LYNGDORF Millennium MkIV

The Lyngdorf Millennium is a fully digital amplifier (more precisely said a ´Class D digitally controlled amplifier´). The amplifier works on a Pulse Width Modulation principle. Practically it means that its output voltage is not continuously adjusted according to the varying voltage on its input as with conventional analogue amplifiers but it is rather described by two switching cycles (like CD format, for example). Simply said, zeros mean that there is voltage on the output stage, ones that there is not. The Pulse Width Modulation tells the circuits how long they should be on or off in their respective status.
Such a solution brings a lot of issues along. First, such a switching behaviour happens in extremely fast manner with sampling frequency of 352,8kHz which is approximately 8x faster than sampling frequency of red-book CD format. You naturally cannot hear such high frequencies but they generate a radiation which has to be screened off not to create unwanted distortions. The Millennium tackles this with a low-pass filter of 2nd order that is set at 60kHz with 12dB roll-off per octave. The filter transforms zeros and ones back to analogue signal for the Millennium’s loudspeaker terminals and represents the end of a fully digital path.
The other trouble is the PWM method itself – it varies the signal on the output but such a signal yields steady voltage and it is not usable for loudness control. A clever solution has been found by varying the voltage of Milennnium’s power supply. In such a set up the amplifier is not really amplifying but only adjusting the loudness of a source (e.g. CD player), so technically it cannot be driven into clipping. The clipping is indeed not known in the world of the Millennium and you can enjoy only the purest signal coming to your loudspeakers. There is one theoretical disadvantage and that is the dependancy on the relative loudness level of the source program material. With the CDs recorded at low volumes you may not (theoretically) get the music loud enough. However, during the part of my life I spent with the Milennium I never encountered such a situation, even with problematic CD’s from 80’s. If your equipment is not placed outdoors or in an empty barn you will never suffer from the ´not loud enough´ effect. Lyngdorf does not recommend to get over 89dB anyway (which is the full output of CD, usually referenced to as 0dB). On the contrary - today’s recording industry is cutting really hot CD’s so one has to be careful not to blow one’s speakers.