Looking for more gain for use with SA612/LM386 receivers, I found this version by JF1OZL. *
Emacs!
Bread-boarded it and did some basic measurements with the feedback resistor Rf at 10 Ohms
With a bench supply voltage of 9V and at a frequency of 1 kHz, got the following results.
Input: 0.00275 Vpp** output voltage was 7 Vpp across a 7.5 Ohm 5W resistor, about 800 mW.
That calculated to ~69 dB (Data sheet is 43 dB)
The output looked clean with no apparent spurious stuff.
* Also another version from LA3ZA which used a few more parts.
** At 9V supply, the output starts clipping above this value from the function generator
