[sdiy] 32 channel analog sequencer?

Peter Grenader pgrenader at mksound.com
Thu Jun 6 14:05:54 CEST 2002

There is another way of doing this you guys might want to consider.  If the
task is to create a sequence with up to 32 steps,  why not just ping-pong
the outputs of two 16 step banks, one after another.  It's really quite easy
to do ths, as I just went through it on my 2 bank 8 step design. Use the
last step of each bank to change flip flop states, have the outputs of that
FF gate an analog switch with the sequence bank outs going through it.

The only downfall is if you wish to reset the sequence with less than the
total number of steps (32).  Admittedly, this is a big downfall.  A way
around it tough would to have 32 pulse outs (2 per step), with the second
out of each step being enabled by the same flip flop state that's allowing
the ping-pong of the voltage outs.  I hope I'm being clear:

Two pulse outs per each step (of sixteen total).  The first would fire when
the sequence was in it's initial flip-flop state (step 1 thru 16), the
second would only be enabled in the second state (step 17-32) when the bank
two voltage pots would be 'live'.

If you elected however to make asingle counter that did 32 discrete steps,
you with this manyI would strongly suggest you include pulse inputs to each
channel which force the sequencer to go and hold at any given step until the
pulse is released or another channel input pulse is received at another
step.  Could you imagine what a job it would be to tune all of these while
the sequence is running?  yikes



on 6/6/02 3:27 AM, Ken Stone at sasami at hotkey.net.au wrote:

> 12 way switches by Lorlin or Alpha will cost the same as their lower count
> devices. In fact 7 postion is a bit odd - you would most likely have to use
> a 12 way with a stop-washer to get 7 positions anyway.
> Ken
>> andy wrote:
>>> I always wanted a sequencer with a five-way switch for octave and
>>> a twelve-way switch for chromatic note, since most of my sequences are
>>> quantized anyway....
>> I've been thinking about a 7 way switch with a switch with a secondary
>> resistor for the sharps/flats (standard western scale I suppose).
>> seems like a 7pst switch would be easier/cheaper to find than a 12.
> _______________________________________________________________________
> Ken Stone   sasami at hotkey.net.au
> Modular Synth PCBs for sale <http://www.blaze.net.au/~sasami/synth/>
> Australian Miniature Horses & Ponies <http://www.blaze.net.au/~sasami/>

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