Friday, May 2, 2008

Chord Choral Blu CD transport & Choral DAC64 digital audio converter

Chord Choral Blu CD transport & Choral DAC64 digital audio converter 
Chord Choral Blu CD transport & Choral DAC64 digital audio converter 
Chord Choral Blu CD transport & Choral DAC64 digital audio converter 
Chord Choral Blu CD transport & Choral DAC64 digital audio converter 
Chord Choral Blu CD transport & Choral DAC64 digital audio converter 
Chord Choral Blu CD transport & Choral DAC64 digital audio converter 
Chord Choral Blu CD transport & Choral DAC64 digital audio converter 
Chord Choral Blu CD transport & Choral DAC64 digital audio converter 
Chord Choral Blu CD transport & Choral DAC64 digital audio converter 
Chord Choral Blu CD transport & Choral DAC64 digital audio converter 
HI-FI, Sterio, Home Theater, Audiophile, Amplifier, Speaker

I was stumbling through the Denver Convention Center at CEDIA 2006 when I spotted John Franks, of Chord Electronics, and Jay Rein, of Chord's US importer, Bluebird Music, stranded in the basement purgatory for "niche" products. I couldn't resist asking, "What sin relegated you guys to this little hell?"

"Practicing two-channel without a license," riposted Rein, before going on to describe Chord's new 6TB Media Engine music server. "But we didn't bring it. We brought—this."

He'd been blocking my view of Chord's table. Now he moved aside and made a flourish toward the Blu, the DAC64, and the 2HIGH, all gleaming there seductively.

My eyes widened. My nostrils flared. I did everything short of snort, paw the ground, and run my trembling hands along these products' well-formed flanks. Gosh, what sexy beasts.

"How . . . how . . . how . . . ," I stammered.

"How much?" Jay asked. "All three components total $17,500."

"No—I mean, how . . . how . . . how . . . " I felt like a teenager asking for the keys to dad's Healey Sprite.

"How do you get to audition one? All you have to do is ask."

What the heck did he think I was trying to do?

I've heard there was a secret chord
The Choral Blu and DAC64 are a wee bit different from other transport-DAC combinations. As part of Chord's Choral series of components, each is a lozenge milled from a solid billet of aluminum and measuring a compact 13.1" W by 4.1" H by 6.6" D. My audition samples came anodized and polished in a deep, lustrous black (15% upcharge).

The top-loading Choral Blu ($10,400) has a large, spring-loaded clamshell disc cover dominating its right third, and an illuminated display set above 25 buttons to its left. Mirroring the Blu's look, the Choral DAC64 ($5000) has a "porthole" lens over one of its circuit boards. To the porthole's left, two arcs of six holes each are bored into the chassis like open parentheses. The Choral 2HIGH rack ($2100) holds the Blu and DAC64 stacked, um, two high—and canted at a 30° angle.

As striking as all this is, it's what's inside that's really fancy. The transport is a Philips CD2 powered by a switch-mode power supply that has its own AC filter. The Blu can upsample digital signals to 88.2kHz or 176.4kHz before sending them to a Watts Transient Aligned (WTA) filter. Chord says it has taken them 20 years to develop the WTA filter—and to figure out why higher sampling rates sound better. "It's not ultrasonic information," said John Franks. "If it was that, then 768kHz recordings could not sound better than 384kHz recordings—there's no information above 200kHz that could even be captured by our recording equipment."

There's a problem with upsampling to 176kHz, however: the S/PDIF pipeline can't accommodate a datastream that dense. Chord solves this by outputting each channel on its own BNC-terminated S/PDIF link. There are also AES/EBU and optical outputs. You can set dither to 16 or 24 bits, and there is a word-clock option, should you happen to have one in your system. (I don't either, but Chord sells a lot of gear to recording studios, so it's there if they need it.) The DAC64 can accept digital signals at 44.1kHz, 88.2kHz, or 176.4kHz. (JA reviewed an earlier version of the DAC64 in July 2002.)

So what are the benefits of high sample rates?

"What we're hearing is better resolution of transient information, which is something that human beings have evolved to being very good at detecting," said Franks. "A sampling rate of 1MHz would be ideal for capturing this, but it can be done at 44.1kHz with digital filtering—as long as you have sufficiently long tap lengths."

Beg pardon?

"Reconstruction filters generally have short tap lengths—the longest manufactured is only about 256 taps. We've constructed field-programmable gate-arrays (FPGA) that are 1024 taps long, which suggested that infinite tap length would produce 'indistinguishably perfect' sound quality. More practically, we developed a WTA filter with a 64-bit DSP core."

But wait, isn't there a WTA filter in the Blu, too? Yup—they built it, they're gonna use it. The DAC64 then sends the signal to a pulse-array DAC, which applies 64-bit seventh-order noise shaping and 2048x oversampling with "improved pulse-width modulation elements."

I was reeling at all the information I was downloading from Franks—my mind needs a bigger buffer.

