EPFM project, CA9 Ring Modulator, kit updates, t&s

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EPFM project, CA9 Ring Modulator, kit updates, t&s

Post by PAiA-Scott »


Without blathering on too much. I'd like to first state that I'm a huge fan of Paia. I own a 9730 VCF, a MIDI to CV frac unit, and a 2700/4700 system that I'm in the process of restoring.

Anyway, I bought an unassembled 2002 version of the Paia CA9 Ring/Balanced Modulator kit second hand and I'd like to verify some parts because they do not match up with my 1980 addition of Craig Anderton's Electronic Projects for Musicians (and there was no other documentation included).

Therefore, could you please tell me the values of these parts or if they are still identical to my 1980 version of Craig's book?

C2 (which I know controls the frequency of oscillator one and varies depending upon my preference)

I have a 2.2uf electrolytic, a 33uf electrolytic, a .0047uf disk cap, and some assorted resistors left over.

Thank you for your time. It's appreciated.


Hello David.

I have uploaded the page which relates our kit for the project to what is presented in the Electronic Projects for Musicians book.

The electrolytic capacitors you have are functional equivalents to those specified in the book. You mention a 0.0047, but I wonder if you might be seeing a part with the marking 473. The 47 marking is for 47 000 pF and translating this to uF moves the decimal six places to the left for 0.047uF and this is provided in place of the specified 0.05uF (likely marked 503, for 50 000pF). If not, you should use the specified 0.05 or 0.047 microFarad and not the 0.0047.

For a short time we sent an adapter kit to make a 5532 op-amp work in place of the specified 4739, but then updated the board to use the 5532. Let me know if you have the adapter kit and need the details for it.
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Scott Lee