[sdiy] problem with 13700 flter upper range

[Dave Magnuson]

----- Original Message ----- 
From: "Dan Snazelle" <subjectivity at hotmail.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Tuesday, January 27, 2009 9:49 AM
Subject: [sdiy] problem with 13700 flter upper range


>
> OK
>
> i have gone through a bunch of filters on the breadboard this week and at 
> first was leaning toward a simple sallen and key with a vactrol for CV 
> control. however i didnt like having to have the cutoff knob go through 
> the vactrol...so i moved toward lm13700 based filters.

<snip>

Hi Dan,

Was the vactrol your only reason for dumping the S&K filter?     I'm 
assuming the slow response time was your problem?

If so, you could try using H11F3 opto-fets instead of the vactrol. 
They're plenty fast, probably cheaper, and easier to fit on the board 
(DIP-6).

Dave Magnuson