[sdiy] microcontroller MIDI sequencer

[Peter Grenader]

It's all up to personal preferences, but I would think a standard pot along
with a quantized prcessing output to be the way to go.  This way yo could
have 'between the detent" tuning, plus 12 tone quantized tuning through
separate outputs.

As far as the tactile 'feel' of clicking into a 1/2 step, I'm not so sure
this is worth the disadvantage of being locking into quantized outputs only.
Surely one would be immediately aware if the pot had been tweeked enough to
go into a another quantized step simply by listening to the osc 1v/oct input
osc being controlled.

The idea of having a second fine tune control with a center detent would be
problematic - you would need to use matched 1% resistors for the summing
plus a trimmer for each step to tune the center point.  Trust me on this, I
just ent through this with the Gizmotron design.  You cam easily make a
bipolar pot, but to assure that the center is null, you'll need a trimmer to
compensate the offset due to component variances form circuit to circuit.

So at this point, we're talking three different controls which would need to
be summed PER step, with another two for the final summing.

my 5.1 cents,

P 


Glenwrote:

> 
> At 07:37 PM 3/19/03 , John L Marshall wrote:
>> Or quantize.
>> 
> 
> Yes, but quantizing alone will not provide the tactile feedback of a
> 12-step detented potentiometer. A 12-position switch will.
> 
> The only potentially serious disadvantage is not being able to select
> values "between the detents." If this is a problem, you could add a normal
> potentiometer as a "fine tuning" control. If you want the fine tuning range
> to be bipolar ( +/- ) then you should consider using a pot with a single,
> center-detent. Otherwise use a normal non-detented pot, and keep the fine
> tuning confined to either plus or minus adjustments, but not both.
> 
> At this point you are probably wondering, "why not just use a 12-step
> detented pot?" Well if money is tight and you can find a cheap supply of
> such pots, then go ahead. It would save one control. However, the separate
> switch and fine-tuning pot will allow for more precise adjustment of the
> exact value. Detented pots tend to be awkward to set to values near, but
> not exactly on, the detented value.
> 
> My last suggestion is to modify a conventional detented pot by replacing
> the detented cam inside the unit with a home-made cam, having 12 detents.
> This might be very difficult to do properly, but it would give you exactly
> what you wanted.
> 
> Later,
> Glen
>