250 mW audio amplifier

How it works

This low-power design connects its 1.8 kΩ resistor to the output node rather than directly to the positive supply. That connection influences the stage’s operating conditions and feedback behavior.

The archive estimates an output of about 250 mW into an 8 Ω speaker. This is a small-signal listening circuit rather than a room-filling amplifier, and its useful output depends on the supply and distortion limit.

On the bench

Measure the quiescent voltages before connecting the speaker. Increase the input gradually and watch for clipping; use the archived component values as the starting point.

Resources & provenance

Rewritten from the original circuits/aum/lj3on1t_aum014.php page. Component values and historical performance claims have not been independently bench-tested. The circuit figures have had their watermarks removed.