|Theta Chroma HDCD D/A Converter|
|Home Theater Accessories Accessories|
|Written by Kim Wilson|
|Tuesday, 01 July 1997|
The advantages of a good digital-to-analog converter (DAC) shouldn't be underestimated. Understanding the importance of the DAC within the audio chain, yields a new level of appreciation for the superior performance capabilities of digital audio.
You've heard the term many times, "Garbage In, Garbage Out." This refers to the concept that the output of an audio signal can be no better than the input signal. Conversely, the ability to perfectly reproduce the original input signal can be compromised at any point along the audio path on the way to the outputs.
The sonic qualities of any digital device are greatly effected by the DAC. The ideal DAC accepts the incoming digital bitstream, converts it back to an analog electronic signal, representing exactly the original waveform, and introduces no noise or timing errors (such as jitter) that would effect the output. There are many fine CD and LD Players on the market with exceptional internal DACs but if you want to improve performance significantly, an external DAC is usually the answer.
The Chroma 396 uses 8x oversampling and an 18-bit external DAC from Theta Digital, a leader in high fidelity digital devices. It is a very simple device and uncomplicated to add to your present system. You take the digital output of your CD Player (or another digital source with a digital output, i.e.: DVD, Laserdisc, Direct TV, DAT, etc.) and plug it into either the coax or optical input on the rear panel of the Chroma. You then run left and right analog cables to the appropriate analog inputs on your processor, preamp or receiver.
If you are fortunate enough to have a processor with balanced inputs, the Chroma can be configured with balanced outputs as an optional feature even though the unit is not a differentially balanced DAC like its bigger brothers the Theta DS Pro Basic IIIa and the Gen Va. The Chroma provides standard S/PDIF coax connections as well as a Toslink fiber optic input. A glass optical input, either AT&T or Laserlinque, is also available as an optional feature.
Chroma's front panel offers a switch for selecting the proper input connection, coax or optical. Another switch reverses the polarity of the device by 180 degrees. As described in the manual, the best way to determine which is the proper orientation for your listening room is to listen for a more defined soundfield and increased bass clarity.
There are two lights, POWER, which is self explanatory and the other is a LOCK light. It illuminates green when it receives a proper digital signal. The Chroma is equipped with the new HDCD circuit and the lock light illuminates orange when it locks onto an HDCD encoded signal.
Listening Test. . . First Impressions
The Chroma has a very smooth and enjoyable sound. Now, to hear the sonic nuances of a piece of equipment like the Chroma, it demands some critical evaluation, so I pulled a large sampling from my library including a few HDCDs. I was really looking forward to road testing this DAC, because it was my first opportunity to hear a decoded HDCD in my personal listening environment and not at a trade show.
I started out with Keiko Matsui's Presence of the Moon from the "Dreamwalk" HDCD. I chose this track for the extreme low bass tones and they were deep, rich and full bodied using the Chroma. The sustain on these low tones was astounding. Without HDCD decoding, these bass tones tend to be excessive and overpowering. The mid-bass was articulate with plenty of presence and clarity. The attack and sustain of the Kyoto was bright without harshness and tonally accurate.
Another HDCD with an amazing amount of bass comes from Paula Cole's "This Fire." On the track, Tiger, the bass rumbles well down to 20 Hz and below. With the Chroma's HDCD circuit in place, there is a precision and articulation on notes you were only feeling before.
Wanting to hear a more highly charged CD, I threw in Live's "Secret Samedhi" and cranked the tune Lakina's Juice. To my surprise the Chroma locked on to an HDCD signal. This was a treat and it turned out to be a great demo for comparing the internal DAC of my Nakamichi CD1 and the Chroma. The grunge sound of the guitar was extremely tight and powerful with more bite from the Chroma and their vocals just popped, jumping outward from the center image. Once again, the bass was strongly effected, producing a strong and dynamic punch.
On the flip side, moving in an entirely different direction, I spun the recently re-released and re-mastered XRCD "88 Basie Street" from the immortal Count Basie and his Orchestra. The track Bluesville was an absolute delight when using the Chroma. The soundfield was exceptional, which has as much to do with the re-mastering process of this classic re-release as the DAC. The orchestra was laid out in front of me just like I was there, able to pinpoint each section of the band down to the individual instruments.
The tonal balance of each instrument was extraordinarily natural, especially the sax, which is too often bright, honky and tinny on other systems. I loved the fat, warm plucky and articulate sound of the stand-up bass fiddle. The volume and impact of the brass accents filled the room with that nice BIG live sound. In general the Chroma exhibited more brilliance and sparkle while the Nakamichi DAC seemed slightly dull and muted in comparison.
For my final test I played some Liszt. Etudes d'Execution Transcendante, performed exquisitely by Kemel Gekic, to be specific. For me the hardest thing to listen to on a tonally imbalanced system is concert piano. I find it usually either soothing and transcendental or unbearably jarring and annoying. The Chroma proved itself worthy when I found myself drifting atop the music. There was no hint of harshness across the mids or high end. Bass notes with the Nak's DAC were boomy and mushy, but defined and articulate with the Chroma. Every note, even the fast runs, were transparent and clear. There was this wonderful resonance and air as each note was able to breathe its natural breath. In every instance, there was just more life to the music when played through the Chroma.
Particularly on bass, it seems that encoded HDCD discs would do well to be properly decoded. Other parts of the mix seem to be less obviously effected by the process. If HDCD becomes more popular among today's recording artists, you will want to have either a CD Player or external DAC with the circuit included to achieve optimum performance.
The Chroma provided forceful dynamics that were strong, deep and had plenty of impact. The micro-dynamics were also delivered with equal precision, intensity and clarity.
High frequency information pops, for a nice clear upper end with excellent transient response. The mids were smooth, without the harshness and edginess often found in this range with lesser DACs. If you are used to that bright over-emphasized mid-range, especially for rock and pop, it may take a little while to get used to the even and balanced qualities of the Chroma. Now if jazz, new age and classical are your thing, the Chroma is very likely the DAC you're been craving, offering one of the smoothest responses across the entire listening range that I have heard.
Priced at $829 (US price) including HDCD decoding and a little less without HDCD, the Chroma is far from inexpensive but it is definitely not at the upper end, falling well into a range of affordability for the more discerning listener.
The only obvious limitation of the Chroma is its two inputs (with an optional third). With so many sources like DVD, Laserdisc, CD transports, CD changers, Direct TV, DAT and others, the Chroma can only spread itself so far in improving your system. More expensive DACs have more inputs and remote switching but for $829 the HDCD Chroma is a strong contender for both music and home theater applications even if you have to eventually invest into two of them as your system grows past 3 digital sources.