AM 320-01-808
48
10. WV 30 (Wersivoice)
Basically, the WV 30 board is a phase/frequency modu-
lator, which is responsible for two effects: the "Strings"
effect and the "Leslie" effect (simulating rotating speakers).
The modulation is produced by mixing differently delayed
audio signals together. The delay is generated by special
components, so-called bucket brigade devices. Bucket
brigade devices delay a certain audio signal proportionally
to a clock frequency.
The WV 30 employs three bucket brigade devices (block
diagram: BBD 1-3). Each bucket brigade belongs to a
voltage controlled oscillator (VCO 1-3). The VCOs are
modulated by two LFOs (low-frequency oscillators) with
three outputs each.
"Strings" effect: LFO 1 has a frequency of 0.6 Hz and
generates three triangle voltage signals, which are dis-
placed to each other by 1200. LFO 2 has a frequency of 6
Hz and generates three sine wave signals, which are also
displaced to each other by 120°.
Rotation (Leslie) effect: LFO 1 has a frequency of either
0.6 or 6 Hz (vibrato fast/slow), LFO 2 is off.
The Deep and Flat switches are effective on the audio
path. Deep being a feedback process (amplification of
the respective effect) and Flat being a partial "short circuit"
of the bucket brigades (smoothing the respective effect) -
The elements of the block diagram can easily be seen in the
schematic diagram:
Via IC 2, the input signal reaches the bucket brigades (IC 4,
5,6). The corresponding VCOs consist of IC 7-9 and Q 3-8.
The LFO 1 consists of IC 11, 12, 13: LFO 2 consists of IC
10, 14.
The remaining three OPAMPs in IC 2 form the output filter
amplifier.
IC 3 is the switch to determine the feedback for the
Deep/Flat effects.
IC 1 is responsible for the TT 1/CMOS level conversion.
To Next Page
Loading...
