project86
Headphoneus Supremus
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- Feb 21, 2007
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A few years back, I recall hearing praise for a little DAC from Grant Fidelity called the TubeDAC-09. It was a compact unit with a good amount of inputs, offering both tube and solid state outputs. It reminded me of the Maverick Audio TubeMagic D1, also a popular unit in its price range, and I believe the two models were somehow related. Fast forward several years later, and Grant Fidelity has a new model: the TubeDAC-11. Rather than building on the original, the 11 is a completely new design. The only thing it shares with the 09 is the basic form factor and the TubeDAC name.
This time around there should not be any other products showing up with a similar design but different name. The reason? Grant Fidelity contracted exclusively with Yulong Audio to design and build the TubeDAC-11. This product is exclusive to Grant Fidelity; there will not be a Yulong branded version sold overseas in different markets. And as a Yulong design, one can reasonably expect solid performance at a great price. That’s exactly what I anticipated as I waited patiently for my black TubeDAC-11 to arrive. At $350 this would not be the cheapest Yulong design currently available, or the most expensive. I had a suspicion that it would redefine what was possible in its price class. Read on to find out if that ended up being the case.
DESIGN
The TubeDAC-11 is an interesting mix in terms of design. It takes some elements of other Yulong equipment and combines them, while adding some unique aspects all its own. With regards to functionality this is by far the most versatile of all the Yulong gear.
The case is very similar to the Yulong A100 amp – just like the D100 DAC, but with the vented top plate for heat dispersion. The front panel is centered around two large knobs: one for volume control, the other for rotating through the various inputs. A ¼” headphone jack sits between the knobs. LED lights indicate power and digital signal lock. And that’s all there is – simple and effective.
The rear panel is a lot busier. Starting on the right side, we find the IEC power cable receptacle and the voltage switch that allows this device to be used all over the world. Next comes a bank of digital inputs. USB accepts up to 24-bit/96kHz signals, while toslink and coaxial SPDIF handle up to 24/192. Moving further to the left gets us two sets of analog inputs. These allow the TubeDAC to be used as a preamp or stand-alone headphone amp. The area on the far left side is for the three separate outputs. DAC Direct is a line level output which bypasses the pre-amp stage. This is supposedly best for connecting to an external pre or headphone amp. Next is the tube out, followed by the solid-state line out, both of which are controlled by the front panel volume knob. Obviously the one gets passed through the tube section and the other does not.
If you were keeping score, that’s a total of 5 inputs and 4 different outputs if you count the headphone jack (all of which are active simultaneously). That’s a lot of functionality from a relatively low cost device. Plenty of headphone amps advertise pre-amp capabilities, but this is one of the few that I’ve encountered which is actually versatile enough to be used in that role without any compromise.
Internally, the TubeDAC-11 bears resemblance to various Yulong designs. The power supply is a linear design with a relatively large toroidal transformer. The DAC section uses the flagship CS4398 24-bit/192kHz delta-sigma DAC from Cirrus Logic. The integrated headphone amp section is built around twin Analog Devices ADA4075-2 opamps driving a discrete transistor diamond buffer circuit. It is capable of delivering 110 mW into a 300 ohm load, and up to 600 mW into a 32 ohm load.
The USB input uses the ever-popular Tenor TE7022 receiver capable of handling 24/96 signals. SPDIF signals are routed through a Cirrus CS8416 digital audio interface receiver, which tops out at 24/192. Unfortunately the USB connection did not work with my iPad2 via the Camera Connection Kit – it gave the typical error message about drawing too much power. I believe this to be the case with all Tenor TE7022 based USB inputs.
Then we come to something never before seen in a Yulong product: a tube. The included tube is a Chinese 6N11 but can be swapped for 6922, ECC88, 6DJ8, 6H23n, and probably some others that I’m forgetting. The tube acts as a buffer when Tube Out is used, and this device could even be used as a stand alone tube buffer if the owner so desired. Volume control for Tube Out and Line Out adjusts output from zero to 6 Vrms. This allows for even more options, since different external amps will have different expectations for voltage levels on their inputs. With all the options on offer, it’s difficult to think of a scenario where the TubeDAC-11 would not be able to fit into a system. The only things I can come up with is if balanced XLR outputs or 24/192 playback over USB is required. That’s when I remember that this is only a $350 device, and yet still outperforms the vast majority of (more expensive) units in terms of functionality.
