MX Series Source Equipment

At the heart of the MXC7000i is a 24-bit precision multi-bit Δ-Σ (delta-sigma), 192kHz dual differential Digital-to-Analogue Converter (DAC). This DAC has an exceptionally wide dynamic range and very low distortion. More significantly, its integral switched-capacitor output filter greatly reduces its sensitivity to clock jitter. In order to achieve the ultimate in low-jitter performance, the MXC7000i uses a specially selected high quality crystal-controlled master clock run from its own isolated low-noise power supply.

The four output signals from the DAC feed two differential low-pass filters using an individual low-noise ultra-high-speed Difet operational amplifier for each channel – together with precision 0.1% metal film resistors and 1% polypropylene film capacitors. These precision op-amps filter out the high-frequency energy from the DAC without corrupting the delicate audio signal. The signal then passes to the discrete output stage featuring Myryad’s Double Complementary Cross-Coupled configuration (DC3) operating in Class A from high voltage power supplies.

All the audio stages in the MXC7000i are DC-coupled to ensure the most accurate signal path. Any residual DC on the output is trimmed out by manual adjustment of each channel during production. The alternative approach, using a DC servo, introduces additional active and passive components into the audio signal chain, and so always produces some degradation of the audio signal, however small. Myryad’s trimmed DC offset technique eliminates this degradation and results in a significant improvement in sound quality.

The power supplies in the MXC7000i have received particular attention. Two separate toroidal mains transformers are used, one dedicated solely to the audio circuitry to ensure total isolation of digital and CD servo noise from the audio signal. In addition, the audio supplies have 20,000 μF of reservoir capacitance to ensure the cleanest possible source for the analogue supply regulators. Even the digital/transport supplies have 10,000 μF of reservoir capacitance. All the power supplies use high-speed rectifier diodes to minimise switching noise. The MXC7000i has a total of 14 separate regulated power supplies, each designed specifically for its individual application. The isolation of the most critical power supplies exceeds 130 dB.