[sdiy] EMS VCS3 VCO

[Grant Richter]

> Q59 & Q60 - CV input op-amp with Q61 & Q63 for expo-responce.
> 
> The current charges the capacitor and Q64 & Q65 buffers and amplifies the
> signal. Q67 & Q68 forms the schmittrigger amplifier and Q62 is the feedback
> transistor.

You can not run a current source (like expo transistor collector) directly
into a capacitor. Start up transient is infinite and stalls simulation. Put
a resistor of some milliohms between transistor collector and cap.

PC Traces, solder joints and component leads are milliohm resistors (with
some inductance and parasitic capacitance too) between EVERY component in
EVERY circuit in the real world. If you really simulated something, every
wire, trace and interconnect would have to be a component model.

The map is not the territory.