User's Guide for the
User's Guide for the
Bass Preamp
Bass Preamp
Ampeg® is Proudly Made in America
Ampeg
®
is Proudly Made in America
2
TABLE OF CONTENTS
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Important Safeguards and Precautions . . . . . . . . . . . . . . .3
The Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
The Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
System Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Important Information About Tubes and Tube Products . . .6
Some Suggested Settings . . . . . . . . . . . . . . . . . . . . . . . . .7
Technical Specifications . . . . . . . . . . . . . . . . . . .back cover
SVP-PRO Bass Preamp
IMPORTANT SAFETY INSTRUCTIONS
• READ, FOLLOW, HEED, AND KEEPALL 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 BYTHE 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.
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 SYMBÔLESGRAPHIQUES:
"DANGEROUS VOLTAGE"
“VOLTAJE PELIGROSO”
"DANGER HAUTE TENSION"
=
=
3
An Introduction to your new Ampeg SVP-PRO Bass Preamp
The harmonically rich sound and legendary performance of the AMPEG SVT are redefined in the SVP-PRO. This
dynamic preamp delivers unsurpassed quality, reliability and tonal flexibility, offering the classic vibrancy of tubes as well
as contemporary features. The SVP-PRO is the preamp section of our much-respected SVT -2 PRO. All of the features and
controls of your SVP-PRO are covered in detail within the pages of this user’s guide. We recommend going over them
before you use the preamp.
Features
In the world of high performance bass amps, Ampeg’s SVT amplifiers stand alone. Keeping with true Ampeg tradition,
the SVP-PRO Bass Preamp offers you more performance and flexibility than any other preamp in its class. Listed below
are some of the outstanding features of your new preamp - features which set it apart from the competition! Additional information on these features can be found on the pages indicated.
• PAD: A switchable attenuator pad, this feature is perfect for basses with active electronics or very “hot” pick-
ups (page 4).
• MUTE SWITCH: Lets you cut the sound from the amp, letting you tune your bass in private (page 4).
• ULTRA LOW, ULTRA HIGH AND BRIGHT SWITCHES: Lets you tailor your sound in many different ways
“with the touch of a button” (page 4).
• 5-POSITION MIDRANGE SELECTOR: Take your pick from the five center frequency points available to get
just the right midrange voice (page 4).
• 9-BAND GRAPHIC EQ: Use as a “second channel” for bass solos, or to shape your sound to your own exact-
ing standards. An independent level control lets you adjust the Graphic EQ volume. Switchable at front panel or
with a footswitch (page 4).
• TRANSFORMER BALANCED LINE OUT JACK: For connection to a recording console, PAsystem or external
power amplifier. Switchable for Pre- or Post-EQ operation (page 5).
SVP-PRO Bass Preamp
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 equipment, yourself, and others.
• The unit 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 unit ONLY to a properly grounded AC outlet of the proper voltage for your unit.
• 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 unit on a support that might give out under its weight.
• Unplug the unit before cleaning it. NEVER spray liquid cleaners onto the unit. Wipe it with a slightly dampened, lint-free cloth to
remove dirt and film.
• Do not use the unit if it has sustained damage to the chassis, controls, or power cord. Refer the unit to an authorized service cen-
ter for inspection.
• Audio equipment 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! Consider using quality hearing protection devices.
4
SVP-PRO Bass Preamp
The Front Panel:
1. INPUT: Use this jack to connect your
bass to the preamp by means of a shielded
instrument cable.
2. MUTE: This switch, when depressed,
mutes the signal at all output jacks except
the Tuner Out jack (#27).
3. PAD: This switch, when depressed,
attenuates the input signal by 15dB. If your
bass has active pickups, depress this
switch to better accommodate its output
signal.
4. GAIN: Use this control to adjust the
level of the input signal. When properly set,
the Peak LED (#5) will flash on strong signals. For the best signal to noise ratio set
the Gain control to the highest useable setting and adjust the Drive and Master controls (#8, 18) to obtain the desired output
level.
5. PEAK/MUTE LED: This LED illuminates
when the preamp signal approaches clipping. When the Mute switch (#2) is
engaged, this LED stays on as a visual
indicator that the Mute function is active.
6. BRIGHT: This switch, when depressed,
boosts the upper mid and high frequencies.
7. ULTRA LO: This switch, when depressed, provides emphasis to the low end
by boosting the low frequencies and cutting
the mid frequencies.
