AW: Transcendent Polysynth

[Haible Juergen]

	>I use four of the voice cards with an
	>appropiate power supply for a polysynth, driven from a Design
Labs PROLOGUE
	>midi-CV box. It sounds very nice, especially with each VCO
having a
	>separate LFO for PWM and vibrato. 

Sounds impressive - Congrats !

	>The VCF is based around two halves of
	>LM13600. Do these sound different to a LM13700? 

If you don't use the internal buffer (darlington) stages, they are
exactly
the same.
The buffers stages, however, are different. The 13700 buffers have
rather
high impedance (but still rather low for accurate tracking of low
frequencies),
the 13600's are rather low impedance from the start, but the impedance
is
tracking with the ota's bias current.

	>Oh yes, the other great thing about the Tim Orr polysynth, is
that it has
	>no fancy digital hardware for its keyboard interface. Just 74
chips and a
	>couple of SRAMs. No midi mind, but it can control 1,2,4 or 8
channels of CV
	>and gate.

I *love* keyboard interfaces that are built from standard MSI chips !
(Just played for an hour on my OB 4-voice keyboard clone yesterday ...)

What exactly is this "Tim Orr Polysynth" ? 
I'd love to see documents for this one !

	JH.
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