Notice similarities between this internal layout and the other Yulong gear.
BUILD QUALITY
The TubeDAC-11 has typical Yulong build quality, which I characterize as fairly high but obviously not “boutique”. It has solid weight to it. Surface gaps are tight and even. The volume and source selection knobs have a nice feel to them. I chose mine in all black to match the system I’m pairing it with, though the silver faceplate version does look very striking. Though I’ve seen it before with the D100/A100 units, the satin black brushed aluminum casing is no less visually appealing.
PACKAGE
Grant Fidelity really pulls out all the stops when outfitting the TubeDAC-11 with accessories. Aside from the unit itself the package includes a power cable, RCA interconnect, USB cable, toslink cable, coaxial digital cable, 1/8th inch to ¼ inch headphone adaptor, and even a hex wrench for opening the case (required for tube rolling). This is one of the most comprehensive packages I’ve ever come across. Granted these are basic cables – they obviously can’t give out their reference quality stuff in a package like this. But it’s still pretty impressive and lets users get started immediately no matter what their system configuration may be.
The only thing “missing” that Grant Fidelity could possibly have included is an RCA to ¼” adapter. The rear Tube Out RCAs can be used to drive headphones directly under some circumstances. It is recommended for use with 300 ohm headphones or higher, though experimentation is always encouraged. I’ve had good and bad results with various lower impedance models which I’ll discuss later. In any case, this adaptor can be had for roughly $5 so it isn’t a significant issue.
EQUIPMENT
This is the associated equipment I used to evaluate the TubeDAC-11
Source: Lexicon RT20 universal disc player, JF Digital HDM-03S digital audio server, Pioneer Elite N-50 network audio player
Amplification: Violectric V200, Analog Design Labs Svetlana 2, Yulong A100, Matrix M-Stage
Headphones: Heir Audio 8.A, HiFiMAN HE400, Lawton Audio LA7000, Sennheiser HD700 prototype, Earproof Atom, AKG K240DF, Audio Technica W1000x
Speakers: Emotiva airmotiv5, Serene Audio Talisman Active
Cabling is by Signal Cable, music played ranging from CDs and 16/44.1 FLAC files all the way up to 24/192 releases. I let the TubeDAC-11 burn in for over a week solid prior to doing any listening.
Pictured with the older siblings: D100 and D18
LISTENING
My initial listening was done using the device as just a DAC via the DAC Direct output. I paired it with some headphone amps which are significantly more expensive, in an attempt to figure out just how much of a bottleneck the TubeDAC would be. The answer to that question? My initial suspicions were confirmed - the TubeDAC did a great job and integrated nicely into a quality setup. It seemed neutral and fairly grain free, with an ease about it that belied its modest price. From reference caliber recordings like Jazz Descargas by The Conga Kings (Chesky 24/96), to quality standard-resolution classics like Asante by McCoy Tyner (Blue Note), to downright poor quality releases such as Jimmy Eat World’s recent album Invented (Interscope), the TubeDAC-11 never felt like much of a weak link. It may not quite have the surgical precision of its sibling the Yulong D100 but the sound is definitely in the same family – which is a very good thing.
Already impressed by that point, I decided to switch inputs to document my experiences with each. With a device like this there is no real easy way to cover every inch of its functionality while keeping the review from becoming a novel. So I’m just going to note my observations of each section:
Solid State output (variable) - This section should theoretically sound very similar to the DAC Direct output. My experience proved this to be the case. With the preamp section in the signal path, there is a very slight reduction in detail. I would almost call it “softness”. But this is very difficult to detect: I had to do A/B switching for a long time in order to flesh out this difference. Even then, it’s not necessarily worse… just slightly different. I wouldn’t be surprised if someone preferred the variable output over the fixed choice. What isn’t subtle is the ability to adjust the output to whatever voltage your amp needs. This enables optimum pairing no matter what amplifier you choose. I’ve discovered that most amps are happy with roughly 2 Volts but some prefer a higher number. It comes down to trial and error, though I don’t usually crank the TubeDAC-11 up past 70% or so (which corresponds to roughly 4 Volts).
