[sdiy] DOTCOM Analog Sequencer.. next project startup..

Jean-Pierre Desrochers jpdesroc at oricom.ca
Fri Jul 24 15:52:33 CEST 2020

The need to be able to change any CV 'on the fly' when playing a sequence is
What I forgot to say is whether pots or encoders are used I need to be able
to change each step durations on each columns.

The possible sequences would be:
32/1    (32 monophonic notes on one row, fixed step duration)
16/2    (16 monophonic notes on one row, adjustable step duration for each
8/3      (8 trio of notes on 3 rows, adjustable step duration for each note

And also play forward/backward or even randomly the sequence.

Since rotary encoders have 3 to 4 data wires each the multiplexing of each
one after the other will be a challenge compared to standard pots but would
give the ability to achieve large CV span.
96 notes span would be nice on each CV controllers !
I'm hesitating to use a row of switches with only one encoder Instead of
multiple encoders...



I'm starting to think about my next DOTCOM analog module:
a 16 steps sequencer (maybe 32 steps).
So far I'd have 2 choices for the final number of steps CV adjustments.

- Standard CV pots sequenced with gates
  pros: cost is cheap, the note value is physicaly kept by each pots
  cons: bad note precision on large span (I'd like a 61 notes span on each
CV adj),
              span must be kept not too large..
- Rotary encoders
  pros: Very large CV span can be achieved on each steps (beyond 61 notes), 
             quantization easy to be achieved on each steps adjustments. 
  cons: expensive (are they all ?), need for data memory to keep every note
values (micro-processor needed)
All the gates could be generated by the same micro or from a precise
adjustable master clock

What do you think from your past experiences ?


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