Sunday, 25 December 2016

Emu & Serge for Xmas




A Christmas patch on the Emu and Serge modulars. This was not an easy sequence to set up due to the extremely quirky nature of the early Emu digital logic implementation, but I wanted to test the step sequencer which is capable of generating 32 control voltages if you set it up correctly. There is very little info out there on these modules, and what I could find (the 1978 Emu Systems Catalog, and a more detailed manual called the Emu Modular Synthesiser Operation Manual Retrospective) only had some fairly oblique references to the patch required. Suffice it to say that it took me about 3 days to work it out and plenty of phone calls to Big Al (who knows a lot about early digital logic). It goes something like this: take a clock source and patch it out to the 8 Position Address Generator taking the 'Carry' output trigger (which happens at the end of the 8th step) and mult it out to the 3 clock inputs of a Triple Latch which needs to act as a ring counter. So use the 3 'Q' outputs to feed into the next Data input of each latch with Q3 feeding back into Data 1 to make it cycle. That gives you 3 steps. The clever bit is making the 4th step which means taking the 3 '-Q' outputs and multing them together to generate a clock on every 4th cycle (whenever an "all zero" state occurs). Patch the 4 outputs of the Voltage Source Unit into the 4 ins of the Analog Switch and use the newly created 4 stage ring counter to step through them. PHEW! The rest of this patch uses the Serge to generate some percussive sounds including the Wilson Analog Delay and Spring Reverbs. Its a live single-take jam-up