Amplification: an apparent effect

Energy is not created, it can only change form, and amplification, in hi-fi as elsewhere, is only an apparent effect, it is what we perceive when we use it.

But how it really works ?

What we commonly call an amplifier is actually a modulator: we apply a small signal at the input and find it at the output “amplified,” that is, increased in one of its components (voltage or current amplifier), or both (power amplifier).

What happens in reality is that the input signal merely modulates the energy supplied by the power supply: that is, the supply voltage and current are modified by the input signal, resulting in an output signal that is broader and more or less faithful to the original one, depending on the quality of the MODULATION carried out and the ability of the POWER SUPPLY to deliver the energy required by the modulator at all times.

The power supply then provides all the necessary energy, which is modulated by the input signal and transferred to the load. What we find at the output of the amplifier, from a quantitative point of view, is nothing more than the product of the input signal and the amplification ratio (gain), while from a qualitative point of view, it is the combination of 3 elements: the quality of the input signal, which is related to the source; the quality of the modulation, which depends on the circuit solution and the components used; and the quality of the power supply. The final result consists of the product of these 3 components, each of which appears equally decisive.

The importance of POWER SUPPLY in a quality system.

THE POWER SUPPLY is the source of ENERGY for an amplifier, which cannot function without it.
In addition to the quantitative sizing necessary to ensure the operation of the amplifier itself, consideration must be given to the qualitative aspects of the power supply, which depend on a multitude of factors including the speed and accuracy with which it supplies power to the circuit, its sensitivity to upstream power grid disturbances, and the level of noise generated within it and inevitably transferred downstream.

A high-end class power supply must be able to supply the exact amount of power required by the amplifier at any given moment, without ever being a limitation or even a source of disturbance, noise or distortion.

We could say, in summary, that no amplifier can “sound” better than its own power supply.