We found this configuration in a 1990 Poptronics. The circuit can be powered by voltages between 6 and 15 V, changing the resistors in series with the LED. The frequency is set at R7.
This amplifier was suggested by the Texas Instruments linear applications manual of the 90s....
This circuit appears elsewhere on the site. The circuit shown is from an American 1980s...
We found this circuit in Texas Instruments' Linear Circuits Applications. In the original it is...