[sdiy] Triggering problems with sequencer. Any thoughts?

[Peter Grenader]

Pulling gates is easy.  This is what you do:

Take the counter outs, or outs from a line driver after the counter (which
you should consider)   - whichever you do, tap off the inputs to the pots
(or rotary switches - however you're making voltage level selection) and run
them through NPN emitter-followers. This will increase your drive and more
important,  buffer the counter (or driver) outputs to the outside world -
you don't want to expose these signals to the faceplate because you'll screw
the internal counting to hell if you're running high loads on your gate
outputs .  For safe measure, after the e-f's, run the signal through series
diodes - thus protecting the e-f's  in case you accidentally connect an
output to them.  This will also allow gates outputs to be combined.

You can also use these counter/driver signals to drive the stage LEDs - but
make sure you do that before the e-followers or your brightness will vary
when the gate outputs are being used.

hope this helps -

- P  


Rykhaard D.A.M.I.A.N. wrote:

Thank you greatly all, for the answers!!  :D  I never even thought of
pulling the Gate or Trigger, from the Counter!  Major Duh on my part. :O
Haha. :D

I JUST realized, about 90 minutes ago at work - that I had to generate a
TRIGGER.  (Or so I thought, before I read your replies.)  Pulling the 'Gate'
off of the Summer Output, outside of allowing something of a Gate, when
there's a great enough change in voltage, to allow my 'gate cap' to
discharge, is having a continuous voltage, with no breaks - hence, the sound
of a synth, in legato. :(

Shortly after I'd typed the initial message, on the way to work, I thought
harder on the use of another 4051, for multiplexing a Gate to 8 individual
Gates (Summing each to a single output, with a switch On/Off for each).
As the idea developed through the day, I thought that a single ON/OFF/ON
switch, could allow either of the following sets of Gates, to occur:

1 - first 4 bits
2 - last 4 bits
3 - all 8 bits

That could give many interesting combinations of notes, with the pair of
rotary switches per step.  And there's still room on the board, to cut away
existing copper for mounting another 4051 onto.  So that's my plan for that,
tomorrow morning, before I hook up the 2nd set of rotaries.

Now ...... to figure out how to generator the Gate and / or Trigger, from
the counter.  My biggest fear (from no previous experience with this,
outside of building envelope generators) is having a constant voltage again
......  shall see what I can figure from your suggestions above, as well as
checking out what other's have done in their sequencers. :)  Many thankees.
:) 


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