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piglet

On 12/12/2020 6:19 pm, wrote:
On Sat, 12 Dec 2020 17:54:08 -0000 (UTC), "Don" wrote:

In sci.electronics.design wrote:
On Sat, 12 Dec 2020 07:56:15 -0000 (UTC), "Don" wrote:

Phil Allison wrote:

the Callins is in an epoxy sealed container

Interesting, but it doesn't answer my question:

Why was the circuit designed to use a Callins in C7?

Was it designed that way?

That circuit was barely designed at all. What's it supposed to do?

Your question restates the gist of this thread.

How can you know the circuit was barely designed at all if you don't
even know what's it supposed to do?

Because it's full of trimpots and selected values. It was probably
futzed until it worked. What's it supposed to do?

My guess is it was some kind of analog synth VCO, inputs EFG are summed
and make the ramp, square and triwave outputs at jacks HDJ.

Dig the 3.6V D3 zener in the path, the 3.9Meg and 680R R19 R20 and the
kooky voltage follower Q3 Q11 Q4 - the unijunction Q2 is probably the
least nasty part of it all.

Thats why I used the word unsavoury!

piglet