You used 2n3904/6 on the breadboard?

 

Yup

 

Its not only 2n3904/6 many BJTs dont work on LTSPICE for this oscillator.

 

Wont work with 2n3904/6 efficiency isn't an issue for this.

That circuit won't work without the buffer either.

It works with a redesign to give a properly operating sawtooth circuit by inverting the bottom transistor and separating the current-mirror circuit from the threshold circuit (why did you change the circuit from post #34?).
It has an output offset of about 200mV.

 

That circuit won't work without the buffer either.

It works with a redesign to give a properly operating sawtooth circuit by inverting the bottom transistor and separating the current-mirror circuit from the threshold circuit (why did you change the circuit from post #34?).
It has an output offset of about 200mV.

View attachment 184831

Thanks for the modification, it works really well. It even remains almost undistorted to very fast frequencies.

Can this circuit still be made to oscillate 8hz to =>80khz?

This would give it very adjustablewith a 20 turn potentiometer .

 

Can this circuit still be made to oscillate 8hz to =>80khz?

A 10,000 to 1 frequency range is generally to much for one range.
You could do it by using a pot and switch in different capacitors to say, give a 10:1 frequency range for each cap.
That would require switching among 1 of 4 caps.
Would that be acceptable?

 

In post #45 the bottom 2N3904 is upside down.

 

Quick fix, prevent the NPN from saturating: