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Modular step sequencer of the "mee too" type
quad VCO
dual VCF
dual VCA
power supply
front panel
bigger image (137K)
backside small (48k) and big (104k)

This is analog sequencer having 3 rows of 8 knobs. Mode switch determines step count. It can be 8-steps with 3 channels, 16-steps with 2 channels, but seccond channel repeats twice in each cycle (e.g. step 9 outputs the same voltage as step 1), or 24 steps with only one output. Not used outputs serve as multiples of working channels. Sequencer can be started/stopped manually via start/stop buttons or external triggers. There's also gate signal that can be used instead of start/stop triggers.

Panel controlls upper row from left to right:
TEMPO knob:
controlls sequence speed together with range SLOW/FAST switch
STEP button:
advances active sequence position by 1
PW knob:
controlls duty cycle of common gate output
CV 1 & 2 knobs:
sequence speed modulation attenuators
GATE/TRIG switch:
determines mode of operation. In TRIG mode sequence is started and stopped via external triggers or buttons push, in TRIG mode sequence is running as long there's 5V at START input, or START button is pressed
START & STOP buttons:
start and stop the sequence. In GATE mode only START button/input is working
8/16/24 switch:
determines sequence length and channel count - 3 channels with 8 steps, or 2 channels with 16 steps while 2nd channel repeats every 8 steps, or 1 channel of 24 steps
RESET button:
resets sequence to step one.
remaining rows:
POTS 1-24:
knobs to set voltages at each step of the sequence. Row of smaller holes is for bi-color LEDs
OUTs & INs outputs:
voltage outputs of each channel, clock input, gates and common gate output, CV inputs, start/stop/reset control.

Schematics to be released when all bugs are fixed. Well, that statement was here for a looong time, 4 years actually. The bugs were fixed, but they have to be drawn into schematics. First, I'm too lazy to do that, second, I can't remember all changes that I made. Too bad. And I still have 3 empty PCBs for that beast. It would be nice to make them again someday.


early front panel (47k) and in higher resolution (52k)
backside at early stage (61k) and in higher resolution (91k)
empty sequencer PCB (76k) and in higher resolution (87k)

MIDI boards Modular synth Polysynth DSP Links history
© 2008 Roman Sowa
Last revised July 12, 2008