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 Teajay, here are two more tubes for consideration that were recommended to me; NOS Telefunken cira 1962 with rib plate and BRIMAR B.V.A. from England.

What is the correct size of Isoclean fuses?, what are your thoughts of HiFi Fuses I'm sure either would be better than the stock fuses. Have you also changed the fuses in your Pass amps?

I am still restraining myself from changing the tubes in the dac for right now even though I can't wait to do so, instead I'm just absorbing the musical upgrade over my MK4 dac which is a wonderful piece.
Dev, here's the information regarding the fuses:

Fuse holder 1A gets a 1A fuse. Fuse holder 102 gets a 1.6A. The arrows on the fuses face toward front faceplate. I have never tried HiFi fuses compared to the Isoclean's, so I don't know how they compare, but I do know that the Isoclean fuses are terrific in their effect sonicly. I will be putting them in my MG-20's, Flora, and XA-100's in the near future.

I have a hunch that the Telefunkens that you mention will have the same sonic signature as the one's I have and the other tube, Brimar, I have no idea regarding their sonics. In the context of my system I love how the Amperex Blue Boys help the DAC just produce beautiful music.

Would you share what your hearing in your own way what the Tube Hybrid offers that is different compared to the MK4? I find it interesting how people use different language to describe what they hear, so it would be great to hear your version regarding the DAC. Finally, when you get your NOS tubes and put them in, I think you will be amazed at how the performance improves, which is pretty terrific with the stock tubes already.
Thanks Teajay for the info. regarding the fuses and I will share my personal thoughts but in the near future as I want to let the unit break-in along with putting in some different tubes.

You really are great at writing reviews and after reading yours I don't really know what to add.

I had a friend over last night who has a very good ear and system and has heard my system many times as I have his, he could not believe the difference and said he thought my system was great before but now is just lost for words.
Hi Dev, was just curious about how its going with your DAC regarding overall satisfaction and if you did put different tubes in and if so what were the sonic results?

A friend was very interested in comparing his new Meitner CDP compared to the AA Tube Hybrid DAC on redbook. Well, lets just say the AA was way better in my system on that day. The Meitner sounded both "dry" and did not throw any were close the soundstage/air around players like the AA.
Hi Teajay, well my unit was really just getting broken-in and I sold my Andra's but I was still really enjoying it. They are being replaced with a new pair of MBL 101E's which I'm awaiting to receive, should get them in about 2-3 weeks time. I did remove the Chinese tubes and put in the Brimar, very silky mid and highs voices to die for and scary real if you go to Andy's tube description describing the sound of these tubes is bang on. The experience was like wiping off a smear on glass that you are trying to see through, everything was just that much more focused. I really am enjoying this unit, one of the nicest pieces I have ever had.

I placed an order for the same tubes you have and waiting for their arrival to compare, thanks for the contact I placed my order with Andy.

I'm sure my system components, amp and pre might be changing down the road since I'm getting the 101's but I'm in no hurry and will be doing comparisons. I read some where you were at a friends and he has the MBL 6010D and you really enjoyed it.