Reviews of Attainable Hi-Fi & Home-Theater Equipment

Reviews of Attainable Hi-Fi & Home-Theater Equipment

Arcam Solo rDacGreat BuyArcam, based in Cambridge, England, is a manufacturer of high-end audio gear with a strong track record of innovative electronics, including amplifiers, CD players, and A/V receivers. A look at Arcam’s current product line reveals many models that seem at first glance conventional, but on closer inspection it becomes clear that each has something that makes it unique. One example is the Stealth Mat, used in Arcam CD players to reduce electromagnetic interference -- a detail that other companies often seem to overlook.

My history with Arcam goes back 25 years, to when I was a teen and in the market for my first integrated amplifier. This was my first foray into hi-fi -- I had no clue what to look for. I narrowed down my choice to a Kenwood amp or the simple-looking Arcam Alpha Plus. The Kenwood had a more powerful amplifier section and flashier looks; the Arcam was tiny in comparison, with an understated matte finish, and produced only 35Wpc. But the Arcam sounded better, so I bought it. The Alpha Plus led me, years later, to the Arcam Delta 290, and began my journey into true high fidelity.

The subject of this review is another innovative Arcam product, the Solo rDac. Selling for an affordable $479 USD, this standalone digital-to-analog converter constitutes an attempt to produce better sound than most entry-level components can, for a very low price.


The rDac, one of Arcam’s Solo line of budget products, is a sleek-looking, minimalist device housed in a silvery aluminum case. There’s a small round power switch on the top panel, and four LEDs along the upper front edge. These correspond to the input selected, and are so labeled: USB, Optical, Coax, Wireless. The wireless input was not enabled on my review sample, as the rDac comes in two versions. The wireless model, the Solo rDac KW, has an antenna connection that works with two optional Arcam accessories: the rWand iPod/iPad dongle, and the rWave USB dongle. With the rWand, you can hook up your iPhone, iTouch, or iPad and wirelessly stream audio content to the rDac. The rWave hooks up to a USB port on your computer and allows wireless streaming from your PC or Apple Mac computer.

On the rDac’s rear panel are single connections for coaxial (gold-plated RCA), optical (TosLink), and USB digital inputs. To connect the rDac to your integrated amplifier or preamplifier, the rDac sports a pair of analog gold-plated RCA outputs. There’s also a simple on/off rocker switch. I left the rDac on at all times; it’s smart enough to go to sleep if no signal is detected.

Arcam Solo rDac

Inside, the rDac has the same DAC -- a Wolfson 8741 chipset -- that Arcam uses in all of their CD and Blu-ray players. This multi-bit DAC’s sigma-delta architecture can accept 16- or 24-bit word lengths and up to 192kHz sampling frequency. The USB connection is restricted to a maximum sampling frequency of 96kHz, but the coaxial connection can accept up to 192kHz.

One problem with connecting a computer using any digital connection is jitter -- the introduction of timing errors as the signal is transmitted over a digital connection. Jitter can be especially bad with USB links, with a subsequent loss of fidelity. Whether or not jitter is audible sparks much debate among audiophiles; some argue that the effect of jitter is a smearing of subtle detail, like a veil over the sound.

Arcam has a solution for jitter via USB: licensing asynchronous USB technology from Data Conversion Systems, aka dCS. Arcam has long had a relationship with dCS, having used the latter’s Ring DAC technology in their highly acclaimed Alpha 9 CD player. Asynchronous USB generates a precise clock that controls the timing of the data flow from the source computer, and thereby drastically reduces jitter, per Arcam. This technology has mainly appeared in far more expensive DACs; seeing it in a product costing less than $500 is pretty impressive.


I fed the Solo rDac from the coaxial output of my Oppo BDP-83 Blu-ray player, and connected the Arcam’s RCA analog outputs to the RCA analog inputs of an Anthem MRX500 receiver. Normally I’d connect the Oppo and Anthem via HDMI, completely bypassing the digital-to-analog conversion stage introduced by the Arcam rDac.

