Ampeg Bass heads SVP150H User Manual

							Owner’s Guide
for the
SVT-150H
Bass Amplifier
Made in the U.S.A.
by 
						

							SVT-150H
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 Diagram  . . . . . . . . . . . . . . . . . . . . . .7
Technical Specifications  . . . . . . . . . . . . .back cover
An Introduction to your new Ampeg
SVT-150H Bass Amplifier
First of all, thank you for making what could be one of
the best choices you could ever make concerning your
musical career - choosing one of the finest bass amplifiers
available, an Ampeg SVT-150H.
Your new bass amplifier offers you many outstanding
features, such as 150 watts of pure bass energy, total tone
control and rugged construction which make it a true per-
former’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, NEVERremove or otherwise
attempt to defeat the ground pin of the power cord.
•Connect the amplifier ONLYto 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 preceeding abuses, have it looked at by an authorized service center.)
•NEVERset the amplifier on a support that might give out under its weight.
•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 cen-
ter 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! 
CAUTIONRISK 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.
ATTENTIONRISQUE DELECTROCUTION
NE PAS OUVRIR
ATTENTION: POUR REDUIRE DELECTROCUTION NE PAS
ENLEVER LE COUVERCLE. AUCUNE PIECE INTERNE NEST REPRABLE
PAR LUTILISATEUR. POUR TOUTE REPARATION, SADRESSER A UN
TECHNICIEN QUALIFIE.
VORSICHTELEKTRISCHE 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 UNITAND PREVENT ACCIDEN-
TAL DAMAGES 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 PROP-
ERLY 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 UNIT IS 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 DUTILISATION
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 SVT-150H offers you
more power, performance and flexibility than any other bass ampli-
fier in its class. Here are just some of the outstanding features of
your new amplifier - features which set it apart from the competi-
tion!
•9-BAND GRAPHIC EQ:Use as a “second channel” for bass solos, or to
shape your sound to your own exacting standards.
•BALANCED LINE OUTPUT:XLR with independent level control switch
to patch into house consoles, mixing boards, or external power amplifiers.
•EFFECTS LOOP:For increased intensity and quieter operation of exter-
nal effects.
•DRIVE CONTROL:To add harmonic content for tube-like overdrive. 
SOUND LEVEL dBA DURATION PER DAY
SLOW RESPONSE IN HOURS
90 8
92 6
95 4
97 3
100 2SOUND LEVEL dBA DURATION PER DAY
SLOW RESPONSE IN HOURS
102 1-1/2
105 1
110 1/2
115 1/4 or less 
						

							SVT-150H
3
The Front Panel Controls and Their Use
1234567891011121314
1. ENTRADA:Conecte aquí su guitarra de bajos
usando un cable blindado para instrumentos.
2. TERMINAL DE -15 dB:Si su bajo tiene capta-
dores de alta salida ó circuitos electrónicos activos,
usted tal vez notará que el díodo (LED) de Picos
(#3) parpadea ó permanece iluminado aún en posi-
ciones bajas del control de Ganancia (#4). Conecte
esta Terminal para conservar limpia la señal. Esto
atenuará la señal de entrada hacia el preamplifi-
cador, lo que le permitirá obtener la mejor relación
de señal-a-ruido para su bajo.
3. DIODO (LED) DE PICOS:Este LED se ilumi-
nará 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 -15 dB (#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 sobreim-
pulsar 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 seincrementará para impulsar el preamplificador con
mayor fuerza (hacia la distorsión). El tono de la
señal también cambia para proveer un sobreimpul-
so 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 -15 dB (#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 canti-
dad 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 pri-
mordial para las frecuencias bajas. Esto permite un
rango de 8dB de recorte ó de refuerzo a 50Hz.
1. INPUT:Connect your bass guitar here
using a shielded instrument cable.
2. -15dB PAD:If your bass has high-output
pickups or active electronics you may notice
the Peak LED (#3) flashes or stays on even at
low settings of the Gain control (#4). To keep
the signal clean, switch in the Pad. This will
attenuate the input signal to the preamp allow-
ing you to get the best signal to noise ratio for
your bass.
3. PEAK LED:This LED lights whenever any
preamp stage is near the point of being over-
driven. Adjust the Gain control (#4) until a
strong signal from your bass causes this LED
to flicker.
NOTE:If the LED stays on with the Gain at a
low setting, use the 15dB Pad (#2) to attenu-
ate 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 distortion sounds. In the fully
counterclockwise position the preamp is in the
cleanest condition. As the control is rotatedclockwise, 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 glow steadily
when the amp is used in this manner.
6. BASS:This knob serves as the primary low
frequency control. This allows for a range of
8dB of cut or boost at 50Hz.
7. ULTRA-MID:This is the primary midrange
control. Rotate the control to the left of center
for a “contoured” sound (more distant, less
midrange output) or to the right of center for a
sound that really cuts through.
8. TREBLE:This knob serves as the primary
high frequency control. This allows for a range
of 17dB boost or 22dB cut at 5kHz.
9. EQ ON LED:This LED indicator lights
when you engage the EQ by the front panel
Master control (#11) or the footswitch (#23,
rear panel).10. GRAPHIC EQ:These slide controls allow
you to adjust the output of the frequencies
shown beside each control. The center posi-
tion of each control is flat (no boost or cut).
These controls only affect the sound when the
EQ is turned on.
11. MASTER:Set the overall output level of
the amplifier with this control. The Effects
Loop and Balanced Out (#18, 19, 22) are not
affected by the Master control. Pulling the
Master control turns on the Graphic EQ (#10).
When the footswitch is used, the front panel
switch is bypassed.
12. LIMIT LED:This LED indicator will flash
on any time the internal limit circuit is called
upon to keep amplifier’s output signal clean.
This indicates that the amplifier is nearing full
output and the limiter is keeping it from clip-
ping the output signal.
13. POWER ON LED:This LED indicator
lights when the POWER switch (#14) is
turned on.
14. POWER SWITCH:This heavy-duty rock-
er switch applies AC power to the amplifier:
the amp is ON in the up position, OFF in the
down position. 
						