8. DRIVE: Use this control to adjust the
level of the distortion. In the fully counterclockwise position the preamp is in the
cleanest, traditional SVT condition. As the
control is rotated clockwise, the distortion
level is increased. The tone of the signal is
also changed to provide a smoother overdrive. The tone controls may have to be
readjusted to obtain the desired tone. The
Gain control (#4) and Pad (#3) interact with
the Drive control. For greater overdrive, the
Pad switch (#3) should be out and the
Drive control should be rotated fully clockwise. Use the Gain control (#4) to set the
amount of overdrive desired. The Peak
LED (#5) will remain illuminated when the
amplifier is used in this manner.
9. BASS: Use this control to adjust the low
frequency output level. This control provides 12dB of cut or boost at 40Hz.
10. MIDRANGE: Use this control to adjust
the mid frequency output level. This control
provides 15dB of cut or 12dB of boost at
the frequency selected by the Frequency
control (#11).
11. FREQUENCY: Use this control to
select the center frequency for the
Midrange control (#10). The center frequencies are 220Hz, 450Hz, 800Hz,
1.6kHz, and 3kHz.
12. TREBLE: Use this control to adjust the
high frequency output level. This control
provides 12dB of cut or boost at 4kHz.
13. GRAPHIC EQ: This switch, when
depressed, activates the Graphic EQ.
(When using a footswitch, #23, to control
the Graphic EQ, this switch must be
depressed.)
14. ULTRA HI: This switch, when
depressed, boosts the frequencies above
those affected by the Bright switch (#6).
15. GRAPHIC EQ : Use these controls to
adjust the amplitude of the signal at the frequency stated above each slider.
16. GRAPHIC EQ LEVEL: Use this control
to adjust the overall output level of the
Graphic EQ.
17. GRAPHIC EQ ACTIVE/PEAK LED:
This LED illuminates yellow when the EQ
section is active. This LED will flash when
the amplitude of the Graphic EQ signal
approaches clipping.
18. MASTER: Use this control to adjust
the overall output signal level.
19. POWER INDICATOR LED: This LED
illuminates green when the preamp is on.
20. POWER: Use this switch to turn the
preamp on (side of switch with the dot
depressed) and off (side of switch without
the dot depressed).
1 52 3 6 7 13144 8 9 10 11 12 18 201916 1715
5
SVP-PRO Bass Preamp
The Rear Panel
21. AC LINE IN: Firmly insert the female
end of the AC power cord into this socket.
The grounded power cord should only be
plugged into a grounded power outlet that
meets all applicable electrical codes and is
compatible with the voltage, power and frequency requirements stated on the rear
panel. Do not attempt to defeat the safe-
ty ground connection.
22. AC LINE SELECTOR: Use this switch
to match the unit to the AC line voltage.
23. FOOTSWITCH: Use this jack to connect a two-button footswitch to the preamp
for remote control of the Mute and Graphic
EQ. (Tip controls Mute, ring controls the
Graphic EQ.) The front panel switches
remain active when a footswitch is connected. The front panel Graphic EQ switch
(#13) must be depressed for the footswitch
to control the Graphic EQ.
24. PREAMP OUTS: Use these jacks to
connect the signal from the preamp to your
power amplifier, mixing console or house
PA system.
25. EFFECTS LOOP RETURN: Use this
jack to connect the signal from an external
effects processor to the preamp by means
of a shielded signal cable.
26. EFFECTS LOOP SEND: Use this jack
to connect the signal from the preamp to
the input of an external effects processor
by means of a shielded signal cable.
27. TUNER OUT: Use this jack to connect
the preamp to an external tuner. The signal
at this jack is a direct output from the instrument. This is the only signal which remains
active when the Mute switch (#2) is
depressed.
28. PRE/POST: Use this switch to determine whether the signal at the Transformer
Balanced Out jack (#29) is pre-EQ (switch
in the out position) or post-EQ (switch
depressed).
29.TRANSFORMER BALANCED OUT:
Use this XLR jack to connect the preamp to
an external power amplifier, mixing console
or house PA system. The signal at this jack
is pre- or post-EQ depending on the setting
of the Pre/Post switch (#28).
