Sadowsky BP4F Installation Manual

INSTALLATION MANUAL
BP 4 F ONBOARD BASS PREAMP ( 4 -KNOB SYSTEM)
Master Volume / Balance / Vintage Tone Control (P/P) / Treble und Bass (Tandem)
The Sadowsky® Onboard Bass Preamp 4-Knob System can be used
to upgrade almost any bass guitar with passive pickups. The sys-
tem is pre-wired with all necessary components, including the out-
put jack, and requires no soldering for installation. The set includes
the famous Sadowsky preamp with volume and balance controls,
controls for the passive Vintage Tone Control (VTC) and a tandem
potentiometer for active EQ control with bass and treble boost. The
push/pull function of the VTC pot allows the bass to be switched
between active and passive mode. VTC works in both modes.
The wire lengths between the potentiometers are designed to fit
any bass with 4 controls plus an output jack. The potentiometers
can be mounted on control plates or in various arrangements from
the electronics compartment through holes in the body. For J-style
basses with a 4-hole metal control plate, we recommend the BP4K
Sadowsky On board Preamp Assembly, which comes pre-installed
on a control pate.
Control functions
• Volume control: fully right = max. volume
• Balance control: switches between the two pickups (end positions)
or mixes the signal from both pickups (intermediate positions),
middle position = 50/50 mix
• Bass / Treble: only boost available, fully left = neutral position (no
boost), fully right = 18 dB boost at 40 Hz / 4 kHz
• Vintage Tone Control (VTC): passive treble cut (works in passive
and active mode), fully right = no treble cut
• Push/Pull switch on VTC control: switches between passive mode
(preamp in bypass) and active mode
Note: Switching to passive does not turn off the battery. The bat-
tery is activated any time a cable is plugged into the output jack.
Remove the cable during long breaks and when not using the bass.
Specifications
• Frequency response ...................................................... 5 Hz - 50 kHz
• Bass control ................................................... + 18 dB Boost at 40 Hz
• Treble control ................................................. + 18 dB Boost at 4 kHz
• Total Harmonic Distortion (THD) ................................ 0,18% at 1 kHz
• Power source .............................................................. one 9 V battery
• Current draw ................................................................................ 9 mA
• Battery life ................................................................. up to 870 hours*
• Input impedance .................................................................... 1 MOhm
• Output impedance ................................................................... 1 kOhm
* Note: The battery drains as soon as a cable is plugged into the output
jack. Switching to bypass does not extend battery life. With normal
use, you can expect a battery life of around six months.
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Instrument requirements
• The preamp is designed for two passive pickups and is not compa-
tible with active pickups that require anything other than a 250K or
500K volume or balance pot.
• The instrument must have holes for four potentiometers and an out-
put jack, and there must be space in the electronics compartment
of the instrument for the potentiometers, the electronics board and
a 9 V battery.
The length of the potentiometer thread is 9 mm and the diameter is
10 mm. Please consider this when installing the pots through the
body wood. It may be necessary to ream the holes a little larger. You
can get a reamer at any hardware store or take your instrument to
an experienced technician.
• The electronics compartment should be shielded (shielding paint,
copper foil) to shield the preamplifier from outside interference.
The kit includes
• Pre-wired preamplifier circuit with PCB, potentiometers, battery clip
and output jack
• Instructions/circuit diagram
• All required potentiometer knobs
• Nuts and washers for mounting the potentiometers
• Allen wrench for attaching the knobs
Tools required
• Screwdriver to access the electronics compartment / remove the
control panel
• Small screwdriver for the terminal screws on the balance pot
• Socket wrench or spanner for loosening/tightening the nuts (12 mm
and 13 mm for kit + appropriate size for old potentiometers)
• Possibly a soldering iron for unsoldering old components
Installation
No soldering is required to install the preamplifier kit. However,
soldering may be required to remove the old electronics. All poten-
tiometers are fitted with keyed connectors to prevent incorrect
connection.
• Remove the old potentiometers and output jack from your instru-
ment. If you need to keep the original output jack, it must be a stereo
jack with three contacts (TRS), because the ring contact is used to
close the circuit for the battery.
• Identify and mark the „hot" and ground wires from the pickups and
the string/bridge ground wire.
• When unsoldering the wires from the old components, make sure to
leave a stripped and tinned piece of bare wire at the end that can be
inserted into the screw terminals on the balance pot.
Note for humbucker pickups with serial/parallel switching: If you
have additional toggle switches on your instrument, leave all wires
connected to these switches and use the wires running from the
switch to the volume or balance control as „hot" wires. Study the
wiring of your pickups or ask an experienced technician for advice.
• Check that there is sufficient space in the electronics compartment
for the new preamplifier electronics and a 9 V block battery. If there
is no room for the battery, you will need a technician to install a
separate battery compartment.
• If the compartment is not already shielded, you should shield it now
(shielding paint or copper foil).
• Check that the four holes for the pots of the new preamplifier kit are
suitable and test fit the pots to check the diameter. If necessary, care-
fully enlarge the holes with a reamer. Check that the potentiometer
threads extend far enough through the wood to install a washer and
a nut.
• Insert the potentiometers with a lock washer through the holes and
from the top put a flat washer and a nut on them. Hand-tighten for now.
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