Suboctave generator - 4013?

[Theo]

From: Tony Allgood <oakley at techrepairs.freeserve.co.uk>
<snip>
> This maybe because of the less than fast rise time
> at the clock input (don't believe this bit), or because set-up times are
> not being met.

You may not believe this bit, but it might just be the problem.
I had similar problems a view weeks ago with a 4017.
It turned out that some manufactures use Schmitt trigger input stages (e.g.
On semi) allowing unlimited risetimes,
while others (like fairchild) don't and need a minimum rise time of 5us
@15V.

I had a Schmitt tr. gate left over in an other part of the circuit, so I put
it in front of the clock.

Theo