Denon ASD-51W iPod Dock (TAS 213)

Equipment report
Music servers and computer audio
Denon ASD-51W iPod Dock
Denon ASD-51W iPod Dock (TAS 213)

A reader recently wrote in to complain that TAS reviews overuse the phrase, “(Component X) performs like units costing many times its price.” Whether you agree with that sentiment or not, I can assure you that this will not be one of those reviews.

The Design

Like the groundbreaking Wadia 170i before it, the Denon ASD-51W is a dock that can tap into an iPod’s native digital stream. This bypasses the iPod’s chintzy internal DAC in the interest of superior sound. But that is only the start of this clever device’s capabilities. The ASD will also play Internet Radio stations, as well as music from Napster and Rhapsody, all without the assistance of a PC. Further, if there is a computer handy, the Denon will happily stream its music files to your system. In this way, the ASD serves as a kind of digital gateway for a whole array of digital source material.

The problems surface in the ASD’s execution, and by that I refer to both its sound and operation. But first comes an installation process, which, due to this unit’s versatility, could have easily caused consternation. Instead, setting up the Denon is a snap. Connect its output to an analog linestage or a DAC, then string an S-video cable to the nearest TV since the unit has no front panel for a user interface. At this point, the Denon will play tunes from an iPod. Track navigation is accomplished using the flimsy plastic wafer of a remote, but both it and the nested menu interface prove perfectly serviceable. The display helpfully shows track and album information, elapsed time, and cover art.

If you are also interested in streaming music from the Internet or a PC, one additional connection is needed between the ASD and a router. This can be either wireless or Ethernet. Either way, most of the ensuing setup, other than entering a wireless password, if appropriate, takes place automatically so long as the router supports DHCP, which most do.

Resets, I’ve Had a Few

Before moving on to the sound, a few cautionary words are in order regarding the ASD’s operation. Simply put, this proved to be one flaky unit. Once, the video feed unaccountably became a feast of squiggly yellow lines. I resolved the issue using the tried-and-true technique for all computer-based gear: a reboot. In the Denon’s case, that means powering down, unplugging it for a few seconds, then reconnecting AC and powering back up. Voilà! Video restored.

On another occasion, I was listening to my iPod when suddenly, mid-song, the Denon’s audio morphed into a loud hum. Neither the ASD nor my iPod would respond to commands. Some anxious moments ensued as I fretted over my fairly new iPod, but all was resolved by rebooting both devices.

There was one other time when I could not get the dock to connect to my router no matter what I tried. This prompted a call to Denon’s technical support desk, which guided me through a “hard reset.” That worked, but it also wiped out all my previously saved settings and station favorites. I will say, though, that the unit had no further glitches after that operation.

The Sound

I approached the sound of the ASD in stages, intending to work my way up from the lowest to the highest fidelity source material. Consequently, I began by listening to a smattering of Internet Radio stations, with resolutions that varied from 32kbps to 128kbps of highly compressed MP3. My expectations for sound quality were low, and they were fully met. Although tonally the Denon’s Internet Radio was more extended on top than I had anticipated, in dynamics and resolution the music was a featureless, noise-ridden wasteland. Still, Internet Radio through the Denon is perfectly fine for its intended role as background music.

I had higher hopes for the higher-resolution material on my iPod. The ASD won’t do the really high-res stuff, but it does support up to 48kHz. Before playing the iPod through the Denon’s digital output, I took a cursory listen to the analog out. In this mode, the iPod’s inferior DAC is replaced by one of apparently similar quality within the ASD. I say that because the Denon’s analog output sounded dreadful. The haunting and lovely “Enchanting Ghost” from Sufjan Stevens’ little-known All Delighted People EP, for instance, became sonically pale and emotionally unmoving. Neither bass nor dynamics existed in any meaningful way. Meanwhile the Beatle-esque “Faust Arp” on Radiohead’s In Rainbows, which normally offers very realistic acoustic guitars, natural vocals, and sweet orchestral strings, sounded as if Thom Yorke were singing through a blanket, and the orchestral instruments were scoured of all their individuality. Then, the fabulous percussion on the follow-up track, “Reckoner,” lost all its sparkle and drive.

But this dock’s claim to fame is its digital output, which bypasses not only the iPod’s internal DAC, but the Denon’s as well. Using a good coax cable, I plugged this output into a dCS Debussy. If the ASD was ever going to sound good, this was its best shot. And, indeed, it sounded…better. Through its digital out, the Denon rendered pianos more richly; bass made a modest comeback, and so did dynamics. In this mode, “Faust Arp” no longer sounded sickly, and the percussive flourishes on “Reckoner” came through much more clearly. On “Enchanting Ghost,” the subdued banjo and electric guitar lines became audible for the first time.

However, “better” is still not necessarily “good.” Even in this mode, the ASD disappointed by never truly breaking out of its mono-dynamic, monochromatic mold. Comparing it to a good CD transport only revealed the wealth of important information the ASD was leaving behind. My reference deck, for example, fleshed out instruments much more fully, and its bass had a solidity the Denon never approached. In addition, the reference’s dynamics were hugely more dramatic than the Denon’s. When you add all these losses together, you end up with sound that is neither aurally nor musically engaging. Indeed, while listening to this dock, I often found my mind wandering.

Still, can any iPod dock match a reference-caliber CD transport? Yes, it can, as I learned when I swapped out the Denon for the less versatile but similarly priced Wadia 170i. The difference was simply staggering. Folks, these two products are in entirely different leagues. On quieter pieces, like “Enchanting Ghost,” the 170i’s ability to convey subtle phrasing makes all the difference in the world, rendering the song once more beautiful and affecting. Through the Wadia, the strings on “Faust Arp” revealed their individual character, while percussion on “Reckoner” fairly sprang from the speakers and drove on from there. Finally, when the bass entered later in this track, it did so with an authority that contrasted starkly with the Denon’s limp lows.

Most importantly, my attention never wandered as I listened to the Wadia; my focus stayed effortlessly and unwaveringly on the music. This is the hallmark and the benchmark of all high-end-audio components. Unfortunately, for all its promise, the Denon ASD-51W simply does not clear that bar.


Outputs: Stereo single-ended analog, coax digital
Other connections: Ethernet
Dimensions: 5.5" x 1.5" x 4.25"
Weight: 11 oz.
Price: $299

100 Corporate Drive
Mahwah, N.J. 07430

Featured Articles