[sdiy] Circuit queries

[Pat Kammerer]

Hi all,

Hope someone can enlighten me a bit.  Thanks in advance!

Considering the following circuit;
http://home.swipnet.se/cfmd/synths/schematics/freqdoubler2.pdf

I'm seeing very nice square/rectangle waves at the output of this circuit,
in ralation to pretty much any periodic input.  Judging by the label on the
schem, I would guess that this should not be happening (am I correct?)  I
did make some changes to the values just to experiment.  I really like the
sound, even though it seems not to work right, but it would be interesting
to find out whats going on with it.

And considering the following VCA schematic;
http://www-timc.imag.fr/Yves.Usson/personnel/SDIY/images/VCA-US1.pdf

Can anyone help me understand what I should be seeing at the CV summing
stage.  I see it's inverting, so theoretically the output should be
negative, or is this amp expecting negative control voltages?  I do get a
negative output, but both inputs are at ground.  I've check the input and
feedback resistors, and the soldering and continuity are solid, but still no
voltage is present.  The output only MINUTELY changes with change of the
input.  Is this anything like what should be happening?  I get no CV control
of gain by inserting voltage at the CV input.  One put changes the overall
gain a bit, but the other seems to do nothing at all.

Thanks if anyone can help out!
Pat