Hi,
If you're looking to build the formant then I would advise you to try and find these parts before you start. ua726 paired transistors as this supplies the control current for the VCO it is very important. I've been looking for some time and haven't found any. Not to worry though as there is a new book called Formant MSS2000 .... Be warned it is in German Language.... I have bought a copy of this book and am currently looking at building the upto date VCO. The components are easier to get hold of and most of the theory behind them is the same.
Find your electronic copy of the manual here:
http://www.ftg.co.uk/studio/dl/
So far I have simulated every circuit in the original book except 24db VCF and RCF on a program called Tina. This has allowed me to see what happens with the circuits and over the next couple of months I will be constructing the PCB's, Which are being made within my University.
If you can get a hold of the components by all means try and build the original but if not then MSS2000 should be considered. I'm working with the two books as I don't speak a word of German and I am able to see where the differences are my only worry is the calibration procedures.
New to MY formant.
Inclusion of the MidiJack which costs $100 with free shipping and should be easily incorporated into the design.
Next Stage after build -- Include a microcontroller within each module to allow programming, this will include changing the pots to Digital control and digitasl switches.
Let me know how you get on
Cheers
Kris Bishop