Wednesday 19 February 2014

Serge Paperface Acid

A second Morley Serge video.
Mainly exploring the Analog Shift Register (ASR) and the triple wave shaper



Lovely acid mixed with dripping water.

Ken S. says that most of the PCBs date from around 1974/75.
...predating the rise of the Roland 303 by nearly a decade.

The 1973 serge filter is a 2 pole, 12dB LP & HP.
(With 6dB slopes on the BP).
Most of the acid sounds are care of the 12db High Pass.

The modules used are:
Serge '73 Oscillators x 3
10 stage sequencer
programmer x 2
Noise source
Negative Slew x 2
Envelope Generator
Send & receive
Mixer
Filter '73 x 3
Analog Shift Register (ASR).
Triple wave shaper (TWS).

The basic patch:
Patch a Neg Slew to cycle & use it to clock a Programmer Sequencer.

A CV from channel 1 of the programmer is fed into the ASR.
The ASR is clocked by the same Negative Slew.

The ASR produces 3 CVs which control the pitch of 3 VCOs.

VCO 1 (saw) ---> triple wave shaper -----> filter ----> BP out ---> mixer.
TWS is modulated by a 2nd Neg Slew, & the filter with some pink noise.

VCO 2 (saw)  ----> filter ----> LP ---Mixer
The filter is further modulated with Cv from the ASR.

VCO 3 (sine) ----> Filter -----HP out ---> mixer
The filter is modulated with Cv from a noise module & the Envelope Generator.

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