Ampeg Bass heads SVPBSP User Manual

							2Important 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 preamp, yourself and others.
•The preamp 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 preamp ONLYto a properly grounded AC outlet of the proper voltage for your preamp. 
•Avoid sudden temperature extremes, rain and moisture. Also, avoid sudden and intense impact. (If the pre-
amp has been subjected to any of the preceding abuses, have it looked at by an authorized service center.) 
•Unplug the preamp before cleaning it. NEVER spray liquid cleaners onto the preamp. Wipe it with a slight-
ly dampened, lint-free cloth to remove dirt and film.
•Don’t use the preamp if it has sustained damage to the chassis, controls, or power cord. Refer the unit to
an authorized service center for inspection.
•When using tall or stacked speaker cabinets, use them ONLYon a level surface. NEVERset tall or stacked
cabinets on a surface with more than a five degree incline since tipping or falling could occur, possibly caus-
ing serious injuries.
•NOTE: 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 is 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.
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
UNIT AND PREVENT ACCIDENTAL 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 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 UNIT IS
OPERATED AT HIGH  VOLUME.
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=
=
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
TABLEOFCONTENTS
Important Safeguards and Precautions  . . . . . . . . . . . . . . .2
Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Features  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
The Front Panel Controls and Their Use  . . . . . . . . . . . . . .4 
The Rear Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Some Suggested Settings  . . . . . . . . . . . . . . . . . . . . . . . . .6
Changing the Tubes  . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
System Block Diagram  . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Technical Specifications  . . . . . . . . . . . . . . . . . . .back cover
SVP-BSP Bass Preamp 
						

							3
An Introduction to your new Ampeg SVP-BSP Bass Preamp
When a living legend asks you to design a bass preamp, you don’t cut corners – you deliver.
So when bassist extraordinaire Billy Sheehan turned to Ampeg for his preamp, we listened to his
needs, found out his wants, and made real his dreams: behold, the SVP-BSP bass preamp! A
unique piece of gear for the discriminating bassist, with two separate channels – clean and over-
drive – and the ability to combine the two channels into a third, at the touch of a button. We even
gave each channel its own effects loop and level-controllable balanced XLR output jack. 
In designing the SVP-BSP, we were careful not to lose the harmonically rich sound of Ampeg’s
SVT bass amps. This dynamic  preamp still delivers unsurpassed quality, reliability and tonal flex-
ibility, and offers the classic vibrancy of tubes as well as many new features.
All of the features and controls of your SVP-BSP are covered in detail within the pages of this
owner’s guide. We recommend going over them before you use the preamp.
And a hearty “thank you” from Ampeg – and Billy!
Features
In the world of high performance bass amps, Ampeg’s SVT amplifiers stand alone. Keeping
with true Ampeg tradition, the SVP-BSP Bass Preamp offers you more performance and flexibil-
ity 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:Perfect for basses with active electronics or very “hot” pickups (page 4)
•MUTE SWITCH:Cuts the sound from the preamp, letting you tune your bass in pri-
vate (page 4)
•TWO SEPARATE CHANNELS:Choose between the clean channel, the overdrive
channel, or both, for a wide variety of sounds (page 4, page 6)
•COMPRESSOR SWITCH:Evens out your volume by governing the dynamic range
of the preamp (page 4)
•ULTRA LOW, ULTRA HIGH AND GAIN BOOST SWITCHES:For additional tonal
flexibility – lets you further tweak your sound (page 4, page 6)
•VARIABLE MIDRANGE SELECTOR:Custom select your center frequency point to
get just the right midrange voice (page 4, page 6)
•GATE SWITCH:Keeps things quiet in between bass riffs (page 4)
•FOOTSWITCH CONTROL: Use a two-button footswitch (like Ampeg’s AFP-2) to
control channel selection and muting (page 5)
• TWO EFFECTS LOOPS:Lets you add your effects to either channel (page 5)
• TWO PREAMP OUTPUTS:Each channel has its own 1/4” jack to send its signal to
separate amps/speakers if desired (page 5)
• TWO TRANSFORMER-BALANCED XLR OUTPUTS:Each channel has its own
XLR jack (with level control) to send a balanced signal from the preamp (page 5) 
SVP-BSP Bass Preamp 
						

