The No390S is the successor to the No39 CD Processor and delivers a remarkable improvement in sonic performance over the original design. The No390S features a complete redesign of the No39 Digital-to-Analog Converter (DAC) and Analog Output Module. Borrowing heavily from the design of No40 Media Console and No32 Reference Preamplifier, the No390S incorporates our latest advances in DAC design, output buffer and volume control technologies, all implemented on a four-layer Arlon® circuit board.

Fully Balanced Design

The No390S is fully balanced in both the analog and digital domains. Information from the disc and single-ended digital inputs are immediately converted to balanced signals and routed to balanced DACs by a Low Voltage Differential Signal receiving circuit. This design technique, borrowed from Mark Levinson digital processors, incorporates our Closed Loop Jitter ReductionTM technology to preserve the precise timing of the digital audio signal.

A four-layer Arlon® printed circuit board provides the foundation for the critical analog audio circuit. First used in the No32 Reference Preamplifier, this material offers superb dielectric properties and helps the No390S achieve remarkable perform- ance with complex, low-level audio signals.

Design of the fully balanced DAC/analog output module follows the Mark Levinson tradition of rigorous component selection. An unusual hybrid design approach incorporating both advanced surface-mount and “through-hole” technologies, allows us to utilize the optimum part at each loca-

Advanced Digital Filter Techniques

Just as with Mark Levinson Digital Audio Processors, the No390S incorporates advanced digital filter techniques carefully chosen to opti- mize the sonic performance of its on-board digital processor. Whether playing a CD, or decoding a digital signal received through an auxiliary input, sample depth is increased to 24 bits and sample rate increased to 352.8kHz or 384kHz (input rate dependent) before conversion to an analog signal. This sophisticated processing of the digital signal before conversion (often referred to as “upconver- sion,” “upsampling,” or “oversampling”) is a fundamental contributor to the excellent sound achieved by all Mark Levinson digital processors. The No390S confirms its internal conversion rate on its front panel display each time a disc is loaded, or an auxiliary input is chosen and locked.

The No390S also incorporates High Definition Compatible Digital® (HDCD) decoding to take full advantage of the resolution available from HDCD- encoded 16-bit CDs. By encoding information more efficiently within the 16-bit space available on the disc, the HDCD format retains more of the resolution inherent in modern high-resolution recordings.

Digital-to-Analog Conversion

Digital-to-analog conversion within the No390S features a Mark Levinson-developed, balanced implementation of a high-performance DAC. This multi-bit Sigma/Delta DAC device delivers superb technical performance. In addition to its unusual multi-bit architecture and unlike typical Sigma/ Delta devices, this DAC has a differential current output stage, which allows us to optimize the critical current-to-voltage conversion stage with dedi- cated operational amplifiers possessing superlative rise time and bandwidth characteristics. Following this, an active analog filter circuit, implemented in a differential amplifier, sums both halves of the balanced signal and provides superb common mode noise rejection in addition to outstanding filtering.