System Block Diagram
PREAMP
OUT
PREAMP
OUT
INPUT
BUFFER
BUFFER
TUNER
OUT
PEAK
LED
GAIN
BRIGHT
ULTRA
HI
-15dB PAD
DRIVE
MID
FREQUENCY
BASS TREBLE
EQ ON
GRAPHIC
EQ
ULTRA
LO
EFFECTS
SEND
EFFECTS
RETURN
MASTER
PRE/POST
TRANSFORMER
BALANCED
OUT
MUTE
LEVEL
GRAPHIC
EQ
MUTE
FOOTSWITCH
SWITCHING
CIRCUIT
MADE IN THE U.S.A. BY
SLM ELECTRONICS
1400 FERGUSON AVENUE
ST. LOUIS, MO 63133
AC LINE IN
115V 230V
21 22 23 24 25 26 27 28 29
MODEL #
SERIAL #
SVP PRO
FOOT
SWITCH
PREAMP OUT EFFECTS TUNER
RETURN SEND
TRANSFORMER BAL. OUT
OUT
PRE
POST
6
SVP-PRO Bass Preamp
Important Information About Tubes and Tube Products
A
BRIEF HISTORY OF THE TUBE:
In 1883, Edison discovered that electrons would flow from a suspended filament when enclosed in an evacuated lamp. Years later, in
1905, Fleming expanded on Edison's discovery and created the "Fleming Valve". Then, in 1907, Dr. Lee de Forest added a third component – the grid – to the "Fleming's Valve" and the vacuum tube was a fact of life. The door to electronic amplification was now open.
During World War II, data gleaned from their intensive research on the detectors used in radar systems led Bell Telephone Laboratories
to the invention of the transistor. This reliable little device gained quick support as the new component for amplification. The death of the
vacuum tube seemed imminent as designers, scientists, and engineers reveled in the idea of replacing large, fragile glass tubes with
these small, solid-state devices.
However, there were (and still are) many serious listeners who realized that the sound produced by a "transistor" amplifier is significantly
different from that produced by a tube amplifier with identical design specifications. They considered the sound produced by these new
solid-state devices to be hard, brittle, and lifeless. It was determined that solid-state devices produced a less musical set of harmonics
than tubes. When pushed past their limits, they tend to mute the tone and emphasize the distortion.
Tubes, on the other hand, produce a more musical set of harmonics, the intensity of which can be controlled by the player. This characteristic adds warmth and definition to the sound which has become the hallmark of tube amplifiers. When tubes are driven into clipping, the harmonic overtones can be both sweet and pleasing or intense and penetrating, depending on the musician’s musical taste
and playing technique.
Over the years, application engineers have designed a number of outstanding solid-state amplifiers that sound very, very good. Some
use special circuitry which enables them to simulate the distortion characteristics of a tube amplifier. However, the tube amplifier, still
held in the highest esteem by many musicians, offers a classic "vintage" sound in a contemporary market.
PREAMPLIFIER TUBE TYPES
AND USAGE:
The tubes used in preamplifiers (12AX7, 12AU7, 12AT7, etc.) amplify the signal from your instrument and shape the sound. They are
inherently microphonic (mechanically pick up and transmit external noises). Since these tubes are used in the critical first stages of a
tube preamplifier's circuitry, it is very important to use high-quality, low noise/low microphonic tubes for this application. Although tubes
of this quality may be difficult to find and typically cost more than "off-the-shelf" tubes, the improvement in performance is worth the
investment.
THE NATURE OF TUBES: WHY (AND WHEN) TO REPLACE THEM:
Tubes are made up of a number of fragile mechanical components that are vacuum-sealed in a glass envelope or bubble. The tube's
longevity is based on a number of factors which include how hard and often the equipment is played, vibration from the speakers, road
travel, repeated set up and tear down, etc.
If your preamplifier squeals, makes noise, loses gain, starts to hum, lacks "sensitivity", or feels as if it is working against you, the preamplifier tubes may need to be replaced. Remember to use only high quality, low microphonic tubes.
If you're on the road a lot, we recommend that you carry a set of replacement tubes.
SUR
VIVAL TIPS FOR TUBE PREAMPS:
To prolong tube life, observe these tips and recommendations:
• After using the preamplifier, allow sufficient time for it to properly cool down prior to moving it. A properly cooled preamplifier prolongs tube life due to the internal components being less susceptible to the damage caused by vibration.
• Allow the preamplifier to warm up to room temperature before turning it on. The heat generated by the tube elements can
crack a cold glass housing.
