> Hi,
> So lets say I have a theremin module A178 and I want the entire range
> of control of the theremin to only affect one octave of pitch.
>
> I imagine I can do this with a A129-3 via attenuation and offset, is
> that correct

Yes. But the A-129-3 is not really necessary. Each VCO (A-110 or A-111) has
an CV input with attenuator so that you are able to adjust the sensitivity
of the CV coming from the A-178. And each VCA has an octave switch and
manual offset control available.

> If the output of the theremin ranges over 5 volts normally (is this true )

Yes. The max. output voltage is close to +10V (i.e. when you touch the
antenna)

> then if I attenuate it it will range over only 1 volt.... I hope.

yes

> Then I can offset the output so that the volt in
> question will correspond to the octave of my choice.

yes

> I think maybe it is also possible with the A138c using the offset
> function of input one.

yes. But not necessary from my point of view.

Best wishes
Dieter Doepfer