[sdiy] more pitch shifter thoughts

[rkmoore at memphis.edu]

was it the EML Polybox, or something like that?

----- Original Message -----
From: harrybissell <harrybissell at prodigy.net>
Date: Saturday, January 8, 2005 2:30 am
Subject: Re: [sdiy] more pitch shifter thoughts

> There was a commercial product that did what you describe... it 
> was a
> box that made
> a single octave of chromatic notes, polyphonic... from a monosynth 
> vco.It had a single
> octave keyboard. Forget the name... someone will remind me :^P
> 
> H^) harry
> 
> PRCamann at aol.com wrote:
> 
> > In a message dated 1/3/2005 11:04:29 PM Eastern Standard Time,
> > rtellason at blazenet.net writes:
> >
> >
> >> I got to thinking about this subject some time back,  and came up
> >> with some
> >> thoughts about things that may or may not work,  I never did get
> >> around to
> >> playing with this idea.  Maybe you all could tell me why it 
> wouldn't>>
> >> work?  :-)
> >>
> >> Suppose you took a PLL circuit,  one input to the phase comparator
> >> would be
> >> some filtered version of your input signal.  (The filtering 
> would be
> >> one of
> >> the tricky parts,  I guess.)  The PLL is also running a top-octave
> >> chip,  and
> >> maybe (maybe not?) some divider stages,  depending.  Things get set
> >> up so
> >> that the lowest "note" available comes out at the same pitch as the
> >> filtered
> >> version of the input signal...
> >>
> >> Then you've got the rest of the outputs,  the other "notes",  and
> >> maybe
> >> octave-related versions of it,  all of which are going to be square
> >> waves of
> >> course (unless you get one of those oddball top octave setups that
> >> produces
> >> an assymetric output waveform for higher harmonic content),   
> but in
> >> any case
> >> more filtering is going to be needed here...
> >>
> >> Take a selection of those outputs and you've got "chords".  Mix
> >> them,  do
> >> whatever...
> >>
> >> Does this sound like it'd be possible to make it work at all?  If
> >> not,  why
> >> not?
> >>
> >
> >
> > It'll work.  I built a few variations on this idea in the late 
> '70's.> My favorite was a unit I dubbed the "Uglifier" -- it had a 
> distortion> section consisting of a Craig Anderton Ring Modulator 
> (from the first
> > edition of EPFM) and a Craig Anderton Octave Doubling Fuzz with 
> a pot
> > mixing the two signals; a tracking section consisting of a 4046 PLL
> > with a 4024 7-stage divider in the feedback loop, with the
> > divide-by-32 output going back to the comparator input of the 
> PLL, and
> > mixing pots giving combinations of 1 and 2 octaves up and 1 and 2
> > octaves down; and a second tracking section using a 4046 and a 50240
> > top octave divider in the feedback loop, with a switch selecting the
> > top or bottom C as the comparator input (for an octave of notes 
> below> or above the input tone, respectively) and two rotary switches
> > selecting which two of the twelve tones would join the mess at the
> > output.  Played a trumpet through this thing --- horribly lovely.
> > Still have it around someplace; have to fire it up sometime.
> >
> > Tried using an old PMOS organ chip in the feedback loop too.
> > Overheated quite a bit at the time but it worked.  If I ever dig out
> > the chip I'll try again.
> >
> > Had an idea a few years ago for a stompbox version of it similar to
> > the Anderton Roctave Divider, but never got around to building it.
> >
> > But, yeah, it'll work.  The input conditioning is the hardest 
> part....>
> >
> >
> > Paul Camann
> 
>