Oddy VCO IC

[Joachim Verghese]

Hi there,

Tony Allgood writes:

> However, this was all too much for me, so I got rid of the cludge
> altogether and replaced the IC with a 4011UBE. I am guessing that the
> unbuffered version of the IC is probably similar to the A versions. Am I
> right?

You're absolutely right -- the old Odyssey oscillator makes use of
the analogue properties of the 4011AE, which is why it won't work
properly with the buffered 4011BE. I think this was discussed
at some point on the list -- must have been years ago, though.

Just as a preventive measure, I'd recommend soldering in 15V
unidirectional transzorbs (SA15A, P6KE15A,...) across the
power supply outputs of any ARP synth that still has 4000AE-
series ICs installed -- 15V is the absolute maximum for those
chips.

Best,

-joachim