FatMan VCF External Input Scott R. Gravenhorst 15-Apr-1996 This circuit is a simple interface to the FatMan's VCF. The operational amplifier is any audio type. Because the VCF feeds into the VCA, you must trigger the FatMan or no sound will be produced. For example, if you are going to plug some kind of keyboard's sounds into the FatMan, make sure that the Keyboard's MIDI channel is set to the same one FatMan is using. In this way, when a key is pressed on the keyboard, it will trigger the FatMan and the envelope generator internal to the FatMan will operate and modify the sound piped into it. I have even tried this with a MIDI guitar! If you like external input, you should also modify the FatMan's mixer so that you have a level control for each VCO. This will allow you to cut out both VCOs completely so that you can play with your external input sound. My current email address is chordman@ix.netcom.com