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    What In the World Is Amplifier Bias?

DEFINITION

A bias is an inclination of one sort or another.

For example, lift up one end of a long board.  Now stuff can roll down it!  Stuff can't roll down a board that isn't biased with an incline.

Amplifier bias is a direct current (DC) of electric charge.  This current keeps flowing around the circuit even when the amp's volume control is reduced to zero.  Like an idling engine or an empty incline, a biased circuit is ready for work but unused.

Vibrating guitar strings produce alternating current (AC) that propagates through the amplifier.  What happens to these wiggly signals depends on the amp's DC bias.

RAMIFICATIONS

Examples of how an amplifier's bias setting can affect a sine-wave signal:

Pure Sine Wave

Wrong Bias causing
Unbalanced Signal Clipping,
producing harsh,
Odd Harmonic Distortion.

Over-bias affecting the
Zero-Crossing point of a
push-pull amp, producing a
musical, Even Harmonic Blip.

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