[sdiy] Suggestions for oscillator coarse control methods?

[David G Dixon]

The reason I like octave switches, coarse, and fine pots is that sometimes
you want to grab a knob and go "rowwwrrowwww" - you can only do that with a
coarse pot.  However, the coarse pot should probably have a centre detent so
that it can be "stuck" in place for normal musical operation, which only
requires the octave switch and the fine pot (which has a range of a bit more
than one octave).

 

The ultrafine pot (which has a total range of about a semitone or less) is
really only for calibration purposes, and doesn't need to be on the front
panel at all.  Indeed, it could be a pot you plug into a header when tuning,
or a miniport (or, less conveniently, a trimpot) on the PCB.  I like to
calibrate by frequency powers of 2 (32, 64, 128 Hz, etc), so the ultrafine
pot is really convenient for dialing in precise frequencies.

 

  _____  

From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of
Mattias Rickardsson
Sent: Thursday, January 23, 2020 6:15 AM
To: Spiros Makris
Cc: synth-diy mailing list
Subject: Re: [sdiy] Suggestions for oscillator coarse control methods?

 

On Thu, 23 Jan 2020 at 11:31, Spiros Makris <spirosmakris92 at gmail.com>
wrote:

I am leaning towards an octave switch, fine and coarse pots.

 

One minimalistic combination could be:

 

- an octave switch with many octaves selectable plus a "wide" setting

 

- a tuning knob that spans an octave (or what you'd prefer) except in the
"wide" mode where it spans the whole wide range.

 

It all depends on the usecases, but having a super-coarse pot available at
all times could ruin the precision.

Btw, the above could be combined with a finetune knob as well, if that's
desired.

 

/mr

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