[sdiy] Modifying the SEM/Kobol VCO to not need that +18 V supply

[Aaron Lanterman]

Consider the Mark Verbos variant of the Kobol OSC schematic:

http://www.simple-answer.com/kobolosc.pdf

Could we get away with setting a lower reset point by using a  
different voltage than the rail at the emitter of the 3906 and the top  
of the 470 ohm resistor just to the left? So the TL082 wouldn't need  
to swing so far at the top? (Along those lines, if a LM329 will give  
me a nice 6.9V reference, will stacking two of them give me a nice  
13.8 V reference? Hmmm, that's probably outside of what a TL08x could  
swing with +/- 15 V supplies, so we'd probably need something else).

It seems that you wouldn't necessarily need to mess with the threshold  
value use by the comparitor.

- Aaron