With only 1% distortion, this Motorola amplifier found in a 1968 documentation makes use of period components. The frequency response ranges from 10 Hz to 100 kHz.
The presented circuit is suggested by Texas Instruments (www.ti.com) in its Application Report...
This circuit has the muting action delayed by the action of C5. The circuit is from the SGS linear...
This circuit from a 1970s General Electric publication applies to motors of the series winding type....