Phase Shifting Feedback

[jh]

On a Moog phaser, you can select the number of phasing stages
and the number of feedback stages independently. (On the old
12-stage, that is. What about the new Moogerfooger one ?)

I have breadboarded a 12-stage vactrol phaser once, with ptch points
for all stages, and yes, you can get a great variety of effects with
different combinations. This experimental board is not 100% working,
though (HF oscillation problems in certainconfigurations), and I haven't 
found the time / priority to give it another try yet.

As for feedback, both positive and negative is useful. But make sure
that you have a slight low pass and / or amplitude limiter in the feedback loop
to avoid unpleasant screaming.

JH.

-----Original Message-----
From:	Sean Costello [SMTP:costello at seanet.com]
Sent:	Tuesday, April 13, 1999 6:58 AM
To:	synth-diy at mailhost.bpa.nl
Subject:	Phase Shifting Feedback

Hi all:

Have any of you DIYers out there experimented with taking the feedback
signal for a phaser from a stage besides the last stage of a phaser? I
know that the Schulte Compact A is an 8-stage phaser that has a feedback
loop around the first two stages. What impact does this have on the
sound? From my own digital experiments in Csound, the resulting sound is
less like an 8-stage phaser - it sounds a bit more "low-fi." Has anyone
experimented with this in the analog realm? 

Also, is phaser feedback usually negative or positive?

Thanks,

Sean Costello