This circuit is from an old American documentation and its use in motorcycles with 12 V is suggested to power 6V radios. The transistor can be the BD136 and BC548.
We found this configuration in a documentation for radio amateurs from 1974. The circuit can be...
Texas Instruments' low power operational amplifiers OPAx196 can be found on Mouser Electronics....
This low power amplifier circuit for speaker or phone is from the Philips Databook of 1990. The...