2720 and 4700 series patch cords, FatMan interface, insight
The patch cords for the modules consisted of 1/8" mini phone plugs for the audio cables and pin plugs for the control voltages/triggers. Flexible, rubberized test lead cable is good for the patch cords.
The pin plugs aren't as readily available as the 1/8" phone plugs, but Mouser 800-346-6873 has them (stk #530-105-0302-1) but they describe them as tip plugs. Mouser has the rubberized test cable too. Solid, 14ga insulated wire wire with about an inch stripped off at each end can be used for the cv patches. Test leads as used on inexpensive multi-testers are often the right size. Since everything in the 2720 or 4700 series systems is on the same power supply, they already have a common ground, so the cables need only be a single conductor wire. When patching to the external equipment, or between a 4700 series analog keyboard controller, one cord will need to be patched between a ground circuit jack (could be a black one?) on the synth and the device ground to establish a common ground between them.
flexible, rubber insulation, test-lead cablehttp://www.mouser.com/Search/ProductDet ... pXoKZdw%3d
Tip (pin) plugshttp://www.mouser.com/Search/Refine.asp ... 105-0302-1
Mini (3.5mm) Phone Plugshttp://www.mouser.com/Search/ProductDet ... 2bvQ%3d%3d
FatMan's Pitch and Velocity control voltage outputs and Gate trigger output are compatible with the inputs on the 4700 and 2720 series. To patch or connect one to the other, special cables would need to be made with a RCA Phono plug on one end and pin (tip) plugs on the other. Mouser Electronics website/catalog has Tip plugs and Phono plugs that can be soldered to wire or cable to make the patch cords. On the FatMan end, the center post on the RCA Plug is the control voltage or trigger and the shell is the ground/common. The 4700/2720 end would have two, and in some instances one, pin/tip plug. One is for the control voltage and the other for a ground/common at a multiple panel. If there isn't a multiple panel with a row of three ground pin/tip jacks, a 'dummy' mini-phone plug into an unused patch point can be used to establish a common ground with the sleeve terminal attached to the FatMan RCA Phono connector ground wire.
The most obvious patch would be to use FatMan's Pitch CV and Gate trigger as a substitute for the set from a keyboard controller in the 4700 or 2720 system. Velocity CV could be patched to a VCA input or VCF input for modulation according to the playing dynamics on the MIDI keyboard controller connected to FatMan.
A Phone plug to mini-phone plug cable can be used to patch the FatMan audio output to a VCF, VCA, or Mixer input on the modular system being controlled for further processing and or layering.http://www.paia.com/fatman.asp
This reprint of an article by John Simonton describing building and using the 2720R synthesizer is a good practical guide which you might find useful for connecting and using older 2720 and 4700 series synthesizer modules. http://www.paia.com/manuals/docs/2720-b ... rticle.pdf