[sdiy] first filter ?

[harrybissell]

The low pass gate (in lowpass mode) is a Sallen Key filter. It (by
itself)
has a 12dB slope.  By playing with the gain of the opamp after the two
optos, you should be able to get reaonance and even oscillation.

Be aware that Sallen Key filters are really ill behaved once they
oscillate...
they will rip your head right off...

H^) harry



dustin sedlacek wrote:

> i am looking to build a filter ...my first i like the low pass gates ,
> they seem very cool and i understand that with 2 of them and a basic
> mixer i can get resonance ? how is this ? what kind of slope would i
> get ? 12/db ? can i get a sharper slope ? what about a 6 db slope ?
>
>
>
>
> sorry for the double post for some
>
>  On 6/9/05, Ray Wilson <raywilson at comcast.net> wrote:
>
>       Check
>      out: http://www.musicfromouterspace.com/analogsynth.php?page=ANALOG Click
>      filters. Cheers Ray
>
>           ----- Original Message -----
>           From: dustin sedlacek
>           Cc: synth-diy at dropmix.xs4all.nl
>           Sent: Thursday, June 09, 2005 1:15 AM
>           Subject: [sdiy] first filter ?
>
>
>           i am looking to build a filter ...my first i like
>           the low pass gates , they seem very cool and i
>           understand that with 2 of them and a basic mixer i
>           can get resonance ? how is this ? what kind of
>           slope would i get ? 12/db ? can i get a sharper
>           slope ? what about a 6 db slope ?
>
>
>
>
> --
> Dustin