project86
Headphoneus Supremus
- Joined
- Feb 21, 2007
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[size=small]A few years back I reviewed an interesting little integrated amp called the Lead Audio LA-200. I quite liked it at the time, and looking back I'd say it was somewhat ahead of its time. No ordinary integrated, the LA-200 featured digital inputs and a PWM output scheme, meaning no traditional D/A conversion step was required. Sound familiar? It should, because that sort of thing is popping up more often lately - see NuForce DDA-100, or the M2 and C 390DD units from NAD. When all was said and done I thought the LA-200 was an excellent design and I really looked forward to seeing (and hearing) more from Lead Audio. The designer, Soren Mac Larsen, has extensive history at Danish audio firm Copland, and had some interesting ideas for future products. [/size]
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[size=small] Fast forward a few years, and Lead Audio doesn't seem to have brought much else to the market. They released an LA-120 compact DAC/headphone amp, which had several variations including a battery power option. But the LA-120 was apparently a limited release and I haven't heard any customer feedback on it. Rather than move forward with other Lead Audio branded products, they decided to spin-off the company into a new sub-brand called Northern Fidelity. I don't exactly know what the motivation was behind this move - perhaps they simply concluded "Lead Audio" was not catchy enough, though it's still referenced along side the new name. Northern Fidelity products will be recognized by their unique appearance - see my pictures and you'll instantly know what I mean. The first product is the subject of this review: the NF DAC. Coming soon will be two different versions of the NF AMP - one based on more traditional analog amplification, and one sporting a PWM design, which seems to me like an updated version of the LA-200. Northern Fidelity does not have a USA distributor at time of writing, but hopefully that will soon change. They do have more than 10 distributors throughout Asia and Europe, and can hopefully accommodate requests from the USA should someone be interested in buying. Suggested retail price is $700 but the resellers are free to do whatever they want based on their unique economic situation. [/size]
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[size=small] DESIGN[/size]
[size=small] The first thing that stands out about the device is the curved design. It remains a somewhat understated device overall but the curve gives it some definitely flair and helps it stand out in an increasingly crowded segment. This is a relatively compact DAC and doesn't weigh much at all - an external switching power supply means no transformer inside the case to contribute heft. The wall wart supply was also featured on the LA-200 and though I was initially worried about not having the expected linear power supply, it didn't end up being a problem in that instance... so we'll see if the NF DAC follows that same path. As with the LA-200, there is some fairly extensive on-board voltage regulation, so it's not as if everything rests in the hands of that little wall wart. [/size]
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[size=small] Worth noting: since Northern Fidelity isn't yet officially distributed in the USA, the bundled PSU needed some assistance. While it is universal in terms of voltage, physically the plug did not fit. It required a cheap adapter to create the proper prongs for my area. No big deal, the adapter was just a few dollars anyway - it's simply changing the prong layout, not messing with voltage at all.[/size]
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[size=small] The NF DAC is definitely an "all-in-one" type device. On the input side, it has coaxial and optical SPDIF as well as asynchronous USB. Coax and USB are both capable of 24-bit/192kHz, while Toslink has a maximum sample rate of 96kHz (as is common for that type of interface). Outputs include separate RCA jacks for fixed and variable output, XLR outputs (fixed only), and of course the headphone output. The front panel is simple and efficient - one button toggles between the three inputs, another button toggles the four outputs, and each has its own LED indicator. Only one output (the selected one, obviously) is active at any given time. A volume knob applies only to the variable RCA and the headphone output.[/size]
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[size=small] Internally, the device uses a good selection of hardware: XMOS USB implementation, TI PCM1796 DAC chip, TI SRC4392 asynchronous sample rate converter, very high quality clock paired with a dual-stage buffer, and LM49723 opamps - 4 of them for for I/V conversion and buffering of the output stage, and 2 more for the headphone section. Volume control appears to be handled in the digital domain, probably through the PCM1796 itself which does offer that function. All outputs get their own relays and switching between them results in a mild audible clicking noise, but no unwanted pops through the actual outputs - which is of course the whole point of the relays. [/size]
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[size=small] Overall layout:[/size]
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Master clock with dual-stage buffer:
XMOS USB:
PCM1796 DAC:
Dual LM49723 opamps for the headphone stage:
Output stage using quad LM49723 opamps and relays:
SRC4392 combo chip handling ASRC plus DIR duties:
Outputs:
Front panel is nice and thick:
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[size=small] Remember the puny wall-wart power supply? Don't feel too bad about it. The NF DAC uses some tricks like regulators from On Semi augmented by low dropout regulators from National Semiconductor as well as strategic capacitors throughout the circuit. As with the LA-200, the thought process here is more about precise power where it's needed instead of a massively overbuilt supply. I normally prefer the satisfying heft of a big PSU, but I can't really argue with the results achieved here.[/size]
