To use CEM or not.

[harry bissell]

I modified the Pro 1 filter to give a 12db/24db response... and also tried it as a
state variable filter (see data sheets)...
The stae variable wasn't too good, did not give nice high Q and overloaded easily
and nastily (not nice-nasty...) so I trashed it...

The tapped filter is very cool, and doesn't require multiple pole switching.... I
recommend it...

RSVP if you want a schematic of the mod... :^) Harry

WeAreAs1 at aol.com wrote:

> In a message dated 9/21/99 9:38:25 AM, you wrote:
>
> <<Seems like I heard the 3320 was not that great a filter, but I could be
> wrong. Must be some reason there are soooo many left....Maybe phasing is
> it's forte?>>
>
> It's the chip used for Lowpass filter in the Oberheim OBxa and OB8, as well
> as the Sequential Prophet V (rev 3.0 and up) and Pro-One.  None of these are
> really raved about by those in the know, but they're certainly not terrible,
> either. (the older Rev 1 and Rev 2 Prophets had the legendarily sweet SSM2040
> filter chip)
>
> Voce used the 3320 in Allpass configuration in most of their Hammond/Leslie
> simulator products, as a Leslie simulator.  As far as I know, Voce was one of
> OnChip Systems last regular customers for new parts.  That's probably why
> there are so many of them left over - it was a relatively recent production
> run.  I think Waldorf was also using 3320's in some of their products of the
> last decade: possiibly in the first MicroWave and maybe even in their big
> Wave synth.  (they might even still be using them...)
>
> Anyway, there are six 3320's in the Voce "Spin" Leslie simulator (three for
> the Left signal, three for the Right, each side also split into low/high
> frequency bands).  However, the way they're using it and the way they're
> modulating it, it doesn't really sound like a phaser, but it's pretty darn
> good as a fake Leslie - especially considering that it's all analog.  One of
> these days I'm gonna go in there and reverse the circuit to see what they did.
>
> Michael Bacich