PLAN B analog blog

>...
>OK fine no harm done, no fowl, right?  The bottom line is my VCO will
>not nail tracking perfectly...but none will.  Some will do better than
>others (read: ours) and there are reasons for this, most of which have
>to do with the incorporation of a Moog's octave switch which limits
>the range of the VCO to within what's called the 'linear region' but
>is able to offset that to higher or lower registers.  In this way, the
>circuit is responsible for tracking a much smaller distance, but it
>can move that gap higher and lower over the audio band.  If you want a
>VCO which demands keyboard tracking, this is the type you should stick
>to because this is the only config which will give you large-range
>keyboard tracking.

Whoa, whoa... Say what? I certainly defer to your superior knowledge, 
Peter, but this is contrary to my understanding of VCOs, so I'd love 
a little clarification. (A brief reply would be more than enough.)

I have not studied Moog VCOs in much detail, but I thought that a 
VCO's octave switch just adds different voltage offsets to the pitch 
CV. All the VCO circuits that I know of use this technique. It's not 
as though different capacitors are switched into the circuit for each 
octave. Is the Moog different from the rest?

(Apologies for non-PlanB content, but I hope that it's relevant 
enough for everyone.)

John


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