The BugBrand SYN2A VCO is really nice.  It has a jumper to select the variable FM input to be exponential or linear.  Since it also has a 1V/octave exponential input, I selected linear for both VCOs.  In this recording the two SYN2As cross modulate each other by patching from the Triangle/Saw output to the linear FM input of the other.  These outputs are taken also to the Cocoquantus, where they receive amplitude modulation going in.  Additionally, one control output from the Nabra is attenuated and taken back to one of the SYN2A’s 1V/octave input.  I played with the FM depths and some of the Cocoquantus controls.  Coco delays were not used.