1
1
010
010
Gain Bass Midrange Frequency Treble Master
IN
3
5
6
7
8
9
5
6
7
8
9
5
4
3
2
1
010
5
4
3
2
1
010
6
7
8
9
6
7
8
9
4
2
1
5
5
4
3
2
1
010
6
7
8
9
5
4
3
2
1
010
6
7
8
9
3
4
2
1
5
5
4
3
2
1
010
6
7
8
9
5
4
3
2
1
010
6
7
8
9
5
5
4
4
3
3
2
2
1
1
010
010
Gain Bass Midrange Frequency Treble Master
5
5
4
4
3
3
2
2
1
1
010
010
Gain Bass Midrange Frequency Treble Master
3
5
6
6
7
7
Hi
8
8
9
9
Lo
4
3
2
1
010
6
7
8
9
5
4
3
2
1
010
6
7
8
9
4
2
1
5
5
4
3
2
1
010
6
7
8
9
5
4
3
2
1
010
6
7
8
9
Ultra Hi / Lo
3
5
6
6
7
7
Hi
8
8
9
9
Lo
4
3
2
1
010
6
7
8
9
5
4
3
2
1
010
6
7
8
9
4
2
1
5
5
4
3
2
1
010
6
7
8
9
5
4
3
2
1
010
6
7
8
9
Ultra Hi / Lo
IN
V4BH Bass Amplifier
Changing the Tubes
The performance characteristics of tubes are degraded in direct proportion to how often and under what conditions
the amplifier is used. Power tubes should be checked at least once a year - more frequently if you use the amplifier
nearly every day. When power tubes wear out, the amplifier will begin to grow weak, lack punch, fade up and down,
or lose highs and lows. Power tubes work together in a push/pull configuration and should all be replaced at the same
time with matched or balanced tubes. Your dealer can recommend the best replacement tubes for your amplifier.
Preamp tubes typically last longer than power tubes. When a preamp tube wears out, the amplifier may squeal, get
noisy, lose gain and sensitivity, or just quit working. A service center can determine which tube(s) may need replacing.
To gain access to the power tubes in the V4BH, the rear panel must be removed. Tube replacement should only
be performed by a qualified service person.
• Turn the amp off, unplug it and let it cool for at least 5 minutes.
• Remove the screws which hold the panel to the rear of the cabinet.
• Set the panel aside.
• Gently pull the tube retainer away from the base of the tube.
• Grasp the tube at its top and gently work it out of its socket by rocking it slightly back and forth as you pull on it.
• When inserting new output tubes, align the tab in the tube’s plastic base with the slot in the socket and press
the tube gently but firmly into place by pushing down on its top. (Preamp tubes have a “missing pin” which correspondes with the “missing hole” in the socket – line up the missing pin and hole before pressing the tube into
its socket.)
• Make sure that each tube retainer firmly grips the base ot the tube.
• Replace the rear panel and tighten its screws.
• Power up the amplifier and let it sit for at least 20 minutes. Bias the amplifier per the schematic (qualified tech-
nicians only!).
7
In the event that your V4BH should stop working properly, or just stop working, take a few minutes to troubleshoot it
before you call for service. You can save yourself time and money doing it yourself, and often the problem is something
quite simple. Please refer to the Troubleshoointg Diagram below for guidelines. Symptoms of tube failure are defined
above.
If the problem isn’t covered above, or if the steps lead you here, then contact your Ampeg dealer for service information. Also, you
should refer your amp to an authorized service center for servicing if it gets dropped, has liquid spilled into it, or sustains damage to
its power cord.
Troubleshooting
Troubleshooting Diagram:
NO SOUND
LEDs LIGHT
Check amp controls, check
for signal from bass
NO SOUND
Listen for hum
NO HUM HUM
Check speaker Unplug bass,
Speaker OK
SOUND OK
touch tip of cable
NO CHANGE
SOUND OK
Replace cable
LEDs DON'T LIGHT
Check AC outlet
Check power cord,
fuse, power switch
NO POWEROUTLET OK
Check house fusebox
or circuit breaker
OK
POOR SOUND
Check bass, cables
POOR SOUND
Check speaker(s)
SPEAKER(S) OK,
POOR SOUND
POOR SOUND SOUND OK
SOUND OK
SPEAKER(S)
DEFECTIVE
Replace speaker(s)
NO CHANGE
SEE BELOW SEE BELOW
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 47-509-42 • 092805
V4BH Bass Amplifier
www.ampeg.com
Technical Specifications
OUTPUT POWER RATING 100 watts RMS minimum continuous @ <3% THD into 4 or 8Ω, 0.7VRMS input
TOTAL SYSTEM GAIN 59dB @ 1kHz with levels up and tones flat, -3dB @ 30Hz and 12kHz
TONE CONTROL RANGE
BASS: ±12dB @ 40Hz
MIDRANGE: +10dB, -20dB @ 220, 450, 800, 1.6k or 3kHz
TREBLE: +15dB, -20dB @ 4kHz
ULTRA LOW: +2dB @ 40Hz, -10dB @ 500Hz
ULTRA HIGH: +9dB @ 8kHz
PRESENCE: +6dB @ 10kHz
SIGNAL TO NOISE RATIO 80dB typical
TUBE COMPLEMENT (2) 12AX7, (2) 12AU7, (4) 6L6/5881
POWER REQUIREMENTS 115VAC, 60Hz, 190VA; 100/115VAC, 50/60Hz, 190VA; 230VAC, 50/60Hz, 190VA
SIZE (W x H x D) AND WEIGHT 23-3/4” W x 11” H x 12-3/4” D, 40 lbs.
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