Buchla Barberpole

[StephenGiles]

The Model 297 Infinite Phase Shifter displaces the phase of an applied signal by up to 1800 degrees, depending on frequency and number of stages selected. The phase shifted signal may be combined with the original to create a moderately warped comb filter with complimentary outputs. Notch density and depth can be varied through feedback (resonance) and stage selection. A wide range sweep oscillator enables the familiar cyclical phase shift effect.

All parameters (phase shift, notch depth, sweep rate, sweep depth, resonance) are voltage controlled, with processing control inputs where appropriate. A built-in envelope follower facilitates the creation of amplitude-dependent effects.

The 297 is capable of "barber pole" phasing, with the phase shift (and the consequent filter peaks and notches) continuously moving in one direction. Unique circuitry provides (or consumes) the extra time involved in this process. The rate of change can be varied up to 2.5 octaves per second in either direction and is voltage controllable.

The 297 is a single panel unit 200 series module designed to be installed in a 200 series cabinet and powered with a 200 series supply.
(+5 volts, +15 volts, -15 volts)

A limited number of 297's have been produced and are available for purchase from the manufacturer. Price is $1500; delivery time is about two weeks.
BLOODY HELL!

[mattv]

That's about $1498 more than I have to spare...

What's the most 'mysterious' part of this design, the barberpole?

[puretube]

quadrature outputs LFO...

[mattv]

:idea:  

[petemoore]

That means it's "Tuff"?
 :Quadrature"...as in 'duplicity', or is that an exponent of the complexity?

[StephenGiles]

All is explained here:
http://machines.hyperreal.org/manufacturers/Paia/images/shepard.txt

[puretube]

basically, "quadrature" signals mean 2 signals with phase difference of 90degrees, (0 and 90 deg.) i.e. sin/cos.
(if you invert the sin and the cos, you additionally get the 180 and the 270 degree signal).

[Mark Hammer]

All is explained here:
http://machines.hyperreal.org/manufacturers/Paia/images/shepard.txt

I scanned the article and posted it on my site some time back.  The text in the version Steve linked to is more legible but what I have posted also includes the figures, so that may augment one's understanding.  It would appear that the site is down for the moment, but whenit comes back up, you can find the article about 3 pages in at http://hammer.ampage.org

[petemoore]

Barberpole...I bet that's one mind bending illusion.
 The description makes it seem like a visual hallucianation, as represented in audio...PDneat... :lol:
 [Bad analogy..tracking the bug on the ceiling, that's really a spot]
 Anyone actuall build a working model of this technology? Are there popular records with this effect 'pronouncedly' used on them?
 The article got into 'terms of endearment' that are new and unknown to me. Terminology I didn't understand.
  Probably over my head at this point,,,I'm not going to try perfing it...