							7. ULTRA-MEDIANOS: Este es el control primor-
dial para el rango de las frecuencias medianas. Gire
el control del centro hacia la izquierda para lograr
un sonido de contorno (más distante, menor salida
en el rango mediano) ó del centro hacia la derecha
para obtener un sonido realmente penetrante.
8. AGUDOS:Esta perilla sirve como el control pri-
mordial para las frecuencias altas. Esto permite un
rango de 17 dB de refuerzo ó 22dB de recorte a
5kHz.
9. EQ EN LED: Este LED indicador se ilumina
cuando usted activa el EQ mediante el control
Maestro (#11) del panel delantero ó el interruptor de
pie (#23) del panel posterior.10. EQ GRAFICO:Estos controles deslizantes
(cursores) le permiten ajustar la salida de las fre-
cuencias que se muestran junto a cada control. La
posición central de cada control es plana (sin
refuerzo ni recorte). Estos controles sólo afectan el
sonido cuando el EQ esé prendido.
11. MAESTRO: Fije mediante este control el nivel
general de salida del amplificador. El Circuito de
Efectos y la Salida Equilibrada (#18, 19, 22) no se
verán afectadas por el control Maestro. Jalando el
control Maestro se prende el EQ Gráfico (#10).
Cuando se utiliza el interruptor de pie, se pasa por
alto el interruptor del panel delantero.12. DIODO LED DE LIMITE:Este LED indicador
parpadeará cada vez que se requiera el circuito lim-
itador interno para conservar limpia la señal de sal-
ida del amplificador. Esto indica que el amplificador
está aproximándose a su salida máxima y que el
limitador está impidiendo el aplanamiento (“clip-
ping”) de la señal de salida.
13. DIODO LED DE POTENCIA ENCENDIDA:
Este LED indicador se ilumina cuando se prende el
interruptor de POTENCIA (#14).
14. INTERRUPTOR DE POTENCIA: Este interrup-
tor de servicio pesado tipo vaivén aplica la energía
de CA al amplificador:  el amplificador se PRENDE
en la posición hacia arriba, y se APAGA en la posi-
ción hacia abajo 
SVT-150H
4
The Front Panel Controls and Their Use
The Rear Panel 
161517 18 1920212223
Made in the U.S.A. by SLM ELECTRONICS
1400 Ferguson Avenue  •  St. Louis, MO 63133
15. FUSE:This protects the unit from dam-
age due to overload conditions or power
line surges. If the fuse blows, replace it only
with the same size and type.
16. AC LINE IN:Firmly plug the supplied
AC power cord into this socket, pushing it in
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!
17. SPEAKER OUTPUT(S):The SVT-
150H has two 1/4” speaker output jacks
which you will use to connect to your bass
cabinet(s). Use speaker cables with 1/4”
plugs to connect the SPEAKER jack(s) to
the cabinet(s). Observe the 4 ohm minimum
impedance rating. Please see the note
concerning the speaker output jacks on
the facing page.
The following chart shows the total
impedance load when connecting speaker
cabinets in parallel:
Cabinet # of Total
Impedance Cabs Impedance
8Ω24Ω
16Ω28Ω
16Ω44Ω
18. EFFECTS RETURN:To use an external
effects device or other signal processor,
connect the OUTPUT of the device to this
jack using a shielded cable. This feeds the
processed signal into the amplifier’s master
section.
19. EFFECTS SEND:Connect the output
from this jack to the INPUT of an external
effects device using a shielded cable. This
sends a post-EQ signal to your effects.
Since plugging a cable in here does not
break the through connection to the power
amp, this can be used as another line out.
20. PRE/POST SWITCH:You can select
either pre or post-EQ for the signal at the
Balanced Out jack (#22) 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 in, the
signal is post-EQ and is controlled and
modified by the tone controls, Graphic EQ
and Effects Loop.21. -20dB SWITCH:This switch adjusts the
output level at the Balanced Out jack (#22).
The switch works independently from the
front panel Master control. Pushing the
switch in activates the -20dB pad, allowing
patching into microphone inputs on a mixer
without overdriving them.
22. BALANCED OUT:This XLR-type con-
nection supplies a balanced preamp output
signal for connecting to a house mixing
board, recording console or external ampli-
fiers with balanced inputs. The signal can be
set to pre or post-EQ by the Pre/Post switch
(#20). The level can be adjusted for either
mic or line type inputs using the -20dB
switch (#21).
23. FOOTSWITCH:This jack accepts the
1/4” plug from a 1-button footswitch, allow-
ing remote control of the Graphic EQ on/off
function. When a footswitch is used, the
front panel Master Pull EQ On switch (#11)
is bypassed. 
						

