MS-20 filter response

[Harry Bissell]

I'm simulating the MS-20 with EWB and when I get to the high resonance
settings (square wave input) I get the normal decaying sinusoid (ringing) only
on on the positive going edge. Negative side looks like Q has little or no
effect. I'm using an LM13700 model in place of the LM13600.
 
1) Can anyone confirm/deny that this is how the real circuit behaves?

2) Any experience with the LM13600 vs the LM13700 ???

The one-sided resonance looks cool, I think it probably sounds good too.

On another topic, can anyone point me to a synthetic inductor circuit
(Gyrator) that will synthesize a "floating" inductor. Most Gyrators synthesize
an inductor with one leg grounded. I want to play with the mook ladder some
more (without the real inductors) I found a 1994 design idea on a "Negistor"
which synthesizes a negative resistance so that the gyrators can be made
lossless (very high Q). If I can get someone to scan it I'll post it here.

Thanx :-) Harry

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