[sdiy] SSM2164 state variable filter

[Tom Wiltshire]

I've tried all of these possibilities on the breadboard.

To summarise briefly;

Asymmetric clipping gives an audible result, and doesn't sound bad if you're after a fuzzy sound.
I tried various types of diodes (including LEDs - the old fuzzbox trick) and there's no real difference between them in this application. I suspect this is because they limit the level and are thereby never driven hard enough to make a difference. Even Si/Germanium doesn't seem to make much odds.

The only place where I found that not to be the case was on the initial HP mixer stage. Adding diodes there is like putting a fuzz in front of the filter. Which isn't an entirely bad thing, obviously...

T.


On 15 Jul 2010, at 01:54, cheater cheater wrote:

> One thing that's interesting to me is how the matching of the diodes
> matters. What if you took the two diodes, and one of them had say a
> 20% higher voltage, creating some form of asymmetric clipper? Could
> sound nice, couldn't it?
> 
> What about different types of diodes - both types being the same
> voltage but everything else different (for some definition of
> 'everything else' that makes for interesting results) - how could the
> sound change when using one type of diode vs the other?
> 
> What about transistor clipping? Tube clipping? OTA clipping? Germanium
> vs Silicon? :)
> 
> Cheers,
> D.