SEQUENCER AND DRUM MODIFICATIONS
The circuit below will allow the WP-20 to be con-
trolled by a sequencer. First, mount two jacks in a
convenient place near the Trigger Switch (S3 on figure
2), The gate output of the sequencer will be used to
trigger the A.D. Generator in the WP-20 through a
2N3904 transistor. The Trigger Switch is a convenient
place to mount the transistor. Solder the collector to
the terminal of S3 identified as Point B. Solder the
emitter to the other terminal. Connect a l0K resistor
from the base of the transistor directly to the 'hot'
terminal of one of the newly installed jacks. Provision
must also be made to control the VCO in the WP-20 with
the sequencer control voltage. Wire a l00K resistor
from the 'hot' terminal of the other jack to pin 1 of 1C3
as shown above. The sequencer mod is now complete.
The WP-20 may be wired to function as a drum
synthesizer. Mount a jack in the side of the case near
Trigger Switch (S3). The 'hot' lead of the jack should be
connected to the 'Point B' side of S3 Wire the ground
terminal of the jack to the other side of S3 Connect a
SPST switch through shielded cable and a plug to the
jack. This external switch should be mounted so that it
can be easily struck with your hand or a drum stick.
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