[sdiy] more pitch shifter thoughts

[harrybissell]

yes iyrc   :^P

H^) harry

rkmoore at memphis.edu wrote:

> 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
> >
> >