[sdiy] Best Way to limit control voltage

[Grant Richter]

One thing to note is the linearity about the clip point.

The simple methods become non-linear over a larger range before limiting.
And the limiting may have a "bow" in it (not flat).

An op-amp limiter should be linear exactly to the limit point and then have
a perfectly flat response after.

BTW, if you sum the negative of a peak limiter output with the original
signal, it acts as a base clipper since the signals cancel unless the
limiter is engaged.

I once saw a picture of a Moog 900 module that had 4 individual controls for
positive base clipping, positive peak clipping, negative base clipping and
negative peak clipping. I always thought that was pretty slick.

> From: Tony Clark <clark at andrews.edu>
> Date: Mon, 14 Mar 2005 17:38:33 -0500 (EST)
> To: Synth-DIY <synth-diy at dropmix.xs4all.nl>
> Subject: Re: Re: [sdiy] Best Way to limit control voltage
> 
>> From what I can see, this above will rectify everything. With a
>> zener, you could pass an undisturbed sinewave, with only the peaks
>> being limited past the zener voltage.
>> Someone correct me if I'm wrong though. I'm no engineer.
>> More of a "if it works and doesn't draw too much current, it's
>> probably ok" school ;-)
> 
> I'm quite fond of using zeners myself for limiting voltages.  I use
> this trick in front of A/D converters.  In order to prevent unnecessary
> current draw, I put a very small resistor in front of the zener which
> allows the incoming CV some extra overhead, but the output remains
> clipped quite nicely.
> 
> Cheers,
> 
> Tony
> 
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