							4
SVP-BSP Bass Preamp
The Front Panel Controls and Their Use
PAD /
 MUTE
GAIN BASS MIDFREQUENCY VOLUME MASTERTREBLE MID BASS GAIN TREBLE VOLUME INPUTPOWER
CLEANOVERDRIVE
-6dB
MUTECH. SELECT
COMBINE
PEAKCLEANOD
15 236 4789
PULL GATE PULL BOOST PULL ULTRA PULL ULTRA PULL COMP
1011121314161521 17181920
1. INPUT: If we have to tell you what to do
here, we’re both in trouble! (Just remem-
ber to use a shielded cable, okay?) 
2. MUTE: Push this button and the pre-
amp’s output is cut off (no signal gets
through to your amp). The Tuner Out jack
(#35) isn’t affected by this switch, so you
can tune in private. If a footswitch is
connnected (#23), this switch still remains
active.
3. PAD: If your bass has active electronics
or “hot” pickups (lots of Peak LED with a
low Gain setting – see #4 and 5), you’ll
need this switch. Pressing the switch in
reduces the signal level going into the pre-
amp by 6dB, allowing you more room to
adjust the Gain controls (#4, 10).
CLEAN CHANNEL:
4. GAIN:This control, along with the Pad
switch (#3), adjusts the level of the signal
going into the clean channel. For the best
signal to noise ratio, set this control so
that the Peak LED (#5) flashes during
your loudest passages.
5. PEAK LED: This LED flashes when the
signal level into the preamp nears clip-
ping. When the Mute switch (#2) is
engaged, this LED stays lit.
6. BASS:The low frequency control for
the clean channel, with a 20dB range at
40Hz. Pull the knob out to add a boost to
the lowest frequencies.
7. MID: The midrange control for the clean
channel, with a 21dB range at 300Hz.8. TREBLE: The high frequency control
for the clean channel, with an 18dB range
at 10kHz. Pull the knob out to boost the
highest frequencies.
9. VOLUME:This controls the output level
for the clean channel.
OVERDRIVE CHANNEL:
10. GAIN:This control, along with the Pad
switch (#3), adjusts the level of the signal
going into the overdrive channel. Pull the
knob out to boost the gain (allowing more
distortion). With the boost on, the preamp
automatically adjusts the frequency
response to compensate for the added
gain.
11. BASS:The low frequency control for
the overdrive channel, with 12dB of cut or
boost at 100Hz. 
12. MID:The midrange control for the
overdrive channel, with 5dB of cut or 20dB
of boost at the center frequency as cho-
sen by the Frequency control (#13). 
13. FREQUENCY:Allows you to select
the center frequency for the Midrange
control (#12), giving you a wide range of
choices for the “voice” of the Midrange.
The center frequencies range from 300Hz
at the “0” position to 2kHz at the “10 “
position.
14. TREBLE: The high frequency control
for the overdrive channel, with 12dB cut or
boost at 7kHz.
15. VOLUME:This controls the output
level for the overdrive channel. Pull theknob out to engage the gate circuit – this
activates a fixed-threshold noise gate,
which virtually turns the channel off when
there’s no input signal. (This keeps things
quiet when your rig is on but you’re not
actually playing.)
16. MASTER:This controls the overall
output volume level of the preamp, keep-
ing the same balance between channels
as set by their volume controls.  
17. CHANNEL SELECT: This switch
selects the clean channel when out and
the overdrive channel when in. When a
footswitch (#23) is used, this switch is dis-
abled.
18. COMBINE:This switch does exactly
what it says: it combines the clean chan-
nel with the overdrive channel when the
overdrive channel is selected. 
NOTE:In order to hear a combination of
the two channels, the Channel Select
switch (#17) must be in the OVERDRIVE
(“in”) position. Otherwise, only the clean
channel will be heard.
19. CLEAN LED:This LED indicator
glows green when the Clean channel is
active.
20. OVERDRIVE LED:This LED indicator
glows red when the Overdrive channel is
active.
21. POWER: This switch turns the pre-
amp on (towards the white mark) and off. 
						

							5
SVP-BSP Bass Preamp
The Rear Panel
OVERDRIVE MIX RETURN SEND RETURN SEND
PREAMP OUTPUT
OVERDRIVECLEAN/CLEAN
LEVEL LEVELPRE
POST2440A
SVP-BSP MODEL
SERIAL #MADE IN THE U.S.A. BY
SLM ELECTRONICS
1400 FERGUSON AVENUE
ST. LOUIS, MO 63133AC LINE
  IN
2223242526272829303233353134
FOOT
SWITCHCLEANTRANSFORMER BALANCED OUTPUTOVERDRIVEEFFECTS LOOPTUNER
OUT
TIP = CHANNEL
RING = MUTE
22. AC LINE IN: Connect the power cord
here, making sure it is fully seated in the
socket. Plug the male end of the cord into
a grounded AC outlet. DO NOT DEFEAT
THE GROUND PRONG OF THE AC
PLUG!
23. FOOTSWITCH: Connect a two-button
footswitch here for control of muting and
channel selection: tip = channel select,
ring = mute, sleeve = ground. 
NOTE:With a footswitch attached, the
channel select footswitch overrides the
front panel channel switch; however, the
front panel mute switch remains active.
24, 25. PREAMP OUTPUTS: Connect
these jacks to your power amp(s). If only
the Clean/Mix output (#25) is used, all out-
puts (clean, overdrive, and combined)
appear at this jack. When a plug is insert-ed into the Overdrive output (#24), the
clean and overdrive outputs appear at
their respective jacks.
26 – 29. EFFECTS LOOPS: Each chan-
nel of the preamp has its own effects loop
for connecting external effects. Connect
the Send jack (#27 or 29, depending on
the channel) to the input of the device,
then connect the output of the device to
the Return jack (#26 or 28).
30, 33. BALANCED OUTPUT LEVELS:
These controls adjust the levels of the sig-
nals at the Balanced Output jacks: #30 is
for Overdrive, #33 is for Clean. 
31, 34. BALANCED OUTPUT JACKS:
These XLR-type jacks can be used to
feed an external power amplifier, mixing
console, or house PA system: #31 is for
Overdrive, #34 is for Clean. The overdriveoutput is post volume and pre master. The
clean channel’s output is selected via the
pre/post switch (#32).
32. PRE/POST:In the post position
(switch out), the signal is post volume, pre
master. In the pre position (switch in), the
signal is taken directly from the preamp
tube. It’s like having a built-in tube direct
box in the preamp.
35. TUNER OUT: This jack lets you send
a direct signal from your bass to your
tuner, regardless of the settings of the pre-
amp. Even with the Mute on, the output at
this jack is the same as if you connected
directly from your bass.  
						

