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

Showing 23 responses by mtkhl567

It's been a while since someone posted here. I tried the AA Hybrid Tube DAC this weekend, and I also was mightily impressed with it. I used my Emm as a transport and connected it with a digital Wireworld Gold Eclipse XLR. Had some functional issues, like it doesn't play SACD signals, only RB, and everytime I changed a CD the digital error lght came on and the unit started clicking loudly. Any experience like that? But the sonics were to die for, just like you described in your review. I haven't heard anything digital sound this analog, including the Accuphase P800/D801 combo I listened to yesterday at 3X retail. I know I raved abbout my Emm and thought it much better than any Accuphase, but this tops them all easily in my system. Intreresting reading about the tubes/fuse tuning too. Personally I'd rather have fuses not designed into the signal path, like my Darts, but the overal sound the the AA Tube DAC was very convincing.

Thanks Teajay for the interesting review.
Thanks Teajay, I have no experience with expensive DACs, so I can only say what the AA machine did in my system. Which was pretty wonderful. It just was tonally so right, soundstage wise hugely improved. Listened to some more types of music last night, and just confirmed that it's not only with Jazz and Orchestral music, but also pop and rock, female voice.

I agree with you on the transport of the Emm, it's not a strength... did you know AA are coming out with a new transport this year? What do you think of their current transport?
Wow, I recently heard the Metronome Kalista, and as impressive as it looks, the sound wasn't all that fantastic. The rest of the system didn't help and the room was a hotel room, so not completely fair assessment. However, they were quoting the new price at EUR 36000(!) or USD 57000(!!!) at todays FX rate. If on top of that there is a high defect rate... imagine what kind of damage you can to to your own wallet. Just goes to show that you really have to be careful in this hobby.

I'm going to try out the new AA reference transport/DAC soon, should be impressive.
On the new transport I was told by the only German dealer that carries the whole AA line that the new transport really is only a special Cable Kit installation (from the US) that is easily installed on the current transport afterwards. No definite timing known just as yet.

Any of you have experience with the AA power strips and power cables? I was trying to compare to the PS Audio premier. I know not the same product, but on my amplification the AA strip was better than the premier.

Teajay, just like Moniker, it brought my whole RBCD playback to a higher level across the board. I preferred it much over SACD on my CDSA-SE player. Don't understand why there is so little discussion out there on this wonderful DAC.
I can confirm the new transport (drive 2) will come out at the Munich High-End show end of April. No pricing known yet.

I ordered two Aktiv 6 power strips with some of their power cables. These will probably burn in within a week or so, not sure about the DAC II, most electronic components take 100+ hours of playtime at least. Use a burn-in disc, that would accellerate the process.
Last information about the new AA reference transport Drive 2 is that pricing wise it will be slightly above the DAC II, at least in Europe. This thing better be worth it at about twice the Drive 1 price!!! I'm starting to wonder about the AA value proposition here... as most of the excellent sound comes from D/A conversion IMO
Thank's Hotbird for posting the link to the AA room. Can't really tell, other than it doesn't look like a big ole Oracle transport ... :-)
I have a picture and a technical description of the new AA reference transport Drive II. Send me a mail if you want it. It is indeed a top sliding mechanism, robust as they come. Retail price in Germany is EUR 7,000, that together with the Tube DAC II makes EUR 13,400 plus cables ... pricey combo!
Teajay, here a link to a pic of the open Drive 2. Its in German though.

http://www.areadvd.de/lm/AV_Hardware/messeberichthighend2008.shtml

Regards
Smeyers, my EMMlabs samples upto 5.6Mhz, both CD and SACD, however the same CDs and SACDs I compared sounded better through the AA Tube DAC II, more analog, better imaging, better defined and clearer sound stage, more depth. All I'm saying is that you've got listen to a product and see past the statistics and techno babble. Ofcourse, the same product can sound different in differing systems.
OK, I see what you mean. Yeah, any company's choice to limit their product specifications to best match their own transport, or even in the case of the Accuphase DC801 which only works with their own DP800 transport. Can't blame them for following this strategy. Well, if you're looking for a 32-bit DAC then Esoteric's D-05 is about the same price...
Understand, on the other hand I have a few very, very well recorded 16-bit 44.1Khz RBCDs that puts the majority of recordings, including most SACDs, out there to shame...

I think the sampling question is a relevant one, but it shouldn't be taken out of the context of the whole recording and reproduction chain, its IMHO a smaller part of the overall performance. Maybe in an all digital system its more important though, like what you mentioned above.