"We'll get to the buffer, but first I need to expand upon that 64-bit DAC environment," Franks said. "A 16-bit input multiplied by a 16-bit coefficient gives you a 32-bit output. By using a 64-bit filter and architecture we avoid having to throw away information by truncating the output—something that becomes important if a digital volume control is used.

"Now we get to that buffer. Because we use all-digital data extraction, we can employ a RAM buffer to sequentially accept all the data, re-time it, and then output it. It gives us a jitter-free local clock, without requiring us to send a clock signal back to the source device. All of this takes place in Xilinx Virtex FPGAs, which offer 200,000 gates per device."

I must have looked puzzled. Franks had delivered all of this before my second cup of coffee of the day.

"That means we can change the entire design simply by updating the EPROM. It's state-of-the-art now, but if it ever isn't, we have the technology to fix it."

Franks is British. He couldn't have been teasing me by quoting the opening to The Six Million Dollar Man.

It goes like this: the fourth, the fifth
Setting up the Choral Blu-DAC64 combo isn't exactly rocket science, but you do have to take care of a few housekeeping matters—once, and then they're done with. The 2HIGH rack comes in three pieces, which are secured to one another with six bolts. The slots that the Blu and DAC64 slide into are lined with felt; the fit is snug, but there's no metal-to-metal contact.

Because I wanted to use the 176.4kHz link from the transport, I set the Blu's three-position clock switch to the proper setting (down) and connected the transport to the DAC64 with two van den Hul-supplied BNC-terminated S/PDIF cables. I set the DAC64 to receive data from its S/PDIF inputs and set the buffer to maximum (4–5 seconds). I did try the minimum setting (2–3 seconds) and Off buffering settings, but felt the small improvement in solidity and three-dimensionality offered by the maximum buffer was worthwhile—so I went for it.

A note about the jet-black finish: It's gorgeous, but forget about reading the text engraved on all those tiny buttons. Fortunately, everything is recapitulated on the Blu's hefty remote, but even after weeks of use, I found it impossible to remember which button controlled what, other than Play, Stop, Forward, and Back.

I also never cottoned to the "disc interface," at least when it came to removing discs from the well. Putting discs on the spindle was pretty straightforward, but removing them required pressing down on the upmost part of the disc, which tilted it, allowing you to get a finger under its forward lip. It felt awkward, even if it wasn't—and it punctured any fantasy about being pampered by the luxurious Chord kit. In other words, it felt like work.

I wasn't wild about the disc-removal process with the Oppo DV-970 I reviewed in May either, but at $159 I expected an ergonomic glitch or two. Strangely enough, I'm less forgiving at $15k.

Your faith was strong but you needed proof
Attention Screen's Live at Merkin Hall (CD, Stereophile STPH018-2) got a major workout on the Choral system. John Atkinson was mastering it when I first received the Chord combo, and he sent several generations of that my way, as well as the final-production CD as the review period drew to a close. Attention Screen's use of dynamics and tonal shading made it excellent audition material, but two elements kept me coming back for more: the phenomenal sense of space the Chord extracted from the discs, and the rock-solid physicality of the sounds of the instruments.

"Blizzard Limbs" is perhaps the track most filled with silence on Live at Merkin Hall—there's lots of "white space" between the notes—and the song illustrated one of the Chord's best qualities. Musical tones don't have a physical component, of course, but tones don't exist by themselves, except on recordings. In the real world, tones aren't just notes; they're shaped by the vibrational qualities of the instruments that produce them and the spaces in which they're produced. You're not hearing that guitar string, or that snare-drum head, or that piano; what you're hearing are those things amplified by the drum body, or amplifier cabinet, or sounding board as well as the hall they were played in. So while the vibrations themselves don't have a body, they're so influenced by the physical elements that produced and contained them that they do have the presence of something solid.

The Chords got this better than just about any other "Red Book" player I've heard. "Blizzard Limbs" begins with drummer Mark Flynn's rock-solid beat, joined by Don Fiorino's crunchy guitar chords, and finally joined by Chris Jones's Martian fretless bass guitar—all weaving in and out of the Merkin acoustic like threads passing over and under one another in a loom. Bob Reina's piano begins by adding just a little emphasis to phrase endings, before working its way through the warp and weft.

It wasn't reconstruction, however, it was re-creation. It was sonically convincing, not just in timbre and texture, but in its presence.

Oh yeah—and it flat-out rocked.

The title track of Ojos Negros, by Dino Saluzzi and Anja Lechner (CD, ECM 1991), like Live at Merkin Hall, carves long swathes of melody out of silence, but here the dynamic range is less extreme. The notes are not so starkly drawn against the acoustic, but remain very close to its baseline. Many CD players seem to have more trouble delineating such minute dynamic shadings, but not the Blu-DAC64 combo. While clearly delivering the timbral similarities of Saluzzi's bandoneán and Lechner's cello, it did an even better job of celebrating their differences. Because the two musicians delight in mimicking one another's tone and completing each other's phrases, this was especially welcome.

Welcome? No, vital was more like it. And the Chord combo's ability to deliver that life essence made a huge difference between my liking the music and my surrendering completely to its passion.

