What impacts the total harmonic distortion in an amplifier?

The total harmonic distortion (THD) in an amplifier is primarily influenced by the design of the amplifier circuit itself. This is because the circuit design determines how the amplifier processes the input signal, including how it handles nonlinearities and transients which can introduce harmonics into the output signal.

A well-designed amplifier circuit can minimize the introduction of distortion by carefully selecting components and configurations that maintain linearity across the intended operating range. Features such as feedback, negative feedback, and the choice of transistors or operational amplifiers all play critical roles in shaping how faithfully the amplifier reproduces the input signal.

In contrast, while aspects like the power supply quality, cooling system efficiency, and output impedance can affect performance, they do not fundamentally change the internal operational characteristics of the amplifier like the circuit design does. For instance, a poor power supply can lead to noise but does not inherently determine THD levels, making circuit design the pivotal factor in controlling distortion.