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.

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teajay

Showing 16 responses by dev


Great review Teajay, I'm looking forward to hearing this in my system.

Now that you have had this for a while how warm does the unit get?

Does this unit get left on all the time as the MK-4 does?

What's the tube life?

Regarding your first initial listening experience right out of the box and now what type of sonic differences have you experienced?
Well aren't you having fun, fuses and tube changing. Teajay I finally got my unit and all I can say is WOW! WOW!, your review says it all.

I don't think others really realize just how fantastic this unit is until they actually get one into their own system and they better be ready to pick-up their jaw from the floor.

I am looking forward to changing the tubes and fuses as you have but for now I'm just going to enjoy. I already picked up a match pair but will wait to install.

I exchanged my Supratek Sauv. line stage out of my system and put my ARC REF3 back in prior to putting in the Tube dac and defiantly preferred the REF3. but then I put the Tube dac in, I don't know if it's a synergy thing happening or what but I am just in awe with what I'm hearing.




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.

Teajay good to hear that you are enjoying this piece.

How many tubes in total are there in this unit?
Hi Teajay, have you tried your latest new tubes as of yet and if so what do you find the difference being.

Just curious, was there a reason why you choice these tubes?

Can you forward over where you got them, getting matched pairs from a reliable source is always nice to have and I'll need to get some.

I missed out getting a unit because I was out of town but I'm suppose to get one by week end, no demo's units available.

I bought a pair of PASS X600.5's and I'm really enjoying them with my Andra's, I prefer them over my McIntosh 501's.

I'm going to be able to get a pair of the XA160.5's to demo but I'm going to wait for a bit until I have the new Tube dac in my system for a bit, hope I have made the right choice. The MK4 is a reference piece that I really enjoy in my system.

I also read your review regarding the Flora pre., have you ever had a ARC REF3 or Supratek Sauv. (Cortese line stage)in your system to compare? I'm currently running all cables in balanced so to even demo this unit properly will be a task. Few reason; SE section's are not even broken-in along with I will have to then get a RCA cable and really should be the same as I'm use to which is Stealth Indra(with Stealth connectors, their latest version), as you know not cheap actually more than the Flora and it also needs to be broken-in. Just curious if it really is worth all the effort.
Teajay, Thanks for the info.

Regarding the Pass, I demoed not in my own place but at a dealers 2- X-350.5's with Swan speakers including Esoteric PO-3 combo and Hovland 200 pre. In the same system I heard the XA-100.5's and preferred them. I had the 100's in my system and compared to the X-600.5's and preferred obviously what I have but a fair competitor would be the XA-160.5's in which I will do.

It's looking good, my Dac is at customs so I should have it for the weekend.

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.
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 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.
Mtkhl567 I agree with you the AA Tube Hybrid DAC is a marvelous piece and I suspect there isn't much being posted because anyone who happens to own one is just enjoying their library of music. As Teajay has mentioned changing the two tubes most defiantly improves a already supurb piece. Two areas I have also noticed differences are different transports and via digital connection.

Currently I have two Stealth Sextet digital cables, AES and BNC and there is most defiantly a difference. Using one the images are much more focused but at the same time gives up body and texture. Bass response on one lets you hear the most hidden inner detail notes while the other is more congested clouded over.

Teajay I believe you are using a Stealth Sextet digital cable also, what connection are you using? Have you directly compared using the same manufactures cable but different digital connection? You should because you will be in for a surprise as there most defiantly is a difference in my set-up any ways using the the Oracle as the transport. You mentioned in your post above that a friend had the CEC transport have you had a chance to hear it with your dac? That would be a real interesting piece and I would have interest in your thoughts.

Can you believe it I still have not got around to replacing the two fuses I'm just enjoying the piece so much and keep forgetting to do it, is there that much audio difference?

Hi Teajay your welcome, will be interesting to read your findings once you have tried the Dream speaker cables within your system.

Stealth Digital cables:

1)I will do a more detailed evaluation and post it, I have to say that I was a bit taken back and shocked at the same time when I removed one and installed the other and heard the differences, instantly you could hear the floor noise being substantially lower and everything just seemed to open up. Actually what happened was a couple of friends were over to hear the CAT's and I had one of the digital cables just sitting off to the side and was asked to install it so they could hear if there was a difference or not. You should get the XLR version (AES)digital connection to evaluate your self because there is most defiantly a difference, this could be easily heard in my system with my trans (Oracle) and dac (AA Tube Hybrid) combo.

Transports:

1)Your friend Richard what is his GON name?
2)What differences did you hear from your trans and his CEC, there is a substantial difference in cost.
3)Regarding the new AA trans. do you have any info. pertaining this unit that you care to share? Design differences, cost.

Tubes and fuses:

1)I will get the fuses.
2)The Long Plate tubes, I still have not been able to get a pair any thoughts where I can get some.

Hi Mtkh1567 the Reference AA Transport looks interesting.

I have owned a few of the "AA" pieces and currently own the AA Hybrid Tube Dac which I truly am enjoying. I did own the Line Drive II Transport but found that it was not really offering the improvement that I was exspecting over the previous drive I was using so the search was on and I had the opportunity to demo the latest Oracle 2000 transport and a Kalista Reference transport. The "AA" transport was good but the two others mentioned most defiantly gave me more of what I was looking for, from the first song. I did find the Kalista superior but not by a large enough margin to pay the difference, suggested list price over $50K Wow! The Kalista Ref also did not play a few pieces of music that I had previously never had any issues with, this really disturbed me. A friend brought over his Forsell Transport and it was also really nice but again had issues with not playing pieces and then the seal for the lid just stopped sealing properly. I have heard from others that the Forsell when working properly is hard to beat but very sensitive and there are reliability issues.

I will say with the Oracle 2000 there is a substantial audio difference just swapping the Stealth digital cable from AES to BNC connection. I use Stealth's latest Sextet digital cable with their own connectors and have one in BNC-BNC and the other AES connection.

I own MBL 101E speakers so their Reference Transports 1621A and now the new Ref 1622 along with the one below 1521a spoken of in this thread here does have my interest but the list price of these are how much? The 1521 just alone list for more than $13K I believe which is substantially higher than my current Oracle 2000 so my expectations would be very high and so far just swapping the two different cables and tubes in the AA Dac make substantial sonic differences. The recently new MK2 CEC transport also has my interest but again the list price is double $18K+ and just slightly higher than than the MBL 1521a so again my expectations would be high.

Look forward to reading anyone's thoughts once they try the new AA Reference Transport and comparison against what???

I had made an error within my thread and not sure which one will be posted first but just wanted to make the correction, the MBL 1521a list for $10,950.00 not $13K so I just wanted to make the correction.

The MBL 1621 $24K and the MBL 1622 $27,500K Oracle 2000 is around $8K.

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.
Chris, I have to say I was shocked when I read your comments and disagree with your findings and would look elsewhere within your set-up.

What does your system consist of, my speakers are MBL 101E's which are very revealing and I'm fully enjoying this DAC.