This very low power amplifier is designed by Amperex for hearing aids. It is based on TAA370 which is not an integrated circuit that can be found today.
We found this circuit in Sperimentare magazine number 4 of 1977. The magazine no longer exists, but...
The circuit presented is from the Linear Applications Handbook of the National Semiconductor of...
This 5 V power supply for TTL circuits was found in an article that taught how to assemble a test...