[sdiy] Log and Lin Controls in a DIY synth - Where to use?

[Tim Parkhurst]

On 2/2/06, Chris Manders <wight446 at yahoo.com> wrote:
> Hi folks
>
> I am going back to my old love, Synths after a brief absence.
> About 6-7 years ago (seems like yesterday) I successfully built a Moog
> ladder filter and a VCO using help from some of you guys out there.
> I am going to start collecting up bits and bobs for continuing this project
> of building my first Analog(ue) synth.
>
> This will probably be a real Newbie question to you guys out there, but in a
> typical synth which Potentiometer controls should be Linear, and which
> Logarithmic?
>
> I understand what Log and Lin are, and this may be something I just need to
> get my head around to fully understand it.
>
> Am I right in saying that if a control describes a voltage level (CV to
> Pitch being 1V/Octave), then that control should be Linear. All the rest
> should be Log (as for example Amplitude being a Log scaling)?
>
> My head starts to ache when I think of other routings. If a Linear LFO level
> control is set to sweep up and down by 1 Volt, when fed into the VCO it will
> modulate the pitch up and down by an octave. Would this LFO signal then have
> to be converted to a Log scaling if one wanted to feed it to the VCA for an
> even tremolo effect?
>
> Thanks
> Chris
>

Hey Chris,

Welcome back to being a synth addict! You might get some good input by
looking at existing synths and seeing what type pots they use. I'd
check the Minimoog and the ARP Odyssey for starters. The Ody pot
values/types are listed here:
http://www.arpodyssey.com/odyssey-slider-values.jpg

I'm not quite sure where to find the pot info for the Mini, but I'm
sure a Google search would point you in the right direction.


Tim (pointed in approximately the right direction) Servo
--
"Imagination is more important than knowledge." - Albert Einstein