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[size=small] The PCM1796 is what I'd call a second-tier chip - and I mean that with no disrespect whatsoever. With an SNR of 123dB, it's just behind TI's 127dB flagship PCM1792 and its variants. That places it above many of their newer models such as the PCM5122 (112dB). The PCM1796, a 24-bit chip, was later repackaged as a 32-bit model and renamed the PCM1795. Don't be fooled - take a look at the datasheets and you'll find both models are identical, with the 1795 merely adding a 32-bit input capability but not improving anything else. The PCM1796 is a well proven chip, used by the likes of Accuphase, YBA Design, Vincent, Creek, and Bel Canto, just to name a few. Designer Soren Mac Larsen says he tried some of the well-regarded Wolfson chips and they sounded pretty good, but not as good as the TI chip in this particular implementation. The NFD DAC carries over some elements of the earlier Lead Audio products, so its analog circuitry is built around the PCM1796 which is a current output DAC. The Wolfson models are Voltage output so would require more tweaking of the established Lead Audio design to achieve max performance. In the end his choice makes sense to me. [/size]
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[size=small] The SRC4392 chip, which in this case also functions as a digital audio interface receiver, upsamples incoming signals to double their native rate. So your standard Redbook 44.1kHz tracks get bumped up to 88.2kHz, which has been theorized by some designers (Dan Lavry chief among them) to be a near ideal sample rate for most DAC chips to handle. The SRC4392 has been paired with the PCM1796 (and its cousin the PCM1792 which is pin compatible) many times with satisfying results - Musical Fidelity does it frequently, with their M6CD, M1 DAC, and A1 CD Pro being three examples. Bel Canto and Primare are some other brands to use the same setup though I don't recall their model numbers off the top of my head. My point here - this is a well proven design that's been at the heart of many high quality CD players and DACs costing a lot more than the Northern Fidelity DAC. [/size]
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[size=small] Noteworthy specs on the device: THD+N (at 1kHz): less than 0.001%. SNR is 120dB (A weighted). Total jitter is less than 100 picoseconds, though we aren't told if that is RMS or what. Line out has a max voltage of 2.7V which is somewhat higher than the usual 2Vrms. The headphone amp can swing 3.6Vrms into a 600 ohm load, and has an output impedance of 25 ohms which is somewhat high for certain headphones and perfectly acceptable for others. Other odds and ends include the SMSC USB3318 USB transceiver, an STM32 ARM core microcontroller, a CMOS from Macronix, and an EEPROM from Atmel. Clearly this is no simple design with a few opamps and a DAC haphazardly thrown together. [/size]
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[size=small] EQUIPMENT[/size]
[size=small] I listened to the NF DAC with the following equipment:[/size]
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[size=small] Transports: Auraliti PK90 with NuForce LPS-1 and Audiophilleo 1 with PurePower, MacBook Air with Audirvana, Dell 17R with JRiver, Marantz DV8400[/size]
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[size=small] Amps: AURALiC Taurus, Violectric V200, Icon Audio HP8 mkII, Yulong A100, NuForce HAP-100, Firestone Audio Bobby, Stax SRA-12S[/size]
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[size=small] Headphones: Sennheiser HD800, Beyerdynamic T1, Audeze LCD-2, HiFiMAN HE-400 and HE-500, Heir 8.A, Westone ES5, Frogbeats C4, Aurisonics AS-1b, Cosmic Ears BA4, Stax SR-007mkII[/size]
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[size=small] Power: APC S15[/size]
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[size=small] The system is wired via Cabledyne Reference Silver AC, XLR, RCA, and digital cables. It sits on a Salamander Archetype 5.0 rack. I burned in the NF DAC for quite a long time, well over 100 hours, before any critical listening.[/size]
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[size=small] Good match for the Violectric V200 amp:[/size]
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Sennheiser HD800 with Toxic Cables Scorpion (balanced, but with matching adapter):
Paired with Analog Design Labs Svetlana 2 SET amp, driving LCD-2 with Effect Audio
Thor cable:
Very similar in size to the Firestone Audio Tobby:
Auralic Taurus - this is actually the new MKII version, I mostly used the original for
this evaluation:
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[size=small] SOUND[/size]
[size=small] First off, before I start on the Northern Fidelity DAC, I have to comment on how competitive this segment has become. It used to be the case that sub-$1K DAC market was just not all that impressive. You generally wanted to move up higher to find anything really exciting - I remember steering more than one person towards the Musical Fidelity X-DAC v3 ($999) back in 2004 or so. Going much lower than that involved reducing options and severely limiting quality. Fast forward to 2013 - I'd say the minimum cost for a great sounding DAC has dropped significantly. Not only do excellent sounding DACs exist under $1K; there are tons of 'em! You've got some reasonably good ones that don't cost a lot such as the Audioquest Dragonfly, and some step-up models with better sound and/or more features like the Schiit BiFrost and the HRT Music Streamer stuff. And there are some which I consider excellent - the Yulong D100 mkII, Parasound ZDAC, and Resonessence Labs Concero among others. The field is bristling with great choices and at this point it would require something absolutely special to make a dent in this crowd. Keep that in mind as you read on.[/size]
