[sdiy] Updated Schematics of Rene/Wasp Hybrid

[Ryan Williams]

aaron,

I already sent you comments on this, maybe you didn't get it, or maybe
ignored it. Since it sounds like thier circuit is not perfected yet, 
take a look at my experience with this circuit (if you haven't already):

http://www.sdiy.org/destrukto/files/cmosed_ms20_filter_11-18-2005.pdf
http://www.sdiy.org/destrukto/mp3/cmosed_ms20_sweeps.mp3
some description and a scope shot with resonance is on my main page:
http://www.sdiy.org/destrukto/

Take a look at my biasing scheme, it worked well. There is a comment
about generating +7.5V which is probably not right, I went a little dumb
when I tried to do it with an unused inverter.

I have messed with the feedback circuit gain. This turned out to be
important to make the thing self-oscillate using certain 4069 chips I
had. Different 4069's made a big difference for the feedback. the
distortion in the feedback seems to be the key for an interesting sound.
I still wonder how it compares with the opamp version.

On my circuit, I have the second stage with the cap in the 4069 feedback
instead of resistors. I found it worked a little better like this, but
there's not that option on the first stage.

The filter growls nicely with high res and low cutoff. I liked it quite
a bit and plan to do more work on it later. the schematic doesn't show,
but I was using non-polar electrolytic caps.

-Ryan Williams (am considering doing a discrete version of this filter
structure)

Aaron Lanterman wrote:
> 
> Dear Kai Chi and Sean - this is very interesting. I'll forward to the
>  SDIY list.
> 
> List folks: You can see the new schematic at
> 
> http://users.ece.gatech.edu/~lanterma/ece4803/drafts/renems20_wasp_crossbreed.bmp
> 
> 
> 
> or in general just 
> http://users.ece.gatech.edu/~lanterma/ece4803/draft
> 
> So now you get interesting effects as you change the resonance knob? 
> If so, I'd say you're close to ready to commit this to 
> perfboard/stripboard/veroboard/whatever.
...
> 
> - Aaron
>