[sdiy] Korgasmatron vs MS-20

[Stewart Pye]

Hi David,

Good to hear the filter sounds similar.

2. If one were to use an LM13700 as a sine shaper in a VCO design the 
other half may be useful on the sawtooth signal to get some soft clipping.

3. You can always add in distortion...

Regards,
Stewart.


David G. Dixon wrote:
> Yesterday, I had the chance to put the 2164 Korgasmatron Dual VCF head to
> head with a real live Korg MS-20 (the older, KORG35-based version).  I'm
> happy to report that they sound virtually identical.  The only real
> differences are that the original has a narrower (and, for performance at
> least, more user-friendly) range of cutoff frequency, and a slightly
> different relationship of frequency to pot knob position.
>
> One thing my system (not the filter per se) does not emulate very well,
> though, is the warmth of the MS-20.  I think this has to do primarily with
> three things:
>
> 1.  The MS-20 is very noisy, and this noise originates well back in the
> signal chain and is subsequently processed through the filters and VCA.  My
> system is virtually noise-free.  Mixing a touch of white noise into the
> filter along with the (very precise) sawtooth wave from the 2164 Expo VCO
> brought the sound of my system somewhat closer to the MS-20.
>
> 2.  The oscillators in the MS-20 are probably not very precise.  Although we
> didn't look at anything on a scope, it sounds to me as if the sawtooth wave
> generated by the MS-20 is a fairly round-shouldered affair.  This produces
> the equivalent of a slightly LPF'ed sawtooth wave going into the MS-20
> filter which has very little of the "buzz" associated with a pure sawtooth.
>
> 3.  The VCA in the MS-20 is a single-transistor cheapo affair which, again,
> is probably not very precise and thus adds a bit of warmth and distortion to
> the signal.  My VCAs is based on linearized 2164 VCAs, and it is very
> precise.
>
> In any case, I am very happy with how my filter stacked up against the
> original.  However, one of these days, I'd really like to develop a
> rack-mounted clone of the MS-20.  It is a beauty!
>
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at dropmix.xs4all.nl
> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>
>