As often happens with an electronic device, once it gets out into the hands of creative people more uses are discovered. For example, Jim Riter (an electronically-oriented keyboard player) wrote me to say that the Gnome/Guitar Interface circuit, published in the 4/76 issue of Polyphony, will also allow a guitar to trigger ARP envelope generators directly. It can also trigger Minimoog envelope generators via a reed relay; in this application, you will need a saturated transistor driver for the relay since the output of the Interface does not deliver enough current to drive this type of load, directly. Jim also suggests possibly using a 4016 CMOS switch as an alternative to the relay, since it would not require a driver transistor.

Incidentally, this circuit also gives a reasonably good envelope follower output, which you can tap off through a buffer at the junction of the 47K resistor and .22 mfd. capacitor, at the output of the second stage of the Interface. Happy Experimenting!