							15. FUSIBLE:Esto protege a la unidad con-
tra daños debidos a condiciones de sobrecar-
ga 
ósobretensiones transitorias en la línea de
energía. Si el fusible se quema, repóngalo
sólo con el mismo tipo y tamaño.
16. ENTRADA DE LA LINEA DE CA:
Conecte firmemente a este receptáculo el
cable suministrado de corriente de CA, oprim-
iéndolo hasta que quede totalmente asenta-
do. Enchufe el extremo macho del cord
ón a
una salida aterrizada de CA.  ¡NO PASE POR
ALTO EL BORNE DE TIERRA DE LA CLAV-
IJA DE CA!
17. SALIDA(S) DE LA(S) BOCINA(S):El
SVT-150H tiene dos “jacks” de salida para
bocinas que usted usará para conectarse a
su(s) gabinete(s) de bajos. Use cables para
bocinas con clavijas de 1/4” para conectar el
(los) “jack(s)” de la(s) BOCINA(S) al (los)
gabinete(s). Observe la especificaci
ón de 4
ohms de impedancia mínima.
La tabla a continuaci
ón muestra la carga
de impedancia total cuando se conecten gabi-
netes de bocinas en paralelo: 
Impedancia de # de Impedancia
cada Gabinete Gabinetes Total 
8 ohms 2 4 ohms
16 ohms 2 8 ohms
16 ohms 4 4 ohms
18. RETORNO DE EFECTOS:Para utilizar
un dispositivo de efectos externo ú otro proce-
sador de señales, conecte la SALIDA del dis-
positivo a este “jack” usando un cable blinda-
do. Esto alimenta la señal procesada a la sec-
ci
ón maestra del amplificador.
19. ENVIO DE EFECTOS:Conecte la salida
de este “jack” a la ENTRADA de un dispositi-
vo de efectos externo usando un cable blinda-
do. Esto envía una señal post-EQ a sus efec-
tos. Siendo que la conexi
ón de un cable en
este lugar no rompe la conexión directa al
amplificador de potencia, esto se puede uti-
lizar como otra linea hacia afuera.
20. INTERRUPTOR PRE/POST:Usted
puede seleccionar por medio de este inter-
ruptor ya sea pre 
ópost-EQ para la señal en
el “jack” de Salida Equilibrada (#22). Con el
interruptor en la posición de FUERA, la señal
en los “jacks” será pre-EQ. Esta es una salida
directa no afectada por ningunas posiciones
del EQ ó de refuerzo. Con el interruptor hacia
adentro, la señal es post-EQ y se controla y
modifica mediante los controles de tono, el
EQ Gráfico y el Circuito de Efectos.
21. INTERRUPTOR DE -20dB:Este interrup-
tor ajusta el nivel de salida en el “jack” de
Salida Equilibrada (#22). El interruptor fun-
ciona independientemente del control
Maestro del panel delantero. Al oprimirse el
interruptor hacia adentro se activa la terminal
de los -20dB, lo que permite conectarse a las
entradas para micrófonos en un mezclador
sin sobreimpulsarlos.22. SALIDA EQUILIBRADA:Esta conexión
tipo XLR proporciona una señal de salida
equilibrada de preamplificación para conec-
tarse a un tablero mezclador local, una con-
sola  grabadora ó amplificadores externos
con entradas equilibradas. La señal se puede
establecer como pre ó post-EQ mediante el
interruptor Pre / Post (#20). El nivel se puede
ajustar para entradas de tipos ya sean de
micrófono ó de línea utilizando el interruptor
de -20dB (#21).
23. INTERRUPTOR DE PIE:Este “jack”
acepta la clavija de 1/4” de un interruptor de
pie de un solo botón, lo que permite un con-
trol remoto de la función de prender / apagar
del EQ Gráfico. Cuando se utiliza un interrup-
tor de pie, se pasa por alto el interruptor
Maestro para Prender ó Jalar el EQ (#11).
SVT-150H
5
The Rear Panel
NOTE: In some areas 1/4” speaker jacks are
not acceptable for use on amplifiers capa-
ble of high output power levels. For this rea-
son the Speaker jacks on your amplifier
may resemble the illustration to the right.
Connect the amplifier to your speaker(s)
using cables rated for very high output
power, terminated with the appropriate con-
nectors. 
						

