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.


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
Click to view my Virtual System
Shahedk, I was very lucky that dear friend and fellow audiophile had an extra reference clamp and sold it to me for what he had bought it for. The retail price is $600.00, he had obtained it for $300.00, don't know were, and that's what he charged me. By the way, it really makes the transport perform on a higher level compared to the standard clamp.

I never opened up the transport, so I can't help you out regarding the layout or parts that MBL uses in it besides the description on their website.
Hi guys,

I just replaced the stock tubes with cryo'd Mullard CV4004's. Quality of sound is even more pumped up: more 3D, warmer, full bodied voices and instruments, detailed sound. Recommended !

I also have the Accustic Arts Tube DAC now. It reminds me of Lavry sonically. Btw, do you think the Tube DAC is sensitive to a variety of transports?


Hi Chris, I answered your other thread without seeing this one posted by so I have my answer. What transport are you currently using?, have you changed the tubes as of yet? and if so what did you go with and what were your findings?

Great piece and will be hard to replace, to answer your question about transport. The answer would be yes! along with digital cables, not too sure about PC's as I have not got around to those comparisons. I'm currently using a Stealth Dream PC and the IC from AA Dac to pre is a balanced Stealth Indra latest version all with Stealth's connectors. Currently I'm comparing two of the most current Stealth Sextet digital cables, one being AES and the other BNC and the difference is very obvious. Now the problem arises which one do I prefer and why, well that answer is still to come.
I have compared Stealth sextet AES with BNC terminated both are latest version
the BNC ended is belong to my friend and my AES one is between AA Drive II
and AA DacII MKIV, Stealth cables both are very good performer BNC one is more solid,it has more tight bass and more dynamic,AES one has more weighty
and rounded bass and more textural midrange,BNC one has more sparkle on top frequency AES top spectrum more smooth,these are my observations in my system and the differencies are not big but very small margin.
As for the new AA transport I could not find any information about its price here in Europe does anybody know how much its retail price?
BTW one of my friend has an Audio Note transport and claims it is better than AA, has anyone tried Audio Note transport with AA dacs?