[sdiy] Ridiculously PC (Phase Correct)

[Magnus Danielson]

Hi!

A while back we had a discussion on phase correct oscillators.

We then discussed the building of a phase correct oscillator based on
a triangle core. As I was looking into just one such oscillator this
evening (actually just the schematics, but who cares) I saw that it
indeed is phase correct. So, there is commercially made phase correct
VCOs, and the winner is: Buchla 259!

Anyone interested in the details can pick the schematics of my site.

The 208, the Music Easle, is not phase correct however, it's
squarewave is 90 degree of, straigth from the core.

The 258 is not phase correct either.

There is a very good reason for the 259 to be phase correct, namely
that it needs it for it's... Hrm... extensive timbre processing and
mixing. It takes the best of two separate sheets in the shematic
(sheet 3 and 4 BTW). The lovely and crazy thing about the 259 is that
the whole mixing is CV controllable. It just sits there waiting for
you to sweep and LFO over its somewhat more unusual timbre processing.

This VCO pair is worth studying.

Cheers,
Magnus