• Protect the preamplifier from dust and moisture. If liquid gets into the preamplifier proper, or if the preamplifier is dropped
or otherwise mechanically abused, have it checked out at an authorized service center before using it.
• Proper maintenance and cleaning in combination with routine checkups by your authorized service center will insure the
best performance and longest life from your preamplifier.
CAUTION: Tube replacement should be performed only by qualified service personnel who are familiar with the dangers of
hazardous voltages that are typically present in tube circuitry.
7
SVP-PRO Bass Preamp
Some Suggested Settings*
*A Note About The Graphic EQ:
The Graphic EQ can be used in two ways:
1) To fine tune your sound, make small adjustments at the
desired frequencies and leave the EQ on throughout the
entire session. (This is great for adapting to varying room
acoustics when going from club to club, etc.);
2) For a completely different sound, make larger adjustments
and only activate the EQ when you want a “second channel”
sound (such as during bass solos).
JAZZ:
FUNK:
ROCK:
COUNTRY:
ULTRA LO /
GAIN DRIVE BASS MIDRANGE FREQUENCY TREBLE
BRIGHT
ULTRA HI /
GRAPHIC EQ
IN
LO
OUT
PEAK / MUTE
ADJUST UNTIL PEAK LED FLASHES
GAIN DRIVE BASS MIDRANGE FREQUENCY TREBLE
BRT
ULTRA LO /
BRIGHT
IN IN
LO
OUT
PEAK / MUTE
ADJUST UNTIL PEAK LED FLASHES
GAIN DRIVE BASS MIDRANGE FREQUENCY TREBLE
BRT
ULTRA LO /
BRIGHT
LO
OUT
HI
OUT
EQ
ULTRA HI /
GRAPHIC EQ
HI
OUT
EQ
ULTRA HI /
GRAPHIC EQ
OUTOUT
HI
IN
PEAK / MUTE
ADJUST UNTIL PEAK LED FLASHES
GAIN DRIVE BASS MIDRANGE FREQUENCY TREBLE
BRT
ULTRA LO /
BRIGHT
IN
LO
OUT
PEAK / MUTE
ADJUST UNTIL PEAK LED FLASHES
BRT
OUT
EQ
ULTRA HI /
GRAPHIC EQ
OUT
HI
OUT
EQ
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 47-546-13 • 032603
Technical Specifications
TOTAL SYSTEM GAIN 76dB, @1kHz w/levels up, tones flat; -3dB @30Hz, 15kHz
TONE CONTROL RANGE
Bass: ±12dB @ 40Hz
Midrange: +12dB, -15dB @ Frequency selected (220, 450, 800, 1.6k or 3kHz)
Treble: ±12dB @ 4kHz
Ultra Low: +3dB @ 40Hz, -12dB @ 500Hz
Ultra High: +8dB @ 8kHz
Bright: +7dB @ 2kHz
GRAPHIC EQ RANGE ±12dB @ 40Hz, 90Hz, 180Hz, 300Hz, 500Hz, 1kHz, 2kHz, 4kHz, 10kHz
GRAPHIC EQ LEVEL +8dB, -10dB
SIGNAL TO NOISE RATIO 80dB typical
TUBE COMPLEMENT 12AX7 (4), 12AU7 (1)
POWER REQUIREMENTS
Domestic: 120VAC, 60Hz, 28VA
Export: 100/115VAC 50/60Hz, 28VA
230VAC, 50/60Hz, 28VA
SIZE AND WEIGHT 19”W x 1.75”H x 10”D; 9 lbs
SVP-PRO Bass Preamp
www.ampeg.com
Declaration Of Conformity
#36, Effective 01-01-2001
Manufacturer’s Name: SLM Electronics
Production Facility: 11880 Borman Drive, St. Louis, MO 63146, USA
Production Facility: 700 Hwy 202 W, Yellville, AR 72687, USA
Shipping Facility: 1400 Ferguson Ave., St. Louis, MO 63133, USA
Office Facility: 1400 Ferguson Ave., St. Louis, MO 63133, USA
Product Type: Audio Amplifier
Complies with the following Standards:
Safety: EN60065, E60065, C22.2, UL6500 and/or UL813
EMC: Directive 89/336/EEC, EN55103, EN55013, EN61000,
and/or FCC 47CFR 15B clA
Supplementary information provided by:
SLM Electronics - R & D Engineering
1901 Congressional Drive, St Louis, MO 63146, USA
Tel.: 314-569-0141, Fax: 314-569-0175
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