Digital Drive: REVIEW: Art Audio ART DI/O DAC Processors by Todd Krieger

Model:	ART DI/O
Category:	DAC Processors
Suggested Retail Price:	$249
Description:	Compact AtoD/DtoA converter
Manufacturer URL:	Not Available
Manufacturer URL:	Not Available

Review by Todd Krieger on September 01, 2001 at 02:21:39
IP Address: 208.176.168.191

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After receiving the Radio Shack 3400mA power supply, and the fact the unit has logged over 100 hours on the "B" system, I figured the ART DI/O DAC was ready for another shootout on the main system against my reference DAC, the Prism Sound DA-1.
The ART DI/O DAC has become somewhat of a "cult" item, as it has recently been the most-talked-about digital product on AA. The DI/O has both an A/D section and D/A section. The A/D section is for making digital recordings, and will most-likely not be used by the vast majority of audiophiles. The 12AX7 tube did not greatly affect D/A performance, but it does run hot and should be removed, if one does not intend to use the A/D section. The unit is diminutive in size and weighs no more than a couple pounds. This is also the lightest DAC I've ever seen. (This could possibly be installed inside a CD player!) The power supply that came with my unit was the 1300mA "wall wart."
The ART DI/O was used with the G&D Transforms UTP-1 transport and Belden 89108 coaxial digital cable. I used the Calrad Teflon phone-to-RCA adapters at the outputs. The Prism DA-1 was used with the same transport and coax digital cable, and the Luminous Audio Technology AES/EBU digital cable. I used various classical, rock, and jazz tracks, mostly from the albums mentioned below. I played the same tracks on both DACs, level-matched, splitting the A-B "fifty-fifty." (The DI/O was played first half the time, the Prism played first half the time.) Occasionally, I played the "A" DAC a second time.
If the ART DI/O has anything over the Prism DA-1, it's timbral accuracy in the midrange. This DAC reminds me so much of the Timbre Technology TT-1, I'd swear the differences between the DI/O and TT-1 would be extraordinarily close. (Maybe the TT-1 would have an edge in regard to listenability.) There was a palpability in the vocals that the Prism could not match. In fact, with small-scale music, I might even prefer the DI/O to the Prism!! Donald Fagan's voice in "IGY", for example, was more-convincing on the DI/O. The slightly-downward tonal balance makes this DAC very forgiving with brighter recordings... as long as the music doesn't get overly complex.
My initial complaint about the DI/O was a small soundstage which varied with dynamic content, with the stock 1300mA power supply. The Radio Shack 3400 mA supply did improve things somewhat. The stage was considerably wider, the stage was more-stable, and the music was a tad more-open. As others have stated, the polarity of the Radio Shack supply into the mains outlet does affect the sonics. The "incorrect" polarity makes the DI/O sound hard in the upper midrange, ameliorated by turning the plug 180 degrees. I did not notice much difference trying the same thing with the stock supply.
Since the top was slightly truncated, the one thing the DI/O was immune to was fatigue-causing RFI. The DI/O was more compatible with the S/PDIF format than the Prism. The Prism sounded a little "hyperdetailed" with the Belden 89108 coax, where it sounded naturally-extended with the Luminous Audio Technology AES/EBU cable.
Note that the weaknesses with the DI/O are on absolute terms. I did not have a lesser DAC lying around to gauge the weaknesses, but they were mainly subtractive in nature. The stage was wide, but not particularly deep. And even with the Radio Shack supply, it wasn't rock-solid like the Prism. The very top is truncated somewhat. Cymbals don't have the sparkle like with the Prism. (But the Prism brings out the digital "grain" as well, where the DI/O does not.) Ambience cues were not quite as easy to pick out on the DI/O. The left channel was noticeably louder than the right with my particular unit. (I noticed this on the "B" system, but I did not realize it was the DI/O until playing it on the main system.)
The DI/O is more-sensitive to the input digital cable used than most DAC's. The Belden 89108 was the one cable where the Ext Sync. mode produced the best sound, where the x2 mode sounded best with the Bolder and other DIY coax cables I had, including the 1506A and 9209 cables. The x2 mode improved the resolution and HF performance, unless the cable was able to pass a superior signal to the DAC, which the 89108 was able to do.
The DI/O's DAC did not always "lock" when the cable was connected, and power had to be cycled to attain the "lock". In my case, this problem did *not* seem to be cable-dependent, as others have suggested. (The Prism did "lock" every time.) The DI/O on one occasion played "white noise" at near full-output level when I connected the digital cable. In case this happens, be sure the volume is turned down when you connect the digital cable.
The biggest sonic weakness with the ART DI/O relative to the Prism DA-1 was in dynamics, but since I've yet to try a DAC that equalled the Prism here, it would not be a huge weakness, if a weakness at all, compared to other DACs. There is a slight dynamic "splash" or loss of microdynamics, which in certain cases, may make a recording sound "more exciting" than the real thing. The inner detail isn't as good either, and I relate that to dynamics as well. Complex passages lost the sense of "air" that the Prism had. CD audio does not do this well to begin with. The Prism did a better job at extracting the "last bit of detail" off the CD. The congestion with complex passages exacerbated the slight upper midrange glare the DI/O had- Recordings with heavy brass or heavy electric-guitar content may fatigue the listener, in an *analog* sense.
Overall, the fact that I'm camparing this little wonder to one of the best I've ever heard suggests that it would be a giant-killer amongst lesser "expensive" DACs. The ART DI/O has superior midrange performance, and that alone makes it a winner. Whether you're upgrading your CD player (which has an S/PDIF out) or DAC, you should try the ART DI/O before spending more money for what could be a less-satifying product.

Product Weakness: In absolute terms- A tad rolled-off in the frequency extremes. Slight upper midrange glare. Slightly congested with complex passages. Not the last word in microdynamics. Channel balance may be an issue. Requires aftermarket products to maximize performance. Output level could pose a problem with preamps and integrated amps that have a buffer stage before the volume control. Outputs need adapters for use with home audio equipment. The A/D section will not be of use to most audiophiles, and its 12AX7 tube should be removed.
Product Strengths: Has a sense of musicality reminiscent of the Timbre Technology TT-1 DAC. Excellent midrange performance. Forgiving with inexpensive associated equipment. RFI immunity above average. Maybe the best bang-for-the-buck DAC ever conceived.

Associated Equipment for this Review:
Amplifier:	Symfonia Opus 10 Amplifier, Sansui G-901DB Receiver
Preamplifier (or None if Integrated):	Supratek Syrah, Sansui Receiver
Sources (CDP/Turntable):	G&D Transforms UTP-1, Audio Refinement CD Complete (used as transport)
Speakers:	Von Scheweikert Audio VR-4.5 Mod 5, Jean-Marie Reynaud Twin Mk II
Cables/Interconnects:	Belden 89108 Digital Cable Coax, Luminous Audio Technology Allegro AES/EBU (On Prism DAC). Belden 88281 analog interconnects, via Calrad Teflon phone-to-RCA adapters
Music Used (Genre/Selections):	Camel "Echoes," Arthur Fiedler RCA, Fourplay, Donald Fagan "The Nightfly"
Room Comments/Treatments:	Multiple systems, multiple rooms.
Time Period/Length of Audition:	Three hours for shootout
Other (Power Conditioner etc.):	Brickwall AUD20, Shunyata Hydra, Tripp Lite Line Conditioners, Bybee Signature, Radio Shack 3400mA Power Supply
Type of Audition/Review:	Product Owner