Digital Drive: DAC Review: Modded DIO, Scott Nixon Tubed Dac... by jackman

I just got done doing a lengthy listening session between the Smart DIO, an older Modwright DIO, the Scott Nixon tubed DAC, and the stock transformer versus a Bybee PS by Bolder. Several people have stopped by throughout the day to listen in. We listened to a wide range of music including jazz, female vocals in jazz and pop, rock, blues, etc. I'll list my initial impressions of each DAC in no particular order:

Bolder Smart DIO ($600 as tested):
Available at boldercables.com
This DAC was up for sale until recently, however, it is NOT FOR SALE since I acquired a Van Alstine Fetvalve preamp and amp. The FETvalve setup has to be heard. I have listened to these Van Alstine fans on the net rave about his stuff for years and, frankly, dismissed them as kooks. How can something made by some mad scientist-type, older guy from Minnesota sound good? I don't know, but it does...it TOTALLY does. I could not choose a better amp/preamp for the Ellis speakers than the FET valve. The sound is full, large and beautful but this is not a review of the Van Alstine, it's about the DIO. The DIO fits in perfectly with this setup. The overall sound is very detailed without a hint of harshness. Vocals and lead instruments seem to float in the air between the speakers extending far beyond their physical boundaries. Soundstage is also fairly deep with space between instruments. It's the kind of sound I could listen to for hours. When the Bybee PS is replaced with the standard wall-wart, some of the "magic" goes with it. The depth seems to shrink, the soundstage is slightly recessed and the instruments seem to have less weight. I don't know if the Bybee version is worth the additional hundred bucks or so, but the standard PS is definitely worth the hundred and twenty Wayne charges. Very good sounding DAC! Wayne is coming up with a MENSA version of this DAC which is supposed to take the design to the next level. I have not tested this yet but hope to do so in the future. If it's as good as I suspect, I may be shipping my DAC off for minor surgery soon.

Modwright DIO (no longer produced, sold for about $270 + 20 for upgraded wall-wart PS):
This model is no longer in production because Modwright has decided not to mod DIO's anymore, but a friend brought one over to mess around with and I figured "what the heck?". We initially A/B'd it with the Smart DIO using the Stancor PS on the ModDio. The sound was very good. Lots of air between instruments, bass was very strong and the vocals had a smoothness that was similar to the overall sound of the Smart DIO. When we plugged in the Bolder PS, the sound was taken to another level that was very similar to the Smart DIO. Bass was powerful and controlled, highs were even smoother and vocals and lead instruments had a body that sounds very natural. Harmonics were good, and the music sounded like MUSIC. Once we installed the PS, it was very difficult to distinguish this unit from the Smart DIO. One thing I noticed was that the connectors in the back were not quite as nice as the ones Wayne uses on the Smart and the lights near the middle dial were not disabled, however the knobs were not functional (similar to the Smart). The initial price for this unit was bout $150 over the price of the DIO. A real bargain by any standard.

Scott Nixon tubed DAC ($350 delivered):
available at: http://home.triad.rr.com/scottnixon/dac.htm

First of all, this DAC is very small and looks a bit like a toy. My sample was a beta copy, however the actual production version should look a lot like mine. At $350 delivered, this DAC is one of the lowest priced DAC's available. As far as looks...let's just say the money went into the parts and design, not the asthetics. Connectors were good quality, but the standard PS is your garden variety wall-wart. How does it sound? Well, if I was forced to describe this DAC in one word it would be: smooth! It is very refined, and has a sound that reminds me of some of the high $$$ Audionote DAC's I have been testing. It shares the no-oversampling design found on the latest generations of Audionote DAC's. The output was lower than the DIO so I had to adjust the volume level to make it a fair evaluation. Vocals and instruments are not as forward as the DIO but they sound very natural. Soundstage was wide but not quite as wide as the DIO. I could not get a CD to sound bad on this DAC. After several hours of listening, I concluded that I could easily live with this DAC in my main system. If I had not purchased the tubed Van Alstine gear, I would have purchased this DAC immediately. My wife said this little DAC is "cute" and confirmed my "smoothness" comments. If you don't like its looks, it's dimutive size makes it easy to hide. Although it is a tube design, it runs VERY cool and can be tucked away nicely in your audio cabinet. The tube was only slightly warm to the touch after more than 24 hours of continuous play. If you have a system that runs a little on the "bright" side, you should check out this DAC. Don't get me wrong, it is not muffled and does not lack detail, but its overall presentation is slightly laid back and refined. For the money ($350 delivered, fully assembled and, I think, under 300 in kit form) it's almost impossible to beat. I bet a good external PS would take this to an even higher level. I could enjoy music on my system for hours with this DAC. It's a fun yet sophisticated no-frills DAC. Scott is also experimenting with a one piece transport/DAC using some computer CD drives. He has a picture on his site. If these are anything like the Tubedac, they should be an excellent value. He also offers some amp kits and non-tube DAC kits.

Final verdict:In the words of Eve to Adam "this is a hard one...". I was not crazy about the DIO until I picked up the Van Alstine FET-Valve pre and amp, which are very smooth and do not need any more warmth. In my current setup, the DIO works very well. The Nixon TubeDAC is also very nice. If I had a solid state setup (not a warm sounding solid state system)it would be an easy choice, the Nixon TubeDAC. It's a tie between the TubeDAC and the DIO without Wayne's PS. With the Bolder Bybee PS (and my tube based system) I give the DIO the edge. The non-tube DAC from Scott would probably be a better fit for my system than the TubeDAC.

Please note, YMMV. If you have a solid state or ultra-detailed or harsh system, or if you are on a budget, the Nixon DAC may be exactly what you are looking for. If you have tubes, you may want to try the nonTubedDAC from Scott, I think it's the Dackit. If your system is neutral or laid back, the Smart DIO from Bolder is a wonderful performer and tough to beat at this price point.

Thanks,
Jackman