Hurray a question! (slow weekend...)

[Harry Bissell]

Damn fuuny you should ask. I just got the TomG VCF8e (MS-20 clone) going...
and decided to try the linearizing diodes...

Very little effect on the integrating sections... probably because they are
(well...) integrators.  The effect was very slight and I think it might only
affect tuning....

Also tried on the Resonant Feedback VCA...  This had some effect, mostly to
reduce the overall gain of the feedback....   Not worth the effort IMHO...
Maybe I need to increase the gain back again to see the effect... but I'm
thinking more of making a resonance limiter for this puppy.  It's a cool
filter... Very Nasty at high resonance levels...  If you tune below the
input frequency, it starts oscillating and locks subharmonics....

Almost seems like the point of this filter is that its really an oscillator
most of the time... and it wants to beat, ring, etc... Can easily get very
ring-mod like effects, and VERY sensitive to input amplitude...

Not exactly what the spice sim I did would suggest....

Anyone else: Thoughts on the linearizing diodes ????

H^) harry

Tony Allgood wrote:

> Hi all,
>
> Blimey, it's a bit quiet today. So I've got a question for you all. Why
> do all the 13700/13600 OTA based filters not use the linearising diodes?
> Even in the app notes, they tell us how wonderful the linearising diodes
> are, but don't use them on the filters, just the CCAs. Got to be a jolly
> good reason.
>
> Regards,
>
> Tony Allgood  Penrith, Cumbria, UK
>
> Modular synth circuits, TB303 clone and Filter Rack
>
> http://www.techrepairs.freeserve.co.uk/projects.htm