Integrated Amp Reviews

In July 2000, I reviewed the Mark Levinson company's first integrated amplifier, the No.383, and found that its sound had "clarity, transparency, liquid mids and highs, with dynamic contrasts." Also evident were the No.383's power-output limitations, the result of building large power supplies and heatsinks into a single case that had to fulfill multiple functions. Still, the No.383's price of $5900 was much less than the total cost of the equivalent in Mark Levinson separates. Later, in April 2007, I reviewed a similarly powered integrated amplifier, Bryston's B100-DA ($3195), which included a built-in DAC.

Since July 2000, Class A and B of Stereophile's "Recommended Components" have swollen from 17 to a total of 29 integrated amplifiers. The April 2015 edition of the list shows prices of most integrateds (with the exception of Bel Canto Design's Black system) to be lower than those of comparable component audio systems, and ranging from $3300 to $14,000. Integrateds have continued to be popular in these pages. Within the last 12 months alone, we have reviewed and recommended nine integrated amplifiers—three including built-in DACs—ranging in price from $799 to $50,000, in weight from 2.9 to 77 lbs, and in power output from 22 to 300Wpc.

At the 2015 Consumer Electronics Show, the Harman Luxury Audio Group introduced a new Mark Levinson integrated amplifier, the No.585, designed to be compatible with present-day multichannel surround systems and to handle digital signals with an internal, DSD-capable DAC—and managed by a sophisticated and intuitive user interface. When an opportunity arose to review the No.585, I jumped.

What's New
The Mark Levinson No.585 delivers 200Wpc into 8 ohms, provides 6 digital inputs, and sells for $12,000—double the No.383 in all three parameters. New to the '585 are its line-level outputs, its digital-to-analog converter that handles both PCM and DSD digital music files, and is equipped with Harman International's proprietary Clari-Fi circuit for reconstructing compressed digital audio files. The exterior heatsinks of its predecessor have given way to a combination of internal heatsinks and vents in the top and bottom plates, and the new amp's exterior is further streamlined by leaving off the No.383's rear handles. The No.585 is 0.31" narrower, 0.35" taller, and 2.8" deeper—but only 7 lbs heavier—than the No.383. (Even so, the No.585 is Mark Levinson's lightest amplifier.)

Controls & Input/Output Interface
The No.585 resembles Mark Levinson's flagship stereo preamplifier, the No.52 Reference Preamplifier. A Standby button is centrally placed, low on the faceplate. In standby mode, all circuits up to the output stage remain powered, shortening warm-up time and lengthening average component life. Two large knobs—Input on the left, Volume on the right—flank the display and the other controls. Just below the display is a row of pushbuttons; from left to right, these are Polarity, Setup, Enter (for saving setup changes), Display Intensity, Balance, and Mute. These switches are duplicated in the No.585's slim, well-balanced remote-control handset. Also on the remote are buttons for controlling USB playback functions—Play, Pause, Fast-Forward, Fast-Back—and enabling the DAC's Clari-Fi feature.

On the No.585's rear panel are three rows of input connectors, flanked by a stereo pair of speaker connectors with "hurricane" knobs (so named for their similarity to the hurricane symbols seen on weather maps). The top row of connectors is devoted to analog signals, the middle row to digital, and the bottom row to the No.585's control functions. The analog connectors include a pair of RCA line-level outputs, three RCA inputs, and one pair of Swiss-made XLR inputs. The line-level output connectors can be set as fixed or variable, the latter setting optimal for driving a powered subwoofer(s). An internal 80Hz, second-order high-pass filter can be configured and activated through the No.585's menu system, to filter audio sent to the main speakers, while the line-level subwoofer outputs remain full range.

The row of digital connectors comprises one AES/EBU, two S/PDIF coax, two optical, and one asynchronous USB Type B. In the bottom row are an Ethernet port, a 3.5mm minijack for an external infrared receiver module, an RS-232 (RJ-11) port, a USB Type A socket, and trigger input/output connectors for a 12V trigger signal to turn the No.585 on and off. Just to the right side of this bottom row is a combination AC mains socket and power switch.

Conservative Design Philosophy
Todd Eichenbaum, director of engineering for Harman's Luxury Audio Group, explained that the No.585 was the first commercial consumer product entirely designed by the 12-person team at Mark Levinson's new facility in Shelton, Connecticut, where all listening tests and QC checks are also performed. Manufacturing is done at Mack Technologies, in Westford, Massachusetts, which has the capacity to track every circuit board and its level of revision, and organize these data into an easily retrievable database for continuing quality control and service needs.

The ML design team prioritized those functions that directly affected the No.585's purity of sound quality, and excluded such things as a headphone jack, a record/monitor loop, and a phono stage—the last omitted because it would have required expensive low-level circuitry and additional shielding. Rather than exotic PCB dielectrics, such as those used in the No.52 preamplifier and No.53 power amp, the No.585 has FR-4 glass-epoxy PCBs with gold-finished traces, at a fraction of the former's cost. While its audio circuits use military-spec thin-film or tantalum-nitride resistors at key points, the No.585 does not have large, expensive capacitors—all audio circuits are direct-coupled.

The design of the No.585's power supplies follows this approach: One small supply handles housekeeping functions when the integrated amplifier is in standby; another provides power for all digital and control circuits. Separate secondary windings from a single 900VA toroidal power transformer power the left and right line-level analog circuits and the left and right power-amp channels. Having separate sets of secondary windings effectively separates the left and right channels from each other in the same way that separate transformers do. In addition, one channel's windings can "borrow" unused capacity from the other as needed. The line-level power supplies for the left and right channels employ linear regulators, which isolate them from AC mains fluctuations or demands from the amplifier channels.

Construction
The No.585 is built on a chassis of steel and aluminum. The amplifier circuits are mounted on internal heatsinks, with openings in the bottom and top plates to vent heat without the need for fans. The circuit boards are mounted horizontally in evenly spaced layers using a card-cage architecture, in which each function is implemented on a separate circuit board; these boards include ones for the preamplifier, the DAC, and digital input processing (USB). This approach isolates the low-level analog and digital circuits from the power supplies and amplifier modules.

Eichenbaum designed the two-channel line-level preamplifier, which incorporates fully discrete, mirror-imaged, dual-mono analog circuits, with individual signal-switching relays for each of the four stereo inputs: one XLR, three RCA. Volume controls employ discrete, 15-bit, R-2R ladders and low-noise analog switches. The gain-level offset function in the No.585's setup menu allows the user to establish the optimal volume level for each input.

An option new to Mark Levinson integrateds is the No.585's built-in DAC. Its USB audio receiver is based on a C-Media 6632A processor, which is fully specified up to 32-bit 192kHz PCM and DSD256. (Eichenbaum adds, "We have not evaluated it at 384kHz or DSD512; it may or may not work at one or both of those.") The DAC itself, based on a 32-bit ESS 9018K2M Sabre D/A chip, is paired with a discrete current-to-voltage converter, an antialiasing filter, and a proprietary jitter-rejection circuit. The No.585's menu lets the user pick one of three different filter characteristics for digital streams with PCM content: Fast rolloff, Slow rolloff, or Minimum Phase impulse response. There's also the above-mentioned Clari-Fi algorithm, which, according to the owner's manual, "analyzes compressed digital audio files during playback and reconstructs much of what was lost in the compression process." The circuit's software-based Intensity control, available via either the amp's setup menu or a dedicated button on the remote handset, adjusts the amount of reconstruction applied to the signal.