NAD M22 V2
Stereo power amplifier
The output stage is only one of several circuits in the amplifier, and each must complement the other to obtain optimal performance. The amp is DC coupled throughout, from input to output, there is no capacitor in the forward signal path. Yet, it has a beneficial 12dB/octave roll-off below 2Hz. It does this using a unique circuit topology that is functionally a forward servo. It is however not a servo in the traditional sense as it does not measure DC at the output and send back a correction signal. Instead part of the input signal is fed to a side chain with a second order low-pass filter. The output of this is subtracted from the forward signal input to the second stage thus rejecting DC.
Clean and Dynamic
The performance of the entire signal path is critically dependent on the power supply; in this case a well regulated, but not too tight, custom switch mode design. This allows maximum dynamic power, very high current yet with very low distortion. Secondary supplies are individually regulated and decoupled at each opamp for lowest possible noise and maximum dynamic range.