. . . yes and how he kissed me under the Moorish wall and I thought well as well him as another and then I asked him with my eyes to ask again yes and then he asked me would I yes to say yes my mountain flower and first I put my arms around him yes and drew him down to me so he could feel my breasts all perfume yes and his heart was going like mad and yes I said yes I will Yes.

I think I need a cigarette.

Tierney Sutton's "Sometimes I'm Happy," from her On the Other Side (SACD, Telarc 63650), is far more closely miked than either of the other discs, but engineer Robert Friedrich still captures tons of room detail under Sutton's sexily slurred vocals and Trey Henry's power bass. It's Ray Brinker's crisply moving drums that really grabbed me, however. Such speed, such palpability, such U-R-there-itude! Once again, it wasn't so much about sound, but about sound's body.

But now you never show it to me, do you?
In the May Stereophile I reviewed the Nagra CDP ($15,000), which impressed me as one of the best pure "Red Book" CD players I have ever heard. In both price and intent, it seemed the perfect, um, analog to the Chord Blu-DAC64. Both offer impeccable fit'n'finish; both aspire to the state of the art.

I connected the Nagra and the Chord Choral combo to both my Ayre K-1xe preamplifier and the HeadRoom Max Balanced headphone amp with Shunyata Altair Helix balanced cables. I use AKG's K 701 headphones in balanced mode for headphone comparison. Once again, I praise the Nagra's flexibility: Being able to choose its high-gain option for use with the Ayre and its lower-gain output for the HeadRoom Max Balanced made meaningful comparisons easier.

On Tierney Sutton's "Sometimes I'm Happy," the Nagra CDP revealed a bit more snap in Ray Brinker's brushwork. There was a bit more rat-a-tat-tat and sparkle, although the Chord gave more heft to Trey Henry's loping bass lines. Each player captured one or two things better than the other, but I wouldn't say either convinced me that the other got much wrong.

On "Ojos Negros," however, I felt the Chords better delineated the line between being and nothingness. The sounds of Saluzzi's and Lechner's instruments emerged from the room acoustic more fully formed, more rounded, more three-dimensional.

My listening notes refer consistently to "breath." It was only while attempting to reconcile the idea of "breath" with my impression of sonic palpability that I realized that breath may be only air, but it implies that there's a body somewhere doing the breathing. Holograms don't breathe; bodies do. So did the Chords.

That sense of bulk, heft, presence, or palpability captivated me with the Attention Screen disc as well. The Nagra left nothing out, but the Chord combo simply put more muscle on the skeleton—without sacrificing any suppleness.

The more I listened to the Blu and DAC64, the more they reminded me of something. While pondering On the Other Side and Live at Merkin Hall, I realized what it was: the sound of high-resolution digital, such as the Sutton SACD or the Attention Screen 24-bit/96kHz raw DVD mixes JA had burned for me. So I listened to those discs on my Ayre C-5xe. It might not be a completely fair comparison, but I did wonder how the higher-rez stuff would compare to the full Chord press.

It was impressively close. Through the Ayre, the Sutton disc might have had a shade more liquidity, fewer sharp edges—or maybe not. The SACD and CD were more alike than different. The Ayre pulled a few more dB of subjective dynamic range out of the Attention Screen DVD than the Chord extracted from the production CD. Maybe it was just 0.5dB—the swings seemed wider, but just a bit.

Does this mean that the Chord combo's upsampling, oversampling, reconstructive filtering, buffering, and gate-arraying turned "Red Book" into something better? I can't say—it's possible that the "Red Book" spec really is as close to theoretically perfect as, all those years ago, it was pitched to us as being. If that's the case, I haven't heard anyone get as close to that potential as Chord has in the Choral Blu and DAC64.

Or perhaps with all that shaping, shifting, and prodding, Chord has happened on precisely the right combination of euphonic colorations to compensate for my perceptual deviations from perfect. It strikes me as unlikely—but then it would, wouldn't it? No one thinks of himself as a bad listener any more than anyone thinks of himself as a bad lover.

But it does suggest that the Chords might constitute the universal player so many audiophiles have been waiting for. No, the Choral duo doesn't do SACD or high-sample-rate DVD, but let's face it, not all that many such discs are available to us, whereas we have a quarter century's worth of "Red Book" discs that the Chord components can make sound awfully darned good.

And every breath we drew was Hallelujah!
At $15,400 ($17,500 with stand), the Chord Choral Blu transport and Choral DAC64 digital processor don't comprise the most expensive digital rig I've reviewed, but the price does make me gulp a bit. The fact that I can't afford the Blu-DAC64, however, doesn't make me think them unreasonably expensive. To see these components—and to discuss with John Franks the details of their construction—is to immediately understand that they are handmade to an exactingly high standard.

You know if you're one of those who can afford to buy the Chorals. The question is, should you? Only if you've been looking for a CD player that can justify the last two decades of recording technology. To my mind, the Choral Blu and DAC64 are, together, the CD player we music lovers have long prayed for.


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