Review: Accustic Arts Reference Tube Hybrid DAC II DA converter


Category: Digital

This will be my third go around reviewing a DAC from the German company Accustic Arts. In between having the MK-3, MK-4, and now their Reference Tube Hybrid as my digital front end, I have had the pleasure to auditioned many of the highest regarded DACS and CDPS in the last couple of years. Many of this digital pieces offered great performance, a few were sonic "turkeys" regardless of some steller reviews, but based on great performance without having to get a second morgage to purchase it, I keep coming back to Accustic Arts.

The MK-4 was a significant improvement over the MK-3 and I still believe it's one of the finer sounding DACS around today. That's way I was skeptical about how much better/different would Accustic Arts new "baby" would be compared with their older DAC.

As in all my reviews I do not get into specifications, you can go to Accustic Arts website to get the details, but always comment on build quality and physical appearance. Like its older siblings the Tube Hybrid is just beautifully built and really is "eye candy". The German engineering and craftmanship is very easy to admire. I know one important technical aspect that this is the first DAC in the world that does not use tubes in the analog section, but somewhere further upstream when bits are still bits before the analog conversion stage. What the tubes are doing and how they are used in the overall design circuitry I don't have the foggist notion, just that sonic bliss is taking place.

When I discovered that Accustic Arts new reference would use tubes I was somewhat concerned for the following reasons: 1) My past experience with tube based DACS, such as the Zanden and a very high level Audio Note, was that they offered a very wonderful midrange but they lacked macrodynamics and extension on both the top and bottom ends. 2) The transparency/clarity and very small details I love in the overall sonic perspective of my system were lost.

SONIC PERFORMANCE

I do not like to result to sonic cliches to describe the sonics of a piece I'm reviewing, but this DAC is a "killer"! I hope all of us can agree that once you get to a high level of excellence in audio gear, their are many great pieces and differences become more quantitive then qualitative. We also have to factor in personnal taste and system synergy in to the equation. Taking all of this into account let me try to explain way this is the best digital I have heard in my system to the present time.

1) The Tube Hybrid retains all of the transparence/clarity and microdetails of the MK-4.

2) I will not say that the Tube Hybrid's extension on the top and bottom are better then the MK-4, but the the overall slam and dynamics is slightly more "lively" and natural sounding. Remember, the MK-4 was no slouch in these sonic areas to begin with.

3) Now we get into the specifics of why the Tube Hybrid is a "killer" in qualitative terms.

A) Unlike adding a "warm/euphonic" aspect to the music this DAC adds what many would call a touch of "bloom/fullness" without destroying the overall linear cohesiveness of the sonic perspective. Another more concrete way of saying it would be that image density and the overall harmonic structure ( leading edge, body, and decay trails) is more natural or what alot of audiophiles would dscribe as "analog" sounding.

B) This DAC offers an overall more sense of liquidity and smoothness, but not at the expensive of slam/punch/dynamics or sounding "soft" to be pleasing to the listener.

C) I have a hunch that another reason why the Tube Hybrid sounds more "real" is that it is more tonally linear compared to the MK-4, and any other digital piece I have heard on Redbook, which makes it sound of one piece top to bottom.

D) The Tube Hybrid offers the most natural timbres I have ever gotten from a digital front end.

E) I don't believe that my system's overall soundstage dramatically improved with the Tube Hybrid, the MK-4 was a champ in this area, but the layering and the air around players also went to a qualitatively higher level.

When I wrote a review here on the GON on the Stealth Metacarbon IC's I struggled to use words to describe the sound of "nothing", meaning these cables just get out of the way of the music so the illusion of real music being played by real people just gets spills into your mind and gut. Well, this DAC hits my sonic ear's the same way, it just sounds more like real music then I have ever heard in my listening room before. The Tube Hybrid sonics can be broken down into specifics, as I have tried to do, but its the overall natural/easy/lifelike sonic illusion without the loss of details,prat,sparkle that makes this a very special piece indeed.

I always end all my reviews with the statement their is no "BEST" in high end audio, but many fine pieces along with the factors of personal taste and system synergy. The new Accustic Arts Tube Hybrid DAC II is among one of the finest DACS on the market today, and while it is not inexpensive it competes with DACS triple its price. This German company sure has some talented thinkers with great ears when it comes to digital gear. If your in the market I highly recommend you audition this DAC before you purchase another.

Associated gear
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teajay
Hi Dev, thanks for the nice words regarding my review. To answer your questions:

1) The DAC does not even become warm to the touch.

2) There is a tube stand-by option, the SS state stays on while the tube goes to sleep, but I just leave it totally on because, which answers your next question, even if left on all the time the type of tubes and how they are used still means you would not have to retube for at least 3 to 4 years. I just ordered a pair of NOS Amperex 12AX7WA that should raise the performance of the DAC another 10 to 20% compared with the stock tubes from China.

3) This DAC has all the virtues of the MK-4, and I know this is a very subjective way of explaining, and then adds a more natural/organic sense to the overall texture of the music. It just sounds more "lifelike" and real. Not, just smooth or euphonic, it still is detailed with great dynamics, but makes it easer to just relax and get into the music.

Thanks Teajay for the answers can't wait to get mine.

Wow! 10 - 20% raise in the performance just changing the tubes, that's huge. You really feel that there is going to be that much especially due to how and where these tubes are located within the dac design? This is going to be really interesting and I look forward to reading your out come, keep us posted.

Has there been much of a sonic change since you have gotten the unit, if so what?

I went onto the "AA" web site and noticed that they have now put up info. regarding this piece, very interesting design.

Thanks again.
Dev, I'm not a "tube dude" at all, however I have now discussed with four tube mavens the differences between great NOS tubes and the best tubes coming from China and they all agree that regardless what the application is you should get a great improvement across the sonic board with changing the tubes. We shall see!

The major change would be it's just opening up more with greater dynamics so far. I have about 250 hours of playing time on it now, and just want to stay home and listen to music.
I want to share that I have had in the AA DAC for about 30 hours a pair of NOS Amperex 1960's "Bugle Boy" tubes, replacing the stock tubes from China, and the results are trully amazing. More transparency, details, liquidity, and a bigger and more airy soundstage, just wonderful results and the tubes are still burning in!

I'll be recieving at the end of next week a matched pair of 60's NOS Telefunken's smooth plates and then will decide what sounds the best in my system.

So Dev, yes the performance of this DAC goes up a great degree with better tubes, and remember I was thrilled with the performance with the stock tubes.

Teajay good to hear that you are enjoying this piece.

How many tubes in total are there in this unit?