So I'm trying my hand at some basic CMOS synth stuff and I've run into some basic questions in all the reading I'm doing.
Take the Beavis heterodyne space explorer schem:
1) What is the reason for the 1.5k resistor in series with the 10k/100k pot? I'm assuming to always have a resistance of 1.5 k min there between 1 and 2...but why? And why that value?
2) What is the necessity of the mixing diode or resistor? I tried two oscillators from the 40106 w/o any mixing resistors and the sound barely changed much. And why that value resistor?
3) Why is C5 there at all?
4) In general, what is the basis for deciding on particular pot values in a circuit like this? I get why between 1 and 2 on the 40106 -- i.e., frequency, but why say 100k for volume over 50k?
5) FINALLY, why are there no decoupling caps here?
Phew...that's a lot of questions.