Tau Systems 1010 Filter

[Gene Zumchak]

Terry and Martin,

    Terry, that might just work.  The ladder is now a high pass.  The inductors
will be somewhat more expensive than caps.  It depends upon what the required
value works out to be.

    Another idea.  If you put a low-pass in the feedback of an op amp circuit,
you get a high-pass.  Maybe an op amp can be put around a Moog ladder to do
this.  I'm not quite sure where the input goes, though.

Gene


Terry Michaels wrote:

> Message text written by Martin Czech
> >Yes, as somebody pointed out, you have to replace the ladder rungs (which
> are C in the Moog LP) with a resistive element and the trannys with Cs.
> Doing this straight forward causes Problems, 8 Caps, and the resistive
> element isn't differential any more, how to bias ?
> So the resistive element is split up into a PNP to one rail and a NPN
> to another rail, and only 4 caps couple the resistive element knots. The
> original moog modular schematics are on the web (music machines, I think).
> <
>
> Hi Martin:
>
> Actually, there might be another way to make a high pass.  Replace the
> capacitors in the Moog ladder array with inductors.  Never tried it myself,
> though.
>
> Terry Michaels