Etalon Sound writes: "Our philosophy says a low frequency amplifier should be only balanced. Here we comment in brief. A normal (unbalanced) signal is transmitted by two conductors. One is a signal conductor, the other is a ground one. This signaling method is different by implementation simplicity, but it cannot withstand interferences. In contrast, a balanced signal uses three conductors: two signal conductors (direct and inverse), and one ground. As the result of subtracting from the direct signal of the inverse one, the phase interferences, induced on such a line, are compensated, and the useful signal is increased in amplitude twice. That is why a balanced connection has two main advantages: the ability to transmit signals over long distances (200 meters or more) and increased interferences immunity. These features of the balanced connection explain its use in professional and consumer audio equipment of high class.

A third advantage is much less known: balanced circuit can significantly reduce the harmonic distortion (due to the compensation of even harmonics). In a properly assembled balanced amplifier circuit harmonics can be reduced of 10, and using specially selected elements - up to 100 times!

We know, that many manufacturers use a symmetric XLR interface. However, upon closer inspection, it often turns out that it is rather a formality. And the components, declared to be balanced, substantially are not. The existence of balanced inputs and outputs does not guarantee that the scheme located within is balanced. Rather often after the input the signal is converted from balanced to unbalanced, amplified or somehow still treated by the asymmetric circuit and before the output is converted again - from unbalanced to balanced. As a result, this approach negates all the advantages of a balanced circuit design.

It should be noted that not only amplifiers, but all components, manufactured by Etalon Sound - DAC, Phono stage and others - are of balanced circuit. And the principle of the balanced analog converter circuit starts with the digital part, which is extremely rare."