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Re: [motm] Mock up the MOTM-390 uLFO

2001-12-05 by George Kisslak

I like Ken's idea for a multi-phased LFO.  So I've added a bit to it.  Ok,
here's my humble attempt...

c) 3 pots, 1 switch, 1 LED, 4 jacks:

       RATE
        (O)
        FM
        (O)
       SHAPE
        (O)

    SIN     led
     + SAW  (*)
   PULSE

  (FM IN)   (0 OUT)
  (120 OUT) (240 OUT)

RATE, FM and SHAPE pots, and FM IN jack operate like the 320.  SAW, SIN or
PULSE wave output is selected by 3-position switch.  TRI is attained by
setting switch to SAW and SHAPE is mid-setting (just like the 320).  The led
is bi-color and works like the 320.

Advantages:
1) quadrature LFO!
2) basic 320 functionality in 1U good for those SKB dudes, but differs
enough from 320 to make it interesting to all
3) circuitry similar enough to 320 that it should be quick to implement
(NAMM!)
4) all std waveforms available
5) FM IN
6) blinky LED!

Disadvantages:
1) no SYNC
2) no 1V/OCT IN
3) no SHAPE IN
4) only one waveform available at a time
5) blinky LED!

I for one think a sine output is very important for proper sounding vibrato
& tremolo, so it's included even though I'm sure it involves additional
circuitry.  I realize that this design may actually involve more circuitry
than the 320 (due to the phase shifted outputs) but Paul has always said
that circuit parts are much less in cost compared to front panel parts.

George

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