Which version of the circuit board did you make? The upper, generic one, or the
lower, specially adapted one for the Casio SK?

If you're using the bottom one, take note that the IC pins 1, 5 and 8 are NOT
connected to the board - bend their pins out horizontally before you put the IC
in the board - Or better yet, always use an IC socket soldered to the board
instead of the IC - then you can just plug it in. In this case make sure pins 1,
5 and 8 of the socket are not connected but bent out horizontally.

The bottom circuit is a little bit cramped and its easy to make a mistake. I
made it that small so it could be fitted inside the SK easily.

Why not try making the generic circuit first? Then at least you can troubleshoot
the 2nd circuit with a working one. Just print out the generic track board
picture on a piece of paper - try and scale it on the printer so that it prints
out at actual size to the components. Now glue the printout to a thin piece of
cardboard, like from a cereal packet. Punch holes with a needle where there are
holes marked on the track.

Thread your component legs through the holes, and bend the legs on the other
side in the shape of the tracks, joining them up with some scrap wire from
cutoffs from components and insulated wire where neccesary. Mount a socket in
the cardboard and solder the wires to join up the socket legs to the components.

It's as easy as that - I do that sort of thing lots and its really easy. Get
that one working, and treat it like an external effects box - put some input and
output jacks on it so you can plug anything into it, and so test it. Plug a lead
into the output jack of the SK and the other end into the filter input, and its
output into an amplifier. Keep the SK volume down low otherwise it will easily
overload the generic filter and cause distortion - that's why I added extra
components to the specific SK circuit to address that issue.

Cheers, graham




--- In CasioSK@yahoogroups.com, "sinne.morgen" <sinne.morgen@...> wrote:
>
> Hello,
>
> I'm trying to build the "Simple VCF" like the tutorial in the filessection.
First I used a AD822 opAmp; had one leftover with only one side working
(normally it is a double opamp). Sounded quite messy... My second try with an
NE5334AN didnt work either.
>
> I put the VCF right before the Volume Dial and I used mostly film caps.
> Am I missing something here (like changing some resistors to another avlue) or
just not able to solder properly?
>
>
> Regards
> Sinne
>