[sdiy] Moog SL-8

[Tom Wiltshire]

On 14 Apr 2017, at 14:39, Dave Magnuson <abide at dmdrafting.com> wrote:

> 
> 
> -----Original Message-----
> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Tom
> Wiltshire
> Sent: Friday, April 14, 2017 6:44 AM
> To: rsdio at audiobanshee.com
> Cc: SYNTH DIY
> Subject: Re: [sdiy] Moog SL-8
> 
> 
> On 14 Apr 2017, at 04:27, rsdio at audiobanshee.com wrote:
> 
>> 3) How is 1.2V/oct "over-tracking?" That would seem like under-tracking to
> me, since 1V would produce less than an octave. Did Moog mean to say 1.2
> octaves per Volt?
> 
> I think they did mean 1.2oct/V. That was what I understood when I read it,
> and it wasn't until you pointed it out that I realised it was the wrong way
> around.
> 	
> ---------------
> I have a Crumar Spirit (and Bob Moog supposedly had a role in it's design)
> and it has a similar odd V/Oct tracking.   I don't have the manual in front
> of me but it's something along the lines of 1.1V/Oct output on the CV out
> and 0.9V/Oct at the CV input.
> 
> I always assumed it's to account for a bit of voltage drop... but it means I
> need a voltage scaler between my Crumar and my MIDI->CV.... which is a bit
> annoying :)
> 
> Dave

Doing the tracking adjustment at the CV input does seem pretty odd, but I do think filters should be able to track more than an octave per volt, so that you can turn the Keyboard CV amount knob up past 100% and have the filter open more for higher notes, as well as go below 100% so that higher notes become more filtered.
In most circuits the sensitivity of the CV input is just one resistor into the CV mixer, so it's not hard to do.

Tom