What are the requirements for a Phaser LFO ?

[frequencycentral]

What are the requirements for a Phaser LFO ?

Ideal shape?

Recommend me one?

[StephenGiles]

Triangle.........but 250 posts later maybe hypertriangle Really it's down to personal preferences, but most that I've seen are triangle. The EH Polyphase has the facilty for squarewave which to me sounds awful. They would have done better to put out a Barberpole Phaser

[Mark Hammer]

Preferred shape depends on speed and potential depth.  For slow sweeps in a circuit capable of going from very low to very high, a hypertriangular waveform is preferred by the ear.  If the sweep is pretty shallow, it matters much less.  If the sweep is faster than, say, 1.5hz you'll find that many different waveshapes tend to blur into each other and the ear misses the details of the sweep.

That's why I like the LFO on the first Small Stone and adapted the LFO on my Ropez/Ross to mimic it.  The LFO provides a hypertriangular sweep but with the addition of a cap to ground on the output (at the OTA end of the output resistor) it softens the "turnaround" at the high point of the sweep, in a progressive manner.  You get the most hypertriangular sweep at slower speeds and something more akin to a shallower triangular sweep at faster speeds; the faster the speed, the greater the softening.

[frequencycentral]

EDIT: See new thread: http://www.diystompboxes.com/smfforum/index.php?topic=69912.0