Buchla Card 6

Card 6 is the Modulation Oscillator. There is one jumper wire. I matched the two 2N3565 NPN transistors with Ian Fritz circuit. Kassutronics has also a good article about this matching method. I managed to match these transistors within 0.5mV (Vbe). There are a couple of resistors that needs to be determined empirically. I changed R5 from 190k to 82k to tune MO to 1V/oct. I also changed R9 from 240k to 330k to rise the MO base frequency. When I calibrate MO I can see if these values are ok. The uA726 is replaced with my mA726 PCB.

Matching 2N3565 transistors.