When I compared the sound of the rDac connected via coax to the Oppo BDP-83 via HDMI, the difference was noticeable. "Ode to Billy Joe," from Patricia Barber’s Café Blue (CD, Premonition/Blue Note 90760), sounded distinctly darker through the rDac, with bass notes much more powerful; the Oppo via HDMI sounded weaker and lighter by comparison, but with more air, especially around the finger snaps throughout this track. I switched back and forth between these connections, each time making sure to match the volume levels. The rDac definitely sounded different, but I couldn’t conclude with certainty that it sounded better. This might have been attributable to a number of things, such as the resolution of my system, the quality of the Oppo player’s digital output, or the quality of DACs in the Anthem receiver. But if strong bass is your thing, the Arcam rDac will be right up your alley.

The next connection I tried was through the USB input, fed from my Acer laptop computer running Windows 7. I wirelessly streamed music from my network storage device (it sits on a shelf under my receiver) to the laptop, but also ran a USB cable from the Acer to the Solo rDac. If I owned the rDac, I’d buy Arcam’s rWave to get rid of the USB cable and keep my laptop untethered. I used the program VLC Media Player to play my music files.

With this setup, the rDac truly shone, its sound several notches above what I’d expected. Noise levels were very low -- backgrounds were very quiet regardless of the type of music I played. This low noise floor laid a good foundation for the music. I listened to a CD rip of Jakob Dylan’s Women & Country (16/44.1 FLAC, Sony) via my music server; a deep bass drum thumps throughout "Nothing But the Whole Wide World," and the Arcam rDac reproduced it tightly and deeply, my two subwoofers providing a sense of realism that I haven’t experienced through other playback combinations. I can’t be sure if this high level of sound quality could be entirely attributed to the asynchronous USB connection, but it certainly didn’t hurt. It was certainly attributable to the Solo rDac.

Another great thing about the rDac is its ability to handle 24/96 signals; finding an inexpensive playback device to do this is frustrating. I owned an Asus O!Play HDP-R1 media player for just this purpose, but a firmware update obliterated it. Now I use my laptop to play these tracks, which is what I did with the Solo rDac. Listening to "Lucia," by Marta Gomez, from the free HDtracks 96/24 Ultimate Download Experience sampler (24/96 FLAC, HDtracks/Chesky), was a riveting experience. Not only did Gomez’s voice sound wonderfully airy, the background percussion had stunning impact through the Solo rDac.

The Arcam rDac performed admirably even with lower-quality MP3 files. With "Dog Days of Summer," from the Glee soundtrack, the sound quality was several levels higher than those of other DACs I’ve tried -- as smooth and refined as the MP3 file would allow. Bottom line: I can’t think of a better, more cost-effective way of extracting the highest sound quality from MP3s than the Arcam Solo rDac.


Arcam’s Solo rDac has exceeded my expectations for an inexpensive DAC. With a sleek silver-aluminum chassis and a single button on top, it’s a good-looking, easy-to-use audio component. Although I didn’t find that it significantly improved the performance of my Oppo Blu-ray player, its forte was playing music through its USB connection.

As more and more audiophiles move their music collections to network servers, I can’t overstate the importance of external DACs and great-sounding USB connections. The fact that the $479 Arcam Solo rDac has an asynchronous USB connection is to be applauded. More important, the rDac significantly improved the sound quality of the music I have stored on my network server.

Before exploring more expensive options, consider that this $479 gem might be all you really need.

. . . Vince Hanada

Associated Equipment

  • A/V receiver -- Anthem MRX500
  • Speakers -- Axiom Audio Epic 80-800, Monitor Audio Silver RX, Definitive Technology Mythos XTR-50
  • Source -- Oppo BDP-83 Blu-ray player
  • Cables -- Analysis Plus Blue Oval in-wall speaker cable, Analysis Plus Super Sub interconnects
  • Monitor -- Sanyo PLV-Z5 front projector

Arcam Solo rDac Digital-to-Analog Converter
Price: $479 USD.
Warranty: Three years parts and labor.

Pembroke Avenue
Cambridge, England CB5 9PBUK
Phone: (44) (0)1223-203203