ASM-1 up and running

Barry Bernard yrrab at
Fri Oct 4 06:46:50 CEST 1996

>Okay, I got my drill... my pots... my jacks... my 7 pound steel 19x10.5
>inch panal.. my knobs...  I get to start building my ASM-1 panal this
>I will get some pictures up of it as soon as I finish it.

  Just thought I'd mention, I have my ASM-1 project up and running. I built it
with the maximum amount of pots and jacks. Almost everything worked
perfectly right off the bat. It sounds great ! I'm still ironing
out a few problems here and there. One thing I recommend is soldering in the
"optional" 30pf capacitor across the feedback resistor of the VCA, otherwise
you will get high freq oscillation on the output of the VCA's, only at a certain
control voltage input level. This can be heard as "clicking" when you modulate
the VCA every time you pass that certain voltage. Adding the capacitor gets rid
of the problem.
   One thing that has me stumped is that the with really low frequencies
(like less than 1 hz), the output of the LFO seems to be asymetrical. On
the triangle wave, the rising part takes a lot longer than the falling
part. On the square wave, the voltage stays low for much longer than it
stays high. I believe I just used a ceramic dip capacitor, could this be
the problem ? Apparently it's discharging faster than it's charging at low
frequencies. Also, although my LFO goes well up into the audio range, it
stops oscillating when it gets below around .2 hz. Of course I'd like the
LFO to do really slow sweeps. As far as I know I put the proper components
  Anyone have any suggestions ?



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