At least my CDSA DAC's ability to upsample to 5.6Mhz did not lead to a better musicality vs the AA Tube DAC II on the same music. Maybe I liked the tube coloring ... who knows

Just my 2 cents.
Teajay, what digital interconnect(s) are you using between the Transport and DAC and from the DAC to your pre? Have you experimented at all with this and are you using any isolation under both?
Post OBO hotbird,

Differences between Accustic Arts Ref Drive2 and Drive Mk2

Drive Mk2 : CDM Pro 2 LF – drive module with cast metal frame and involved mechanical decoupling
Ref Drive2: CDM Pro 2 LF – drive module with heavy die cast metal frame and involved mechanical decoupling, embedded in a massive aluminium housing (subchassis-construction principle)

Drive Mk2 : Generously dimensioned magnetically shielded toroidal core transformer (75 VA)
Ref Drive2: Two generously dimensioned & magnetically shielded toroidal core transformer of premium quality (2 x 75VA)

Drive Mk 2: Optimum smoothing thanks to 45,000 µF power supply capacity
Ref Drive2: Very high power supply capacity (61,000 µF) for perfect power supply.

Drive Mk 2: Resonance minimising aluminium housing
Ref Drive2: Extremely stable, massive and resonance optimized housing, primarily made of 10mm aluminium plates, ultra stable and acoustically damped top load cover

Weight
Drive Mk 2: 15kg (35lbs)
Ref Drive2: 18kg (40libs)

Unique to Ref Drive2 only
1) Integrated, specially designed Accustic Arts™ line filter for perfect and extremely clean power supply (line filter switchable)
2) Polarity switch for correct phase of the mains voltage

Unique to Drive Mk2
Drawer with indirect blue lighting for Accustic Arts logo feature (lighting can be switched off)
Thansk TJ for your quick reply. I'm curious to know why you jumped on the MBL transport before seeing if the AA reference transport is something you'd consider. Don't get me wrong the MBL is magnificent stuff, but knowing that the AA reference transport was going to come out... I thought you might have waited to compare before committing yourself...
Shahedk, just be aware that the AA tube DAC II does not handle SACD source material or DVD-A, only redbook CD.
Hi Dev, thanks for sharing your thoughts and experiences. I loved what the AA Hybrid Tube DAC II did in my system and after I've done my room tuning, its next on my list. With regard to their new Reference transport, it lists for EUR 7000 over here and is easily gotten with for a decent price. I'd have to believe that in terms of value and craftsmanship the new AA transport is up there with the DAC when compared to others. I'm a fan of Sergei (stealth) too, and I only use his hyperphone cable now but heard/read very good things about the Indra etc.

I won't get to try out the AA combo until later this summer though... and I am a bit partial about its inability to process DSD signals
Teajay, I'm not so sure that the SE version is going to bring a whole lot of musical improvement to your system in particular. The SE version is only an improvement of the output tubes (Super Premium Military Outputtubes) and the quality control (production) procedures are more elaborate vs the standard DAC II. Knowing that you've tested all output tubes under the sun, maybe all you want to do is find out what exact tubes are that they have in mind. In Europe the SE version will be EUR 400 more than the standard version costing EUR 6390. Acoustic Arts themselves say that not everyone will be able to hear the sonic improvements, the SE version will sound ever so slightly softer with same level of precision. I'm getting my new DAC (different brand) soon, and then I will decide whether to buy the DAC II just for RBCD playback or not.

Btw, anyone heard the AA DAC II against the GTE Trinity DAC? Maybe not a fair comparison...
Ok, here a translation from Dirk Sommer's review in Aprils Image HiFi:

Liked: how much room and dynamism the DAC II solution extracts from standard redbook CD (16bit/44.1khz).
Surprised: how incredibly high value of price to enjoyment ratio you get - even when you have to pay a hefty sum in absolute terms
Missing: the possibility to play at sample rates above 48Khz
To do: compare this dream combo against clearly more expensive components

So obviously he liked the sound of the AA reference combo a lot, but also clearly states its limitations. I loved the sound of the AA DACII as well, and for playback of RBCD its the best I've heard. That doesn't mean much though, as I have not heard a whole lot. My wish would be to be able to have 24/192 or DSD level detail and the wonderful sound of the DACII. Clearly this limitations lies in their unique 32bit DAC implementation. Maybe Steffen Schunk is working on that ...
Hotbird, Mr Sommer compares the Drive II with the Wadia WT3200 (I don't know this piece at all) and says it is slightly better in portraying a realistic soundstage, provides a little more air around instruments. He stresses the difference is not very big though. So pretty much audiophile bla bla speak. He falls short of saying its the best combo he ever heard, but does praise its relative price/value ratio. He says the same about the DAC II vs his PS Audio DLIII. I'm surprised he is not able to articulate more, or better, the differences with his gear.
Just read up on a Wadia WT3200, here's the link:

http://www.lampizator.eu/LAMPIZATOR/REFERENCES/wadia%20WT%203200/WT3200.html

Its basically a Marantz transport (Philips 960) from the early 1990s when CD first came out. I can't believe that Mr Sommers believes the Drive II only slightly better than his ancient transport. Same is probably true for his DAC. My regard for this reviewer has just gone down the drain...
Hotbird - the most recent retail I read was EUR 57100 !!! Outrageous price for sure, reserved for the super rich or super foolish, or both... as its only a small part of a full system.

But again a smaller new player in the business with a radical new design concept being pushed around by the establishment who are trying to protect their market interest with lesser innovative products at diminishing quality levels...

The value for money ratio of the AA DACII is again looking pretty solid!