Cambridge Audio Azur 651C Black

Azur 651C, 20Hz - 20kHz, 115dB, 25W, 4.8kg Twin Wolfson WM8742 DACs deliver a significant performance upgrade over the 651C's award-winning predecessor and are implemented in a dual differential configuration (each channel has its own DAC to process information). A sophisticated Two-Pole Dual Differential Double Virtual Earth Balanced Bessel filter configuration rejects virtually all noise and distortion present in the DACs and filters them to produce an unprecedented level of performance.

The new DACs also feature a selectable digital filter with three settings to suit your own listening preferences and of course your own system:

The Steep roll-off filter exhibits strong attenuation of aliasing images outside the pass band (i.e. above 22.05kHz) at the expense of a little pre and post-ringing in the time domain.
The Linear phase filter uniquely features, constant group delay' which delays all audio signals at all frequencies by the same amount meaning all audio is fully time-coherent at the output.
Minimum phase meanwhile does not feature constant group delay but rather the co-efficients have been optimised without feed-forward so that the impulse response exhibits no pre-ringing in the time domain.