[sdiy] 566

[Scott Gravenhorst]

jbv <jbv.silences at club-internet.fr> wrote:
>> Do you mean the 556 (dual timer)?  566 is anything but cheap
>> now that it's transmuted into an isotope of unobtainium.
>
>I really mean the 566...
>A few months ago I got 40 pcs on ebay for less than $30...
>

Ok, "cheap" for you then.  Well, sure, it would work that way.
 But if you want each one to track an expo CV, you need expo
converters for each one (or lots of good sample and hold
circuits with one expo converter and the driving logic).

If you don't care about voltage control, i.e., just a bank of
oscillators each with a frequency pot, then the 556 dual timer
actually makes more sense, depending on exactly what the
intended use is.  If it were me, I would not use the rare 566
for non VC applications.  Also, if you decide to use the 556
(dual timer), there may be problems with soft synch, especially
between oscillators on the same chip.  There may be a CMOS
version of the 556 which would be somewhat better.  If not,
there's always the 7555.

I gave up on finding the 566, it's a single chip tri/square
VCO, which is something that can be done fairly easily in other
ways.  LM13600/LM13700 and I assume other dual OTAs as well can
also be a one chip solution.

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