I’ve heard that you should NOT plug multiple CV sourced into a passive Mult, that you need a mixer to safely combine Voltages, etc. Understood…
If I take CV from one device (say a CP-251) and want to feed it to two expression inputs (say another Moog LFO and a Fooger), how do I go about this? Logic would suggest, LFO on 251 into it’s Mult then one cord to the Fogger and one to the keyboard.
Doesn’t the CP-251 put out 5v on one leg of the tip/ring/sleeve jack (to receive the attenuated voltage on another leg? If my understanding is correct then I’ll have all 3 devices putting out their on 5V?
What am I missing here (besides knowledge and common sense?)
Thanks,
-Mike W. from NJ
Only jacks with the white rings on the CP-251 (white labels on foogers) and red jacks on the Voyager send a 5 volt supply to the ring to “power” an expression pedal. As you said, the role of the expression pedal (or input) it to convert that 5v to anywhere between 0 and 5 and make it appear at the tip. When there, it’s the CV.
Normally, you are going to use TS cables to do your patching. When using a TS plug in a Red/White input jack (expression jack), the 5v is automatically shorted to ground (by design). It’s just as if it does not exist and you don’t have to worry about it.
The possibilities go like this for the mult of the CP 251 or VX 351…
1- Insert an expression pedal (TRS plug) in a white ring jack.. pedals does its job, fed by the ring’s 5v, period.
2- Insert a TS plug (already carrying a CV on the tip) in a white ring jack and the ring’s 5v is shorted to ground, and you don’t have to worry about it since it does not exist anymore.
3- If you do not use the white ring jack and use other three instead, the ring 5v supply of the white ring jack is NOT passed to others jacks, they are tip-sleeve only.
4- Insert an expression pedal in a regular jack (non white label). Nothing happens, with no voltage on the ring, it’s a dead device.
5- Insert a TRS plug that carries 5v on the ring (coming from elsewhere) in a regular jack (non white label). Nothing happens. The ring contact on the jack is not connected to anything, so the 5v sits there harmless, with nowhere to go.
I hope this helps. It’s kind of my third try at writing, first two turned out pretty bad. In the end I thought the enumerative way was best.