Moog Music Forum

I've found a couple old posts in this forum stating that the following is possible, but I'm wondering if anyone has actually tested it...
The goal is to create a -5 to +5 voltage range, a total range of 10v, but offset by -5v.
The voyager only spits out a 0v to 5v signal, yet it receives the -5 to +5 single in some of its input cv jacks , such as PAN.
Some on this forum have claimed that one can simply take a CV signal and send it into the CP-251's mult, and then take TWO leads from that mult setup, patch both into the mixer, and that will give you a combined range of 10v. To achieve -5 to +5, one can then simply use the offset knob to bring the 0 down to -5, and that's it.
Does this actually work?
If not, It seems a curious design choice to have their prized synthesizer receive control voltages that Moog's very own line of products can't even generate.

coilandmagnet wrote: Does this actually work?

Yes it does.

Have you tried it?
Is it exact? In audio multing, usually each time you pull a lead from the mult,
each individual lead goes down in level a noticeable amount. Is this the same for CV? And if so, does it matter very much? I suppose one could compensate by sending yet another mult lead into the mixer,
and attenuate the whole thing so that it ends up 10v.
Only reason I ask is because I'm planning to use it for panning, and is want left to be truly left and right to be truly right.
Thanks!

Yes, i tried it many many times. An LFO based panner for my Voyager has been my favorite trick for a while. But you have to remember this analog stuff, not calibrated for space flight. Contrary to what is written in the manual, the CP-251 mixer section is perfectly as ease outputting very close to 10 volts. Any excess will be cut off. Tolerances taken in to account you should be able to swing -5 to 5 volts from an expression pedal for example plus or minus .2 volts.

terrific. thanks very much for the help!

A little guidance from the KnobTweak files:



Hope this helps.

- Greg

This is great! I will definitely check out the knob tweak site. Thanks.
So just to be uber thorough and check all factors.. I assume that the disclaimer of "do not introduce any offset in all cases" is not applicable here with my desired application? I still retain the full 10v range even after offsetting to -5, yes? I need a result of -5 to +5.

coilandmagnet wrote:This is great! I will definitely check out the knob tweak site. Thanks.
So just to be uber thorough and check all factors.. I assume that the disclaimer of "do not introduce any offset in all cases" is not applicable here with my desired application? I still retain the full 10v range even after offsetting to -5, yes? I need a result of -5 to +5.

You should be fine for this application, and be able to get the desired voltage range without difficulties. That said, it's always smart to be careful and methodical with messing around with offsets.

Offset has many uses. Besides various Moogerfooger applications, one Voyager/CP-251 example that immediately comes to mind is the Voyager Keyboard Inversion trick, which uses the Mixer Offset control to re-tune the Voyager after getting the inverted scaling adjusted:

KT > Files > Voyager >Inverted Keyboard Trick.jpg

I'm sure you'll come up with many others. Please share 'em on KT.

Have fun!

- Greg