A C O U S T I C B L E N D E R S Y S T E M
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APPENDIX III: THE FISHMAN SMART SWITCH
If your instrument has an active pickup/preamp and you are
going to route electret microphone and pickup signals
through a single stereo cable, you may need to install a
SMART SWITCH for the system to operate.
WHAT IS A SMART SWITCH?
The SMART SWITCH is a voltage sensing electronic switch.
A SMART SWITCH must be installed with certain pickup/pre-
amp/microphone configurations due to the physical limita-
tions of the Stereo (TRS) jack used on the instrument.
WHY DO I NEED A SMART SWITCH?
Most instrument mounted preamps have no on-off switch. Instead, they rely on a
"switching" stereo jack that turns the preamp on when a 1/4" plug is inserted.
The actual switching is performed by the plug: it shorts the negative battery wire
(RING connection) to ground. Similar in function to the input jack on a "stomp
box" pedal, the switching jack can extend battery life since the preamp is turned
off with the plug removed. The standard wiring configuration is as follows:
TIP= Pickup Signal carrier
RING= Negative Battery wire
SLEEVE= ground
Adding the Fishman/Crown GLM-200 microphone to a switching jack configura-
tion creates an electronic version of musical chairs in which the microphone sig-
nal and negative battery wire are both vying for the same RING terminal on the
stereo jack. Attempting to connect both the microphone and Battery wire to the
RING terminal will ground out the microphone.
WHAT DOES THE SMART SWITCH DO?
The Smart Switch takes over the preamp power switching duty and frees up the
RING terminal on the output jack for the microphone signal. The Smart switch
takes its cue by electronically sensing phantom power, sent from the Blender and
in turn switching on the preamp.
In cases where the mic is not needed, the Smart Switch will know to turn on the
preamp with a mono phone plug inserted.
Pretty smart, eh?
WHO NEEDS A SMART SWITCH?
The following Fishman pickup/preamp systems will require a SMART SWITCH to
be installed in conjunction with the Fishman/Crown GLM-200 Microphone:
Acoustic MATRIX Natural
Acoustic MATRIX Hot
Acoustic MATRIX Professional
AGP-2 and ABGP Onboard
Guitar Preamps
Other manufacturers’ preamps may also require a SMART SWITCH. Contact the
Fishman’s PRODUCT INFORMATION LINE at 978-988-9665 for assistance.
NOTE: The SMART SWITCH is NOT required when using a Fishman POWER-
JACK endpin preamp in conjunction with the Fishman/Crown GLM 200 mic.
