[sdiy] filter help

[Theo]

Hi Mark,

Your question seems to be about filter topologies or "how to connect
components to get a filter".
http://www.maxim-ic.com/appnotes.cfm/appnote_number/1762/ln/en
BTW What you seek is not there.

Mr Bessel, Butterworth, Chebyshev and fellow filter types are about the
component values and resulting behavior of your filter.
http://www.maxim-ic.com/appnotes.cfm/appnote_number/733/ln/en

Maybe a 6dB filter is good enough for your application?
There might be other solutions.
What is the other half of the stereo pot doing?
Maybe its possible to free it up.

Cheers,
Theo



----- Original Message -----
From: mark s <djarum11 at mindspring.com>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Sunday, October 26, 2003 5:27 PM
Subject: [sdiy] filter help


> greetings everyone,
>
> i am trying to build an active, tunable HPF (2 pole is fine) using no more
> than one opamp stage and one section of a pot (i.e. not a dual-ganged
pot).
> also, it should have good phase characteristics and a small parts count.
>
> it seems to me, from my limited perspective, that a Bessell requires a
> dual-ganged pot for changing the frequency, so i have ruled it out. can
> anyone enlighten me or point me in a direction ?
>
> thanks!
>
> mark scetta