[sdiy] ring mod/asm-1 lfo

[harrybissell]

pass it through a diode (cathode facing the ring modulator input) and
ADD a pulldown resistor from the ring mod input, if it does not already
have one.

You will sacrifice about .7V from the high level of the square wave, if you use
a shottky
diode that could be .3V  (better)

The rise time will be the same as the original square wave, the fall time could
be much
greater because you are relying on that pull down resistor to er.... pull down.
The lower
the resistor value, the faster the response... until you get too low for the
square wave source.
It might be worth playing with...

H^) harry

gregory zifcak wrote:

> ah, that makes sense. is there some way i can remove the negative portion of
> the square?
> thanks,
> greg
>
> >From: Scott Gravenhorst <music.maker at gte.net>
> >Reply-To: music.maker at gte.net
> >To: synth-diy at dropmix.xs4all.nl
> >Subject: Re: [sdiy] ring mod/asm-1 lfo
> >Date: Sun, 24 Oct 2004 19:33:44 -0700
> >
> >My guess is that it's a 4 quadrant multiplier.  You're square wave is
> >probably
> >AC, meaning it spends some time above zero and then some time below zero
> >(absolute value of the voltage would be the same).  So what's happening is
> >the
> >ringmod is merely inverting your signal when the LFO is negative and not
> >inverting when the LFO is positive.  You really should hear only the clicks
> >as
> >the square wave changes states.  To get a tremelo effect, you'd want the
> >negative half cycle to be, say, 0 volts instead of negative something.  It
> >sounds to me like it's working perfectly.
> >
> >
> >"gregory zifcak" <zifcak at hotmail.com> wrote:
> > >hi,
> > >i am building the roman sowa ring mod with asm-1 lfo (with a .1 uF cap)
> >as
> > >the oscillator and it works great! except that in both ac and dc modes
> >the
> > >triangle does tremolo, and the square doesn't. the square is definitely
> > >working to my ears, but when it gets sub audio all i hear is the clicking
> >of
> > >the edges and the other source comes through fine. my first suspects were
> > >that i did the dc filter portion wrong, but the tri wave works sub audio.
> > >any ideas?
> > >
> > >thanks in advance,
> > >greg
> > >
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