I was trying to make a second mod wheel in a separate enclosure for my model d. I am using the mp-201, which has it’s own attenuator, but I already use the pedal for filter cv, so I want a simple cv attenuator to free the pedal up and without using the MP encoder to introduce modulation to vol and pitch. I have a mod wheel assembly with a 100k pot j-type. Is this all i need? And how would I wire this? I have two 1/4" ts jacks, but I am a little confused how to ground the pot and jacks. BTW I am an EE novice.
Life isn’t going to be simple here. 
The Mini is unique in that it’s wheel is sort of wired up backwards.
Instead of turning up modulation in a clockwise fashion (like a knob), it actually shorts it out as it’s turned counter-clockwise.
Modulation is actually on full all the time.
When the wheel is down, it’s shorted to ground.
The taper of the pot has to be an audio (expo) type. Not linear.
It just doesn’t feel right. (no idea how it would feel on a pedal tho.)
The pot also has to reach less than an ohm when shorting out the modulation.
Not all pots do this. (the spec is known as “end resistance”.)
If it doesn’t short it out enough, mod bleedthru will occur.
On a Mini, even the wire resistances in a cable are enough to make using an external pot unrealistic.
You’d probably have better luck using a vactrol or a true VCA to control modulation than trying to use a pedal directly as the mod pot on a Mini D.
I appreciate the reply. I am not looking to modify the mini at all, just to use the ext pitch cv input for modulation. Maybe I overcomplicated my post, I just want a pot to attenuate cv coming from my mp-201.
I don’t care about bleed or taper, just attenuation. I bought a mod wheel assembly with 100k pot that parted out from an old synth, so it should be fine, right? An attenuator can’t be that difficult, or am I out of my league.
I guess I’m confused too.
If you want to use the pot from the wheel as an attenuator, that’s possible.
Facing the front of the pot, left terminal is ground, middle is output, right is signal in.
Thanks, I thought it might be simple, but for some reason my voltmeter reads strange values, so I thought I might be missing something.
Scratchy pot maybe ?
Unlike the Voyager, the Model D has no ring output voltage. The 1120 expression pedal is an active device (carries it’s own voltage), while an expression pedal for the Voyager is a passive device, powered with the ring voltage of the CV jack.
To use your mod wheel (without the MP-201), you need to convert it to an active device. You will need a 100k resistor (to create a voltage divider), a 9 volt battery and connector for it, maybe a switch to power it on and off.
Google the Moog accessories service manual and see how the 1120 pedal is wired. The 1120 has a switching jack, you probably don’t want to go into that. The above is simple and will suffice. Actually, if you remove the plug from the CV jack when not in use, the battery will not draw any current, so the switch is really optional. Watch out though, it will be live (a few milliamps at 4.5 volts) 
so the switch is a good idea anyway.
It was a bad solder on the ground, got it working.