HRT Music Streamer+ USB D/A Converter Follow-Up, December 2010

Art Dudley wrote about the HRT Music Streamer II+ in December 2010 (Vol.33 No.12):

Consumer audio hasn't enjoyed many success stories in recent years, so this one stands out: According to distributor Elite Audio/Video, their USB-based Music Streamer D/A converters, designed and built in California by High Resolution Technologies, have been kicking ass, taking names, and generally scaring the hell out of everyone else who wants a share of the computer-music market.

But the Metamucil of technology doesn't settle in the bottom of the glass for very long, especially when audio reviewers are doing all the stirring. (Stereophile thrives only by sowing discontent among hapless consumers. I read that on the Internet, so it must be true.) Thus the folks at High Resolution Technologies (HRT) have been busy in the two years since they introduced the Music Streamer ($99) and Music Streamer+ ($299) USB D/A converters. In August 2010, the Music Streamer II ($150) and Music Streamer II+ ($350) arrived.

Except for their slightly different logos, the new models look exactly like their predecessors: 4"-long (Streamer II) and 5"-long (Streamer II+) boxes of hexagonal cross-section, made of aluminum alloy and painted red or gray. The boxes are all but featureless, having only a USB jack at one end and a stereo pair of RCA jacks at the other. Neither wall warts nor DC-in jacks are needed—the Music Streamers get all the power they need from the USB bus itself.

Inside, the most obvious difference between the old and new models is the use of a single PCB in each instead of a motherboard with a smaller plug-in (as before). However, designer Kevin Halverson says that the differences are many, including a thoroughly redesigned power supply along with newer and presumably better USB transceivers, D/A chips, and other bits. Indeed, I spotted a high performance TI TAS 1020 chip among the various subminiature imponderables in both new models. (The earlier models had used the resolution-limited Burr-Brown PCM2706 transceiver chip.) The new Streamers are claimed to handle sampling rates up to 96kHz and word lengths of up to 24 bits. Further, Halverson says the new models will always play music files at their native resolutions, with no attempted upsampling of lower bit rates and word lengths.

Like the originals, the new Music Streamers were easy to install and to use. They powered up automatically when connected to an active USB bus, becoming very slightly warm to the touch over the course of several minutes. Proprietary software identified each HRT converter for the host computer—in this case, a recent-vintage Apple iMac—after which output-device selection was performed onscreen in a matter of seconds. For audiophiles, such as I, who use Apple iTunes without benefit of a software plug-in such as Pure Music (see Stereophile, August 2010) or Amarra, it's also necessary to adapt to each distinct file type by exiting iTunes, opening the computer's Audio MIDI utility, and selecting the appropriate sampling rate before reactivating iTunes.

The Music Streamer II+, the first of the new models to grace my system after I'd briefly reacquainted myself with its predecessor (sloth has its advantages), retained the HRT house sound: slightly dry, with a little less openness and body than with the exponentially more expensive DACs from Ayre Acoustics and Wavelength Audio, but with notable musical momentum and flow, especially for such an affordable product. From there, the II+ improved on the original in a variety of ways. Notwithstanding some enduring dryness, the new HRT had distinctly more saturated tonal colors, with especially notable gains in the sounds of woodwinds, brasses, and voices.

The II+ also sounded much bigger—the smallish group in Daniel Myssyk's brilliant interpretation of Hindemith's Escales Romantique, from Fidelio Musique (at present, this superb recording is available only on a limited-edition Fidelio sampler), seemed to stretch in every direction—and like a much more dramatic, more dynamically nuanced device. On Live at the Linda (ripped from Dreadnought CD 0701), David Grier's mid-1940s Martin D-28 sounded notably richer through the II+: more like its very complex vintage self. The result, in plain English, was a realer, incontrovertibly more involving sound. The improvements wrought in the HRT II+ were no less evident on standard-issue pop. The songs on Joanna Newsom's richly arranged Ys (ripped from Drag City DC303CD) gained in that same way: They, too, were richer, with more color, corpus, and human subtlety.—Art Dudley

High Resolution Technologies, LLC
1027 N. Orange Drive
Los Angeles, CA 90038
(323) 967-7447