							SVT-150H
6
Some Suggested SettingsThe setting of the Gain control depends on your particular instrument. The
Master should be set to produce 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.
JAZZ: ROCK:
COUNTRY:
FUNK “POPPING:” 
						

							SVT-150H
7
Troubleshooting
In the unlikely event that you SVT-150H should stop working properly (or just stop working), take a few minutes to trou-
bleshoot it before you call for service. You can save yourself a lot of time and sometimes 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 led 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 to its
power cord (see page 2).
System Block Diagram
TONES9 BAND EQ PEAK LED
INPUT
GAIN
-15dBDRIVE
BASS
ULTRA MIDTREBLE
FOOT
SWITCH
EFFECTS 
SENDEFFECTS 
RETURN
EQ ON
MASTER
PRE
-20dB2
3 POST
SPEAKER
OUTS
SPEAKON®JACK
POWER
AMP
LIMIT LED
BALANCED
OUT
1+
1–
NO SOUND
LEDs LIGHT
POOR SOUND
Check bass, cables
Check speaker(s)
Replace speaker(s)
POOR SOUND
LEDs DONT LIGHT
Check AC outlet
NO SOUND
NO HUMHUM
Listen for hum
NO CHANGE
SOUND OK
SOUND OK
POOR SOUNDSOUND OK
SOUND OK
SOUND OK
Check amp controls, check
for signal from bass
Check power cord,
fuse, power switchCheck house fusebox
or circuit breakerSPEAKER(S) OK,
POOR SOUNDSPEAKER(S)
DEFECTIVE
Check speaker Unplug bass,
touch tip of cable
LOUD HUM
Check inst. pickup
Speaker OK
Replace cable
NO CHANGE
SEE BELOWSEE BELOW
NO OUTLETOUTLET OK
OK 
						

							P/N 47-588-52  .
01/97
Ampeg reserves the right to change specifications without notice.
Ampeg is proudly Made in America. ©1997 SLM Electronics, 1400 Ferguson Avenue, St. Louis, MO 63133 U.S.A.
SVT-150H
Technical Specifications
OUTPUT POWER RATING 150 Watts RMS, 4Ωload, 115VAC 
POWER REQUIREMENTS
Domestic: 115VAC, 60Hz, 140VA
Export: 100/115VAC, 50/60Hz, 140VA
230VAC 50,60Hz, 140VA
TONE CONTROL RANGE
Bass: ±8dB @ 50Hz
Ultra-Mid: +5, -17dB @500HZ
Treble: +17, -22dB @ 5KHZ
GRAPHIC EQ RANGE
40Hz ±11dB
80Hz ±8dB
150Hz ±8dB
300Hz ±8dB
600Hz ±8dB
900Hz ±8dB
2kHz ±8dB
5kHz ±9dB
9kHz ±12dB
GAIN 66dB typical, tones @ center
SIGNAL TO NOISE RATIO 75dB typical 
SIZE (W x H x D) AND WEIGHT 19”x9.5”x12.5”, 30 lbs