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[size=small] With that disclaimer established, the NF DAC is a very good sounding device. The presentation is mostly neutral, with a slight inclination towards warmth and fun. It's sufficiently detailed but not at all overly-detailed. It hits hard and deep with surprisingly nice texture in the bass that belies its wall-wart power supply. I also particularly like the way it does air on the top end - present and believable but not in your face or "look at me I'm sooo high fidelity!" Mids come across as slightly rich compared to some of the more flat peers on the market, which of course can be good or bad thing depending on your preferences. As I said, the word "fun" seems to apply well here, with the NF DAC doing a small contribution towards making everything sound a bit better than it has the right to sound. It's certainly not an overly warm, mushy, romantic sounding DAC, but it does tip the scales just a tad in favor of what I'll call "boogie factor". I already hate myself for using that term but I think it sums up what I mean better than anything else.[/size]
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[size=small] From Mozart to Michael Jackson, Nightfall to Nancy Bryan, what the NF DAC excels at is involvement. It has just the right balance to keep me engaged, but still be aware of the micro details and nuances. This is noticeable whether using XLR output to a Violectric V200 or RCA output to the Icon Audio HP8mkII. I'd say both outputs sound just about identical, which I suppose is a good thing. I also don't notice any difference between the fixed RCA out and the variable option with volume cranked to full scale. Which makes sense as the volume is done in the digital domain, so there's nothing extra in the signal path that would degrade the sound. [/size]
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[size=small] Speaking of sounding the same - the digital inputs all perform roughly on the same level. The XMOS based USB option does better than a basic DVD player used as transport, but as I try an older Marantz DV8400 (which was reasonably expensive when new, but that was a decade ago) I find SPDIF is just about indistinguishable from USB. And that includes optical as well as coax. I'm thinking this comes from the upsampling process. Some designs (Benchmark DAC 2 for example) have their asynchronous USB input bypass the ASRC process and go straight to the DAC, while all "legacy" inputs get the upsampling treatment. I don't know if that's also the case here but however they are doing it, Lead Audio largely makes transport quality irrelevant. And I didn't notice a difference between the ultra-clean SOtM USB output of my Auraliti server and a more basic USB connection from my MacBook Air running Audirvana. I guess that fits accordingly with the overall them of this device - it's easy to get enjoyable sound out of it. Use any input, any output, (almost) any source, and you'll get satisfying results.[/size]
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[size=small] For amplifier matching, I enjoyed the NF DAC with most everything I tried, but a few really stood out. The AURALiC Taurus is one of the most resolving amps out there, and gets somewhat picky with sources - it really needs something high quality, or else it just shows the flaws. It sounded really great with the NF DAC, which is among the cheapest DACs that I would choose to pair with the Taurus. It might be the slightly forgiving nature of the NF DAC, but it fared better than some of my more expensive DACs could in this particular combination. I liked how well it did deep bass - again, surprising for the lack of a big linear power supply. I also really liked the NF DAC with the Firestone Audio Bobby amp. Normally I pair Bobby with the matching Tobby DAC ($1100) which is more on the analytical side, and they make a great team. But with the NF DAC, Bobby takes on a different personality, becoming more laid back and relaxed. There's less detail, and transients are not as fast (a strength of the Tobby DAC), but in exchange you get a more flowing presentation that works especially well with potentially bright cans like HD800 or T1. And thanks to the balanced connection, the NF DAC makes the most of the fully balanced Bobby amp, where many other DACs in this price range couldn't do that. I guess the biggest compliment I can give the NF DAC - I'm comfortable using it in a system with amplification and headphones costing far more than the DAC itself. It doesn't even feel out of place in my Stax rig which normally gets a DAC costing 5 times as much.[/size]
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[size=small] Then we come to the headphone amp, which is something of a mixed bag for me. It's not terrible, not completely objectionable by any means, but I can't shake the feeling of a slight "thinness" dominating the sound signature, no matter what headphones I use. Overall frequency response seems good with no crazy dips or peaks, but I don't feel a lot of grunt in the lower registers. Part of it may be tied to the higher output impedance which means low impedance headphones and IEMs will have a poor damping factor, and multi-armature IEM designs suffer from altered frequency response due to their wild impedance swings. I also hear a mildly intrusive hiss in the left channel which doesn't show up with full sized headphones but is pretty annoying with IEMs. [/size]