Tube output: The implementation here is somewhat different from what you might expect. Where the prior TubeDAC-09 had a tube preamp section paired with solid state output, the TubeDAC-11 is solid state in both sections. The tube portion here is actually used for buffering the output. There is a small collection of dedicated tube buffer devices on the market (some of which are actually sold by Grant Fidelity) that people will occasionally swear by. The TubeDAC-11 has that feature built in. Using the tube output imparts a bit of “sweetness” to the sound. It helps smooth out rough edges, especially in the treble region, and generally makes the presentation more musical. I some cases I perceived a slightly more expansive soundstage presentation, and I found this output to be fatigue-free in all but the most piercingly bright music/amp/headphone chains.
On the other hand, I occasionally felt like bass drum impacts were slightly less distinct through the tube output. A simple test confirmed this: Using the excellent airmotiv5 monitors from Emotiva, I played “Tears in Heaven” from Eric Clapton’s Unplugged. The opening section features some deep, impactful bass drum strikes, which are not supposed to be too prominent in the mix – yet they need to remain noticeable. The relatively compact airmotiv5s are no bass monsters but they dig just deep enough to handle this sound fairly well. With no variables in this setup it was clear from switching back and forth that the solid state output had better leading edges and made that kick drum sound the way I feel it should. The tube output was smoother down there and thus seemed less distinct. This was only detrimental on a few occasions, and I’d say that most of the time the tube output would still be my first choice. Realistically, all three outputs are very good.
I have not had time to swap out the stock Chinese 6N11 tube for something better. I suspect that there are very worthwhile gains to be had even with modest tubes and the price would remain low considering it only takes one. The TubeDAC-11 will accommodate some great sounding reasonably priced tubes such as the Genalex Gold Lion E88CC, the better Electro-Harmonix 6922 variations, and my personal favorite the Russian 6H23n-EB (available in NOS form at under $40). Any of these should go a long way towards improving the already good sound on the tube output. Of course it is possible to go way over the top with expensive tubes but one must keep in mind that this is a $350 device, so spending $400 on an exotic tube might not make the most sense.
Headphone out: the headphone out sounds largely identical to the variable solid state RCA output – it’s clean, crisp, neutral, and fairly transparent. It has a nice quiet background and very respectable soundstage presentation. With no significant coloration, this headphone out is suitable for a very wide range of headphones. From very sensitive custom in ear monitors to relatively difficult to drive planar magnetic full sized models, the TubeDAC-11 is a very capable performer. The only limitation I see is the HiFiMAN HE-6, which has caused grief for quite a few dedicated headphone amps. But the vast majority of headphones out there will match up well. As is usually the case with all in one type machines, there is a gain to be had by adding a stand-alone headphone amp. But I like the fact that the TubeDAC gives a very solid baseline from which most people wouldn’t be tempted to upgrade until they get really serious about headphones. Even then, I don’t feel short changed when listening to a $1k+ headphone with straight from the TubeDAC. Remember that we are dealing with a quality opamp plus discrete buffer design and a nice power supply – much more advanced than a typical chip amp driven by a wallwart that you might find in other do-it-all models from other brands.
Alternative headphone amp: An interesting option is the ability to use the rear panel Tube Out RCA outputs with an RCA to ¼ inch adapter, allowing headphones to be driven straight from the tube buffer. Grant Fidelity lists this as generally being for 300 ohm headphones or above, though as always individual results may vary. I found that the 42 ohm Audio Technica W1000x sounded pretty good – arguably preferable to the dedicated headphone amp. I also really liked the 600 ohm AKG K240DF on the tube out – the bit of extra warmth and smoothness is just what the doctor ordered for extended listening with these borderline overly-analytical cans.
The fact that Grant Fidelity does not include the required adapter in their otherwise exhaustive accessory package tells me that they don’t want people expecting too much from this option. That’s probably not a bad thing – roughly half of the headphones I tried sounded somewhat poor. But the other half sounded pretty interesting, and several of them made excellent matches. So I think it is worth exploring for headphone aficionados. The adapter is roughly $5 so why not?
USB: I’m not usually one to find major differences between coaxial, toslink, and USB inputs. And again I don’t find any major discrepancies with the TubeDAC-11. I think SPDIF has the potential edge when being fed by a very low jitter source. But the USB is more consistent since any decent netbook or desktop computer can get the job done just as good as a more powerful counterpart. The sound here is good enough to notice differences between various software playback choices – a phenomenon I’m still not quite sure I understand. Grant Fidelity does provide ASIO drivers specifically for this device, though I also had success using WASAPI mode. Both options sound equally competent and I wouldn’t hesitate to use this device with USB as the primary source. The one drawback is common with all devices using the Tenor TE7022 receiver – no support for 88.2kHz sample rates.
