Mark Levinson No. 360S D/A Converter

A 35-pound black box that made a several-thousand-dollar converter survive the format wars.

Overview

The first thing you notice about the No. 360S is not the sound. It's the styling. Audio (June 1999, p.70) called it a "black box with boredom." The reviewer conceded that the large controls and displays read cleanly from across the room, then added that this was "one case where inner beauty compensates for a lack of surface charm." The chassis is a plain, functional slab. The reason people paid for it is inside.

Inside is a forward-looking digital design. The 360S doesn't just convert - it's built to be re-taught. Madrigal's design uses four Analog Devices SHARC 32-bit digital signal processors to run proprietary digital filtering, decode HDCD, and carry enough headroom to handle whatever DVD-based "super audio" formats emerged later. The digital interface receiver ahead of those DSPs has wide enough bandwidth to accept signals faster than any current DVD-based source could deliver, and it's programmable through an RS-232 port.

The conversion itself is dual-differential, 24-bit, with Burr-Brown PCM 1704 multibit DACs - two matched devices per channel - taking the balanced digital signal to analog. The 360S hand-trims bulk-metal-foil resistors to match gain, where the plainer 360 uses a hand-trimmed Vishay pot. It also keeps the four-layer cyanate-ester circuit boards from the earlier 36S, which Madrigal credits with clean power-, ground-, and signal-path routing. A second-generation Intelligent FIFO system buffers and reclocks incoming digital audio to knock down jitter, and low-voltage differential signal drivers carry the balanced digital stream from the processing board to the audio boards.

The measured numbers are good. THD is rated at 0.0035% at 1 kHz and 0 dBFS, A-weighted. Frequency response runs 10 Hz to 20 kHz, +0, −0.2 dB, with SMPTE intermodulation distortion under 0.005%. Dynamic range is better than 100 dB, signal-to-noise better than 105 dB, channel separation better than 110 dB. Low-level linearity shows no measurable deviation to below −80 dBFS and no more than 1 dB down below −90 dBFS. Output impedance is specified under 6 ohms, which means long cable runs into virtually anything without drama.

Connectivity is unusually complete for a converter. There are six digital inputs: two XLR (AES/EBU balanced), one RCA coaxial, one BNC coaxial, one ST-type optical, and one EIAJ-type Toslink optical. There's a mini-jack for an infrared repeater, an RJ-45 PHASTLink communications port, and an RS-232 port on an RJ-11 connector. Outputs include a pair each of balanced XLR and RCA analog, a digital XLR, plus separate RJ-45 ports for PHASTLink and Mark Levinson Linking Master. The 360S can accept any standard sampling rate and word length up to 96-kHz/24-bit. The hardware is designed so it can be programmed to decode 192-kHz signals and proposed formats like Meridian Lossless Packing or Sony/Philips Direct Stream Digital.

The unit weighs 35 pounds, in a chassis the review measured at roughly 15¾ by 3¾ by 14 inches. The master power supply sits in a steel sub-enclosure to contain low-frequency electromagnetic noise. Two transformers separate digital from analog circuits, with separate secondary windings on the analog transformer to improve channel separation. One gripe: the AC cord plugs in from the underside to minimize 60 Hz noise. That's annoying in practice, as the reviewer admitted, though he called a minor flaw essential to define even the best work of art as human. Line voltage is factory-set for 100, 120, 220, 230, or 240 volts, with line frequency set for 50 or 60 Hz.

Audio (June 1999, p.71) called the 360S the most up-to-date and advanced D/A converter the reviewer had tested to that point. He praised transparency, musical information, and neutrality as good as he'd heard from any converter, with extraordinarily natural dynamics and bass detail. His comparison put it ahead of his upgraded Theta DS Pro Generation V on transparency, transient response, and crisp dynamics, and he judged it a rival to the far more expensive dCS Elgar. He also noted it extracted the best from old and poor-quality CDs.

At $6,995 the 360S undercut the older Levinson No. 30.5, which had sold for nearly $16,000, and the reviewer argued it actually outperformed it. The plainer No. 360 offered much of the same technology and upgradability for $4,495. Owners of a No. 36 or 36S could have theirs upgraded to 360S spec for $3,500 or $2,500 respectively. The architecture was built to be reprogrammed, and the connectors and DSP headroom are there to do it.

The reviewer found the AES/EBU connection less interconnect-sensitive than S/PDIF coaxial and cleaner than optical, and recommended balanced cabling into a truly balanced preamp and amp for the signal-to-noise gain. He also flagged that the 360S was not compatible with his Theta transports. He warned that most DVD players claiming 96-kHz/24-bit output don't actually deliver it, though Pioneer's DV-505 and DV-606D could pass a genuine high-resolution signal.

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