[sdiy] 566

[jbv]

> On Tue, Jan 27, 2004 at 05:03:51PM +0100, jbv 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...

Thank you all for your comments about the 566.

I'll sure buy that book by Thomas Henry (don't know when I'll find
the time to read it though).

What I have in mind is similar to what Tom Arnold describes (quoted
below) : to have a bunch of small cheap VCOs.
I'm still exploring the granular world, and would like to complete a
few projects using analog VCOs. Only signals would be analog, all
VCs (including expo converter) would be handled by a uC and a simple
S&H. That would no doubt drop the total amount of parts needed...
Furthermore, the 8 pin DIP package of that chip is very attractive in
terms of PCB room...
Actually, my question about using it in a bank of VCOs concerned rather
the sound quality of the output waveforms (has anyone any experience
with it ?) and the drawback of having some VCOs in parallel "locking"
their frequency in an expected way...

Any other problem that might arise (and didn't cross my mind yet) in such
a project would be much apreciated...

Thanks again,
JB

>
>
> If you get the Midwest Analog booklet about the 566 it has about everything
> you'd need to make a tolerable VCO.
> Some thoughts : 1. He points out it goes a little flat across its range and
> sure enough it does.  Maybe some more tweaking could even that out, but it
> will increase the partscount.  2. By the time you do make it wide range it
> starts to get sorta high in the parts count catagory anyway.
>
> Once I get to it, I'm going to build a few VCOs just to have them around,
> but I'm not going to go crazy building them like I had planned.  I'm more
> going to use them for various "weird" things that come up, like drum voices
> ( also Thomas Henry designs ) and the like, and go for 4069 based VCOs
> because they are insanely cheap and simple to make.
>
> I've been specifically looking at the building lots of small cheap VCOs for
> a project.  I have a board layout mostly done for a 8 voice 4069 VCO board
> which I'll build 8 of.  Long story why, maybe I'll get it done enough to
> talk about. :-)
>
> --
>  ------------------------------------------------------------------------
>  - Tom Arnold -       When I was small, I was in love,                  -
>  - Sysabend   -       In love with everything.                          -
>  - CareTaker  -       And now there's only you...                       -
>  --------------         -- Thomas Dolby, "Cloudburst At Shingle Street" -