vco8 (Axxe VCO)

[tomg]

Yeah but I'm thinking tempco the npn-expo tranny or stuff the
whole thing in a 3096 and tempco the chip if I have to. I really 
would like to keep it all transistor if I can. ( you know ..all-tranny
synth?) On the bench finger-heat on the schmitt trigger-pair had 
no effect but the freq went right up (just a little) when I grabbed 
the npn-expo? 

The way I see it, it's a pnp adder, npn expo, charge cap, 
fet follower, schmitt trigger, reset fet. The resistors from reset 
to the expo are for hi-scale comp. What do you think?

(BTW) change the 0.01 to 0.027 for better low-freq range. I
might be getting more and more off center.. It makes me very
happy listening to this oscillator? I don't know why it just makes
feel good?

Most of the saw oscillators I've seen distort (a little reset garbage)
the wave on the lower side, this one distorts on top...I dunno what
that means but I like it...;-)

Tom

> >Hey Juergen, are you still looking for that simple yet stable vco
> >for the 32 oscillator poly? I may have stumbled over something
> >you want.....It's the vco from the Arp Axxe. It's not quite as
> simple
> >as the unijunction vco1 as a matter of fact it's about twice as 
> >complicated as the vco1 but it uses common fets.
> 
> Hi Tom,
> 
> it looks pretty much like a 1st version Odyssey VCO.
> In the Odyssey, the two NPNs of the schmitt trigger are
> part of a transistor array in order to have temperature compensation
> of the trigger threshold.
> 
> JH.
>