When I got the Polymoog it didn't have the Polypedal to go with it. This is unfortunate because it can offer a lot of useful control, especially of the filter cutoff. On the other hand I really don't need a giant, dusty, probably broken, 30+ year old box that can only be used with one synth. I started doing some digging to see what my options were. First a run-down of the controls on back panel:
There's S-TRIG OUT and KB OUT. The Polymoog has a built in monophonic keyboard circuit that is used to trigger the filter, provide filter keyboard tracking, and control external synths. The Polypedal doesn't use either of these. I also didn't need either for my purposes, although the S-TRIG IN plus a screw driver to short it is very handy for troubleshooting the filter envelope.
The SWELL, FILTER, MOD AMT, and PITCH are all 1/4" TS 0-5V controls that are intended to be provided by the two expression pedals of the Polypedal. The EXT SYN, SUSTAIN, TRIG MODE, and GLIDE are all 0.206" 3-conductor jacks that are triggered by a contact closure between the tip and ring of a TRS plug. On the far right are the two accessory power outputs. In part 1 I'll be talking about the SWELL, FILTER, MOD AMT, and PITCH connections. In part 2 I'll talk about EXT SYN, SUSTAIN, TRIG MODE, and GLIDE.
The first thing I decided was to use a modern expression pedal, specifically the Moog EP-2. While some of the reviews I read weren't great (along the lines of "not nearly as bad as the EP-1"), I liked that it had an attenuator knob. Also it's from the same company, so at least it matches the Polymoog logo-wise. The EP-2 manual can be found here. It uses a 1/4" TRS plug with Sleeve = ground, Ring = 5V, and tip = output voltage. So my problem was how to get 5V to the EP-2. My options were the following:
- Add external power to the EP-2, e.g. add a 9V battery.
- Replace the Polymoog CV jacks with 3-conductor jacks and rewire to include 5V.
- Use the 5V from the accessory output like the Polypedal.
I decided on option 3. It was the least work and it would keep the Polymoog and EP-2 unmodified. I figured I needed three things-a 1/4" male TS plug, a 1/4 female TRS jack, and a 6-pin male Cinch Jones connector for the power. Then I had a revelation. Rather than get each of those and try to wire them together, I could just get a Y connector with the 1/4" female TRS jack and two 1/4" TS plug. I could cut of the appropriate TS plug and replace it with the Cinch Jones connector. The first thing I found was a product from Hosa, the YPP-136. It was inexpensive and even available at Guitar Center. However, once I saw it I realized a problem, it wouldn't be long enough to reach the accessories jack. I could extend the cable but that defeated the purpose of finding a pre-made connector. After a little more research (amazon similar items) I found a Monster Cable adaptor that could reach. It unfortunately cost $20 but I got it anyway. Please do not take this as an endorsement of Monster Cable. Monster Cable rants are welcome in the comments. After I got the cable, Cinch Jones connector, and EP-2 pedal I got to work.
The Cinch Jones connector needed to replace the 1/4 plug on the left. Verify with a multimeter. Monster doesn't even label the ends L and R.
Cinch Jones connector
Monster Cable stripped. The red wire needs to connect to 5V. Ground and shield are left unconnected since they will both be connected to ground at the Polymoog control input jack. Make sure ground and shield are cut off and aren't contacting any pins on the Cinch Jones. Heat-shrink would have been a good addition in hindsight.
Accessory connector view from inside the Polymoog. 5V is yellow. Note that the connector is "polarized" and the red and green pins are a little bit farther away then the others. Make sure you solder to the right pin on the Cinch Jones connector.
Final result with everything connected. It's definitely a stretch.
Here's what the result sounds like. In the first part I'm lightly controlling the filter cutoff on a patch based on "String." Second I'm attempting to be funky on a patch based on "Clav." Third I'm using the pedal hooked up to SWELL on a patch based on "String." Notice the high level of noise between examples. That's because I don't have the shield board under the filter/output board...and because the Polymoog is a noisy MF to begin with.
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