021402
Vocal Zapper 11
(+) input of IC1, thus producing cancellation of common-mode information (i.e.
anything in the center channel above approximately 160 Hz). Note that in the
zap mode, the overall output level may seem slightly lower since the center
channel information is missing. S1b compensates for this effect by slightly
reducing the gain of IC1 in the normal mode. R12 allows the user to adjust the
Vocal Zapper for the maximum amount of lead vocal cancellation. IC1:B's
output couples back into the stereo system through R1 and R2.
IC1:A is a simple mic preamp that accommodates a variety of different micro-
phones, and mixes the microphone signal into IC1:B to replace the lead vocal
with your voice. The mic output goes directly into the (+) input of IC1:A, whose
gain is set by R11. IC1:A's output then couples through C6 and R4 into the (-)
input of IC1. Power for both opamps is provided by a + 9v (bipolar) transistor
radio battery supply. The Vocal Zapper is intended for use with stereo systems
having TAPE OUT and TAPE MON jacks (see INSTALLATION).
IN CASE OF DIFFICULTY
Recheck the wiring according to the instructions given previously in this
manual. Also, make sure the batteries are fresh and functional. Pay special
attention to the orientation of the ICs and to the solder connections. Many kits
are returned for repair having nothing more wrong with them than a bad solder
connection or two. Finally, check for solder bridges, wire bits, or other foreign
matter which may be lodged across conductors on the circuit board.
Should you be unable to determine the source of the difficulty, a repair service
is available. BEFORE sending the unit back, write us for return instructions and
authorization to the addresses on the back cover of this manual or email to
[email protected]. Give as full a description of the malfunction as possible; in
many cases your problem may be diagnosed by mail. If no diagnosis can be
made, you will be supplied with a repair address and shipping instructions.
