the critical current-to-voltage conversion stage with dedicated operational amplifiers possessing superlative rise time and band- width characteristics. Each channel incorpo- rates two of these DACs in a dual-mono mode configuration. Following this, a custom active filter circuit sums both halves of the balanced signal and provides excellent com- mon mode noise rejection in addition to its outstanding audio characteristics. This approach to the digital-to-analog circuit topol- ogy yields extraordinarily low distortion, improved signal-to-noise ratio and superb, musical sound quality.
Following the active filters, the signal passes through the volume control. The Nº51 vol- ume control is built around a dual MDAC 12- bit ladder attenuator, derived from the Nº40. Volume controls are a critical part of any audio product, and multi-channel audio is particularly demanding. Offsets in volume level between channels can be large, yet always need to be maintained in a precise relationship over the entire control range. The Nº51 volume control uses a hybrid ana- log/digital attenuation scheme to achieve a remarkable 100dB control range at 0.1dB res- olution for the entire range. By applying DSP
based digital attenuation only to fill in the gaps for the very lowest level volume control steps, we do not suffer the loss of resolution associated with pure digital volume controls.
For music reproduction, the Nº51 offers sep- arate, fully balanced front left and right out- puts in addition to a 5.1-channel output. Additional attention was given to these chan- nels resulting in a design which maintains fully balanced signals from the digital-to-ana- log conversion stage to the output.
C o n c l u s i o n
The Nº51 represents the next step in the evo- lution of the Mark Levinson product line. It combines superb video and audio perform- ance while remaining true to the core princi- ples of Mark Levinson. It is designed to ele- vate the enjoyment of DVD-Videos and CDs to a remarkably high level. New features, such as HDMI, allow the stunning video quality of the Nº51 to be appreciated, while the tried and true analog audio circuitry make it a remarkably musical product. The Nº51 Media Player owner can take pride in knowing that they have purchased the finest instrument available for the enjoyment of their film and music collections.
