This 4-transistor amplifier can work from 4.5 or 6 V power supplies. We found it in a Mullard transistors manual from 1960. The transistors are from the time.
This circuit was obtained in a manual of the used old operational amplifier. However, the same...
Other series amplifiers such as the MC3301, MC3401 and LM2900 can be used on this circuit. We...
The circuit is from an 80's publication, but the components are current, only special type diodes...