Found in a 1990s Popular Electronics, this circuit uses a small transformer matched to the impedance of the speaker being driven.
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...