Digital Processor Reviews

There's home cooking on one side of the hedge and fast food on the other, and the world moves farther from the former and nearer to the latter with each passing day. So it goes in domestic audio, where virtually every new milestone of the past quarter-century has pointed far more toward convenience than toward quality.

Depressed? Don't be. Those of us in the perfectionist community have a history of dealing with such things, howsoever slowly and inefficiently. (footnote 1). We're getting better at it, too, year by year. An example: Chord Electronics, of sunny southern England, has now brought to market their Chordette Gem D/A converter ($799) which they offer as an affordable means of getting perfectionist-quality sound from computer-music files.

From that introduction, one would assume the Chordette Gem is a USB D/A converter. It is, but that's only half the story. The Gem is also a Bluetooth-compatible wireless DAC, intended specifically for use with Apple's iPhone, recent-spec iPods, and the like. In fact, judging from Chord's promotional material, the Chordette Gem's ability to receive digital audio data within a Bluetooth-powered piconet is the product's major reason for being. I guess convenience means never having to reach farther than your shirt pocket for your favorite records.

Description
The Chordette Gem is the same width and depth as an eyeglass case, and just a bit taller—a great deal harder, too, being machined from aluminum alloy. That smooth surface is disturbed by only a very few things: On the Gem's rear panel, working from left to right, one finds a threaded connector for the 4.5" Bluetooth antenna (included); a DC input socket for the Gem's 12V wall-wart power supply (included); a two-position switch for selecting between Bluetooth and USB datastreams; a USB socket; and a pair of gold-plated RCA output jacks. None of these is labeled, which presents a problem only with the aforementioned toggle switch; then again, one always has a 50% chance of getting it right—and the consequences of getting it wrong are mild.

Inside the Chordette Gem is an abundance of surface-mount parts, plus a Cirrus Logic 192kHz receiver, a Sipex 3222 transceiver, an NXP (Philips) microcontroller, and a Texas Instruments PCM2704 USB DAC—all alongside what I assume to be Chord's proprietary digital filter, concealed by an attractive aluminum plate. (Chord is one of the few companies in perfectionist audio that can claim to have designed its own digital filter: a technically impressive FPGA, the development of which led to the company's sonically successful DAC 64 D/A converter.) As for casework, the Gem's single PCB is securely mounted to a characteristically chunky, well-made alloy enclosure, which mixes straight lines and subtle curves to achieve an attractive final product. (It's interesting to note that Chord's founder and chief designer, John Franks, cites among his influences the Spanish architect Antoni Gaud°.)

And like the aforementioned DAC 64, the Chordette Gem has a neat magnifying glass built into its top plate that provides a view of the illuminated circuit board directly beneath. It may remind filmgoers of the porthole built into the chest of the literate but poorly assembled Frankenstein's monster created for the lovably over-the-top Van Helsing. Or it may not.

Installation and setup
Outside the Chordette Gem, perfectionist-quality Bluetooth D/A converters are rare ducks. In fact, as far as I know, there's just this one—so I had to bring myself up to speed on the whole Bluetooth thing in order to write about the Gem. (I confess, I had no idea what the word Bluetooth meant until May 2010, when I bought a new Volkswagen Tiguan and learned that it has a built-in Bluetooth receiver, for hands-free cell-phone use. I've come to love that.)

In order to stream music to the Chordette Gem, I needed only to power up my 32GB Apple iPod Touch (v.4.0.2), select the icon for Settings, then select from the ensuing menus the choices for General and, ultimately, Bluetooth. Typing in the password "0000" brought me to the Choices menu, in which appeared the single line "Chordette 1523." I tapped it, and all was made right. (During later forays, I wasn't required to remember that less-than-cryptic password, though I did have to repeat all those other steps. Oh, the drudgery.) The Apple iPod is considered an SRC (for source) in the terminology of the multi-corporation engineering consortium that governs all things Bluetooth. The Chordette Gem is thus an SNK (for sink). (I can't for the life of me imagine why computer geeks aren't content to use normal English words such as transmitter and receiver. For their part, they probably can't imagine why high-end audio geeks use such words as macrodynamics and dimensionality when they're talking about drama and presence.)

Readying my system for the USB half of the Gem's capabilities was also a simple matter of making a few software selections, this time in the System Preferences window of my Apple iMac. As perfectionist hardware goes, the Chordette Gem was itself less than inscrutable: The only tasks required were to remove it from its (very nice) carton, connect the USB input cables and analog audio output cables, and connect the rather typical wall wart—after which I could see its guts glowing amber-green through its porthole. Success.

I was surprised that the Chordette Gem is supplied without an owner's manual. (The hint about the password was printed on a label affixed to the carton.) Nor could I find a .pdf file for a Gem manual, or any other products in the Chordette series, on Chord's otherwise comprehensive website. No big deal—but a manual might have saved me some time and aggravation by explaining that this SNK can't be found by its SRC unless its two-position toggle switch is in the Bluetooth position. Which, again, isn't labeled . . .

Listening
Since my experience with other USB D/A converters was ample and my experience with Bluetooth SNKs nil, I began auditioning the Chordette Gem in the former mode, playing AIFF and WAV files (and the occasional MP3) from my Apple iMac (OS 10.6.2, iTunes 9.2.1) with the aid of a Transparent Performance USB cable.

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Footnote 1: I persist in considering the Naim CDS the first good-sounding CD player in history, although it arrived on the scene a full eight years after the medium's introduction, and sold for the considerable sum of $5000 (in 1991 money).