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F
P
I S H M A N
O W E R B R I D G E
Continued from other side
Magnetic and piezo pickups operate on different electrical platforms. Magnetics
are "inductors" and piezos are "capacitive" devices.
The solution is to
electronically isolate or "buffer" the two signals with the Fishman Powerchip™.
Passive Setup
Stereo Output Jack
(Tip/Ring/Sleeve)
Powerbridge™ Signal
Pure Magnetic Signal
(Ring)
(Tip)
Active
D.I.
PA / Recording Console
Electric Guitar Amp
• Active Setup - Powerchip
With our onboard Powerchip, you can mix and combine both the Powerbridge™
and magnetic pickups (on the guitar) and plug right into a single channel guitar
amplifier. You can also instantly split signals by simply changing to a stereo
cable or stereo "Y" cable.
See the Powerbridge™ Users Guide for the Powerchip™ description.
Active Setup
Powerchip™
Mono Instrument Cable
™
P
I
I C K U P
N S T A L L A T I O N
Bridge Installation
• Installation of the Fishman Powerbridge™ should be performed only by a
qualified repairman. Fishman Transducers will not be responsible for any
damages that may result from improper installation.
Although several different styles of tune-o-matic bridges exist, the Fishman tune-
o-matic Powerbridge™ Pickup will replace many original equipment bridges with
little or no modification to the instrument. The most common tune-o-matics are
the Gibson Nashville and ABR-1 models.
• How to determine which bridge you are
replacing
A Nashville bridge is easy to visually identify by the .472" (12 mm) diameter
bushings that are press-fit into the guitar's top.
An ABR-1 bridge will always have threaded posts that are fastened directly into
the top (or ebony base, in the case of archtop) of the instrument. An ABR-1 also
has a single retaining wire that spans the length of the bridge and holds the
intonation screws in place.
• Installation Procedure
1. Remove the existing bridge. Identify what style tune-o-matic it is. (see above)
2. If the old bridge is "Nashville" style, no fitting will be necessary. If the old
bridge is the "ABR-1" style, we recommend that you replace the height
adjusters with the ones included in the Powerbridge™ kit. Fill the old holes
and use the included drilling template to locate new holes for the height-
adjuster bushings.
3. Position the bridge so that the wire exits on the treble side.
4. Wire Routing - If the guitar has mounting bezels for the magnetic pickups
(like a Les Paul), then you can easily route the wire through the lead pickup
cavity. Remove the bezel and make a notch in the plastic (using a round
jeweler's file) in the gap between the metal pickup housing and the screw
hole closest to the high E string saddle. Then route the wire through the into
the control cavity.
Under-side of Humbucking pickup
For hollow body instruments (like ES-335), you may also run the
Powerbridge™ wire through the treble-side f-hole.
For solid body instruments (like many SG's) with no mounting bezel for the
mags, you can either run the wire under the pickguard or drill a hole directly
under the bridge into the control cavity.
Wiring Instructions
G
U I D E
• Preliminary Notes
To prevent 60 Hz hum, the entire Powerbridge™ Pickup signal path should be fully shielded. The control cavity, jack cavity, and any non-conductive
surface to which the controls are mounted (such as a plastic pickguard) must be shielded with adhesive-backed foil or conductive paint. The
shielded cavities should then be grounded.
For complete hum prevention, the included stereo jack should also be shielded. To do this, we've included a piece of shielding foil. Note that one
side is insulated. After you have soldered the wires to the jack, roll the foil into a tube so that the insulation is on the INSIDE and surround the
stereo jack with the tube. Connect the foil side of the tube to ground by soldering it to the shielding of the Powerbridge™ Pickup wire or to a jumper
that is connected to any ground.
If your instrument has active magnetic pickups (requiring an onboard battery), you will need a special 9 Pin Switching Jack (Fishman Part Number
ACC-PBR-9PJ), available through your Fishman dealer.
• Wiring Options
There are several different ways to wire the
Tune-o-matic Powerbridge™ Pickup - choose the
option that best suits your needs ...
Powerbridge™ & Magnetic Pickups
wired directly to a Stereo Jack
1. Connect the Powerbridge™ signal wire directly to
the Ring terminal on the supplied stereo jack.
2. Connect the Powerbridge™ and magnetic grounds
to the Sleeve terminal.
3. Connect the magnetic signal wire to the Tip
terminal.
Passive Volume
for the Powerbridge™
This circuit that is easily assembled from "stock" guitar
FILE HERE
pots and components available at any electronics
parts retailer.
You will need:
• 250 k (or 300 k for long shaft Les Paul
pot
• 330 k resistor
• 820 pF capacitor
• 1500 pF capacitor
This network will attenuate the Powerbridge™ so that
it better matches levels between magnetic and piezo
pickups. You can expect a 14 dB (nominal) decrease
in Powerbridge™ output with this circuit.
NOTE: Optional 3-Way Selector Switch - If
desired, a single pole, double throw (spdt) 3-way switch can
also be added for piezo/magnetic pickup selection. Use a
switch with an ON-OFF-ON orientation (no, this is not a
misprint)
NOTE: Active Onboard Blending
A Fishman Powerchip™ (not included) must be installed if you
wish to blend/mix piezo and magnetic signals onboard the
instrument.
FISHMAN TRANSDUCERS
340-D Fordham Road Wilmington MA 01887 USA
Phone 978-988-9199 • Fax 978-988-0770
www.fishman.com
Magnetic
Signal
Magnetic
Volume
Sleeve
Tip
Stereo Jack
Direct Wiring
®
) audio taper
250K - 300K
Audio T aper Pot
820 pF
330 K
1500 pF
1500 pF
Magnetic Signal
®
Passive Volume
®
Powerbridge™
Optional 3-Way
Selector Switch
Both
Mag
Piezo
Ring
ON
OFF
ON
Optional 3-Way
Selector Switch
Both
Mag
Piezo
Sleeve
Ring
O
O
O
F
Tip
N
N
F
Stereo
Output
Jack
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