Wrong about 300k ohm on CV link between VCOs - took out resistor to reinstate pot as 500k, and I think I'll change it for a 1Meg pot!!
Also, from Din Sync's CV mixer design, 100k resistors on inputs (from VCOs) are too big - tried parallel connection with 100k to give 50k, and had much stronger signal. In fact, with the 100k's, the square wave mod does not work - so will try 47k (or even 36k or 25k?!?!).
Also, the polarizing switch was busted, so testing became frustrating. Have to re-do switch!
When polarizing mixer is working, its amazing!
(Note: LM358 was working, but I did try 5532 and it does not like minimum supply voltages!)
Lesson: Get a solderless breadboard, mate!