[sdiy] VCA completed

[Charles Bisaillon]

Hi everybody,

Want to let you know that Sandeep and me finished the VCA today. It is
really nice, we implemented a ring modulator circuit in parallel with the
VCA by using analog multiplier AD633. The coolest thing is the switch that
was implemented, it switches between "in1+in2" or "in1+ring", which
determines the the audio output mix. IN1 is always fixed gain, IN2 is
variable gain and it controls the level of signal in2 in the output mix when
switched "in1+1n2". When switched "in1+ring", signal in2 is not present in
the output mix, instead, the output of the ring modulator is being fed to
signal path in2. In this mode, the in2 gain knob controls the output level
of the ring mod only, which determines the amount of ring mod signal to be
mixed in with in1 at the summing node.

All this fits nicely on a "1 rack unit" MOTM style front panel with 3 knobs,
6 jacks, 1 led and one switch. Very nice job on that one.


Charles

http://www.oveloe.com/490/