							6
Some Suggested Settings
SVP-BSP Bass Preamp
GAIN BASS MIDFREQUENCY VOLUME MASTERTREBLE MID BASS GAIN TREBLE LEVEL
GAIN BASS MIDFREQUENCY VOLUME MASTERTREBLE MID BASS GAIN TREBLE LEVEL
GAIN BASS MIDFREQUENCY VOLUME MASTERTREBLE MID BASS GAIN TREBLE LEVEL
GAIN BASS MIDFREQUENCY VOLUME MASTERTREBLE MID BASS GAIN TREBLE LEVEL
GAIN BASS MIDFREQUENCY VOLUME MASTERTREBLE MID BASS GAIN TREBLE LEVEL
Smooth Dirty SVT
Slappin Metal
Edge
Mud & Fuzz
Big Bass
*As Needed
Dirty SVT
CLEANOVERDRIVE
CLEANOVERDRIVE
CLEANOVERDRIVE
CLEANOVERDRIVE
CLEANOVERDRIVE
PULL OUTPULL OUT
PULL OUTPULL OUTPULL OUTPULL OUTBUTTON OU
BUTTON IN BUTTON IN
BUTTON IN
BUTTON IN
BUTTON IN
BUTTON IN
BUTTON OU
PULL OUT
PULL OUTPULL OUT
PULL OUT
CH. SELECT
COMBINE
PEAKPULL GATE PULL BOOST PULL ULTRA PULL ULTRA PULL COMP
CH. SELECT
COMBINE
PEAKPULL GATE PULL BOOST PULL ULTRA PULL ULTRA PULL COMP
CH. SELECT
COMBINE
PEAKPULL GATE PULL BOOST PULL ULTRA PULL ULTRA PULL COMP
CH. SELECT
COMBINE
PEAKPULL GATE PULL BOOST PULL ULTRA PULL ULTRA PULL COMP
CH. SELECT
COMBINE
PEAKPULL GATE PULL BOOST PULL ULTRA PULL ULTRA PULL COMP 
						

							7
SVP-BSP Bass Preamp
Changing the Tube
Tube wear is in direct proportion to how often you use the preamp. When the tube wears out, the preamp may squeal,
get noisy, lose gain and sensitivity, or just quit working. To get to the tube in the SVP-BSP, the top must be removed. This
should be left to a qualified service person.
System Block Diagram
INPUTBUFFER
TUNER
OUT
-6dB PAD
PRE
POST
MUTEULTRA
LOW
ULTRA
HIGHON
BOOST
BASSMID
TREBLEGAIN
VOLUME
LEVEL
MASTERCLEAN/
MIX BAL.
OUT
CLEAN/
MIX TUBE
GAINTONES
COMPRESSSOR
GATE
EFFECTS
LOOP
OVER-
DRIVE
FOOT
SWITCH
CHANNEL
SELECT
GAINMIDVOLUMEBASS TREBLE
FREQ.
EFFECTS
LOOP
COMBINE
LEDS
SWITCHING LOGIC
LEVELOVER-
DRIVE
BAL. OUT 
						

							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 47-546-51 • 01-99
Technical Specifications
TOTAL SYSTEM GAIN 
Clean Channel22dB, @1kHz w/levels up, tones flat
Overdrive Channel80dB, @1kHz w/levels up, tones flat 
TONE CONTROL RANGE 
Clean Channel
Bass:20dB range @ 40Hz
Midrange:21dB range @ 300Hz
Treble:18dB range @ 10kHz
Ultra Low:+5dB @ 30Hz 
Ultra High:+7dB @ 15kHz
Overdrive Channel
Bass:±12dB @ 100Hz
Midrange:+20dB, -5dB @ 300 – 2kHz
Treble:±12dB @ 7kHz
SIGNAL TO NOISE RATIO80dB typical, Clean channel
TUBE COMPLEMENT12AX7 (1) 
POWER REQUIREMENTS
Domestic:120VAC, 60Hz, 15VA
Export:100/120VAC 50/60Hz, 15VA
220 – 240VAC, 50/60Hz, 15VA
SIZE AND WEIGHT19”W x 1.75”H x 10”D; 10 lbs
SVP-BSP Bass Preamp
www.ampeg.com