A Two Transistor Sine Wave Oscillator

This is an interesting circuit:

source: https://www.edn.com/a-two-transistor-sine-wave-oscillator

It works OK:

but I didn't have much luck keying it:

The make isn't too thumpy but the break is clicky.  I just put in a 4.7K ohm emitter resistor on Q1 which stops oscillation.  A key closure shorting that emitter resistor will key the circuit (I also put in a series .56 uF cap) but the weird thing is that the minimum key time is kinda long.  There are probably other ways to key it but if things get too complicated it defeats the point of a simple circuit.

The Peltz oscillator keyed better:

https://wb9kzy.blogspot.com/2024/11/the-peltz-oscillator-again-as-shaped-cpo.html

But it's an LC oscillator and the frequency is not easily changed - you can't have everything !

I'll keep looking - one of these days I'll find a simple circuit that keys nicely for a CPO and is better than my previous efforts.

One other thing to explore might be using this basic multiple feedback bandpass filter circuit as an actual discrete transistor filter (rather than with op amps).

Best Regards,
Chuck, WB9KZY
http://wb9kzy.com/ham.htm