COMPARISONS
The TubeDAC-11 sits in an interesting position in between true budget models (which I define as being under $200 or so), and “entry level high-end” choices (which I vaguely define as $500-1000). It’s good enough where someone who set out to spend $200 might want to save more and step up to the TubeDAC. It’s also good enough where someone prepared to spend well over $500 may not need to. I do happen to have a few competitors on hand which go for roughly the same price range, and I think the TubeDAC stacks up quite well.
Matrix Cube
The Cube is an excellent compact all in one DAC/amp. It goes for $50 less than the TubeDAC and has a defeatable sample rate convertor option which helps eliminate jitter. In exchange, the TubeDAC gains preamp functionality, hi-res over USB, and of course the tube option. I’ve always enjoyed the warm fun sound presented by the Cube but I don’t think it is quite on the same level as the TubeDAC. In particular, the Grant Fidelity unit makes the Matrix sound a bit slow or syrupy. Resolution is higher and general transparency is superior. The Cube does have the edge in soundstage clarity and depth which I’ve always found to be its strong points. But aside from that the TubeDAC is the superior unit. Note that my Cube is the older model without socketed opamps; the new versions allow opamp swapping and perhaps that would enable the unit to compete better. I still don’t think it will quite be able to keep up though.
Audiotrak Dr. DAC2 DX Muses Edition
I’m still working on the review of this little guy. It’s a very nice unit, a perfect upgrade to those who enjoy the Audinst HUD-mx1 but want to go a step farther. Like the DAC-11, it features a surprisingly complex design, with quality opamps driving a fairly complex array of discrete transistors for the headphone out. It is able to match the TubeDAC in some ways – preamp functionality, hi-res USB, and an overall clean neutral sound. Both are very clear and transparent, with good soundstage presentation and believable timbre. The Audiotrak has slightly more forward mids which makes it a better match for certain headphones (Denon) but worse for others (Audio Technica). It also has more gain on available for driving the HE400 to ridiculously loud levels…. Not that I would ever need to do so. The key difference for me is that the TubeDAC seems able to dig deeper, delivering more impressive low frequency response when called upon. I’m guessing this is attributed to the more robust linear power supply on tap as compared to the wall wart used by the Audiotrak unit. And once again the Grant Fidelity choice has more usability overall. But the Audiotrak does have a few tricks up its sleeve: it can function as a USB to SPDIF converter, it can pass through Dolby Digital files through its optical output, it has dual headphone outs…. And most importantly, it is really really small. That last bit is the reason the Dr. DAC is currently residing in my computer rig feeding a pair of Serene Audio Talisman Active monitors. I’d love to use the TubeDAC there but there simply isn’t room. In terms of pure audio quality, the TubeDAC-11 remains unbeaten in its price category. Obviously I haven't heard every single DAC out there in the sub-$400 range. But a recent audition of the new Cambridge DACMagic 100 ($369) and the Music Hall DAC15.2 ($299) only confirms my high opinion of the TubeDAC-11.
Stacked with D100, D18, and Anedio D2
CONCLUSION
The Grant Fidelity TubeDAC-11 is a stunning example of just how much you can get for your money these days. It has so many functions and not one of them is a weak link – each is well implemented and performs to a very high standard. The nex cheapest product I can think of that offers this much functionality in such a small box (the Matrix Quattro DAC) goes for twice the price. I can absolutely see the TubeDAC acting as the very capable heart of many an audio system.
One must be smart these days – after all, $350 is still a lot of money. If you are strictly looking for a stand-alone headphone amp, or a DAC with USB input only, then the TubeDAC-11 may not be on your radar. Then again, being smart means realizing that your system may expand, and planning for that occurrence. In that respect the TubeDAC-11 has you covered. You just have to get over the idea that more features for the money equates to some compromise. That’s just not my experience with this device.
I commend Yulong for once again delivering a stellar product for a reasonable price, and I commend Grant Fidelity for making the right choice in aligning themselves with Yulong. In my humble opinion there is simply no better buy at $350 than the TubeDAC-11.
