Pre/Power Amplifiers

It may seem bizarre to design a low-distortion mains voltage supply and then stir distortion back into it but PS Audio has a long history of offering alternative output waveforms with its regenerators. The claim for 'MultiWave' – which adds third harmonic distortion at 150Hz to flat-top the output waveform – is that this increases power supply conduction time and thereby reduces voltage rail ripple in downstream equipment. Whatever the truth and extent of that (I've never seen it tested) it makes the point that low distortion in a regenerator's output may not be the prime requirement. Freedom from mains-borne interference and lowered source impedance may well be the more critical factors. Similarly, neither is PS Audio's 'CleanWave' function about waveform distortion but residual magnetisation of transformer cores, which can occur as a result of AC supply interruption (switching off not at a zero-crossing point). In mains grid transformers this is neutralised using alternating polarity DC of progressively decreasing amplitude; in CleanWave, a high frequency AC signal is added to the output waveform and reduced in amplitude over a five-second cycle.