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[size=small] So IEMs are out, but what about full sized headphones? Audio Technicas are out due to (most of them) already sounding somewhat thin already. Grados are out due to the output impedance mismatch. Same with Ultrasones. What's left? Sennheiser HD600 and 650 which actually sound pretty good here, HD650 in particular due to the increased bass it has over the HD600. Higher impedance models from beyerdynamic seem like they would work well too. I'd probably go DT990 in the 250 ohm variety for best results. And then the planar models: since they don't care much about the 25 ohm output impedance, and are both on the warm/darker side, my HE-400 and LCD-2 are fairly good from the NF DAC. With both models, there's a slightly reduced sense of bass impact compared to my other amps, but it still sounds pretty good overall. My Thunderpants planars also do pretty well - clear and involving, with just a hint of lightness.[/size]
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[size=small] The thing about the NF DAC - it's an all in one device. You pay a little more with the assumption you'll be getting extra features that will come in handy. And with an HE-400 or an HD650, that's exactly how it plays out. With some other headphones? Not so much. As I mentioned, this segment is incredibly competitive, and the NF DAC needs to really perform well to stand out. While I think it does reach a notch or two higher than the $400 Asus STU with regards to DAC sound quality and overall features, it doesn't do much better than the Asus as a headphone amp. And that might be a deal breaker for some. The amp section is definitely not on the level of something like a $500 Yulong D100 mkII with its more advanced output stage. So while it's great to have an all in one, space saving unit, the amp is somewhat uninspiring with a large number of headphones. [/size]
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[size=small] On the other hand, as a relatively compact and full featured device, the NF DAC perfect for desktop use. I connected it to a pair of Adam Audio F5 active monitors, using USB from a MacBook Air running Audirvana, and it did an exceptional job. I really like the method of switching between active outputs - I leave the line out active most of the time but switch to headphone mode for late night action. Some units like this keep the line out active all the time which means I'd have to manually power down the monitors. And in terms of sound, I paired the fixed output with a Nuforce HAP-100 preamp, and it sounded indistinguishable from the variable output. Which means the NF DAC is basically transparent in that regard. Nice.[/size]
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[size=small] COMPETITION[/size]
[size=small] As I mentioned, competition is fierce in this price range. The Yulong D100 MKII has been my go-to recommendation at around $500. It certainly looks like a more serious audiophile component, with the linear power supply and the discrete buffer stage on the headphone output. I think the NF DAC surprisingly beats it as a DAC alone. Not by a huge margin, and they both have their own character, but more often than not I'd choose the NF DAC. Which is impressive in and of itself. But for direct headphone monitoring the D100 has a better integrated amp that works with a wider variety of headphones.[/size]
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[size=small] The Parasound ZDAC ($475) is very close to the NF DAC in sound signature. Parasound comes off as just a little darker which makes for less implied detail and sometimes equates to a more fun, bouncy presentation. Even if we adjust for sound signatures, the NF DAC just seems like a slightly higher resolution device. Both have headphone stages which are fairly selective about what they are happy pairing with. I end up preferring the NF DAC by a small margin, while maintaining a very high level of respect for the Parasound. [/size]
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[size=small] I definitely like the NF DAC more than the PS Audio NuWave ($999). It seems far more balanced and easy to listen to. Remember when I said the NF doesn't scream for attention? The NuWave is a perfect example of a DAC that does. And it comes across as very obvious, becoming fatiguing in a short period of time. The NuWave is beautifully built and looks like it should be killer, but somehow just misses the mark in my opinion. The NF DAC, while unique with the curved enclosure, does not look like it would be in the same league, but ends up sounding far better - more balanced, more engaging, and ultimately more tonally correct.[/size]
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[size=small] CONCLUSION[/size]
[size=small] I'm still not positive why Lead Audio had to start a new line, but I have to say I like the name Northern Fidelity, and I love the appearance of the curved enclosure. With matching amplifiers on the way, one could assemble a very attractive desktop system using stacked NF DAC and NF AMP. But aside from looks, does the NF DAC compete in this tough segment?[/size]
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[size=small] In the end I'd say yes. It's not a slam dunk victory, but the NF DAC does raise the bar above my favorite $500 units. It doesn't compete on the same level as the best $1000+ devices, but neither does it give up a huge amount of performance. So I'd say the MSRP of $700 is appropriate, and I appreciate having a "middle ground" option in that range. With so many intriguing choices out there above and below that price, any major flaw here would be a deal breaker. The headphone output may be just that for some users, but overall the NF DAC is still worthy and deserves some attention. If you like a detailed but slightly smooth presentation that makes everything sound great, and need a good multi-purpose solution, the Northern Fidelity NF DAC definitely has potential. [/size]
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