TomG's VCF9a

[Dr. Jörg Schmitz]

Hi all,

The last two days I tried to built the TomG's Serge SVF (Band/Low/High).
(It's the VCF9a). Well, the problem is : it doesn't work. I first tried
the PCB, then, after it did not work at all, I built it on a protoboard
with the same result. I used the NE5517N. I tested it, it works. The 071
too.
And voltage supply and everything else was tested a lot of times.
I don't think, that the differences between LM13600 and NE5517 are
responsible
for that (in this application). Am I wrong ?

any ideas ?