At the 2014 CanJam @ RMAF, an audio industry friend and I were chatting about gear we've been enjoying, and I mentioned theChord Hugo. "Have you checked out Aurender's Hugo competitor?" he asked? When I answered I hadn't, he insisted I should. As chance would have it, I later ran into ComputerAudiophile.com founder Chris Connaker, and he also asked if I'd heard the new Aurender portable DAC/amp. That was two people I knew and respected asking me about the same product, so I asked Chris if he could introduce me to Aurender. Ten minutes later, I was meeting with Harry Lee and other Aurender team members, listening to the Aurender Flow for the very first time.
Okay, to be clear, the Aurender Flow was already in development before the Hugo was even announced, so it wasn't created in response to Chord's mega-successful portable DAC/amp combo. Once you put them both on a table, though, there's no avoiding the comparison. The Aurender Flow is a high-end, high-res portable DAC/amp combo; it is clad in a robust silver aluminum chassis, and it's more or less similar in size to the Hugo.
In terms of styling, though, they are certainlyverydifferent. The Flow is sharp corners and smooth flowing lines, with a beautiful (and huge) volume knob dominating its topside, and a digital display smack dab in the middle of that volume knob (which I'll get to shortly). The Hugo sounds absolutely amazing, but it is a strange creature to behold, with its domedhey-check-out-my-FPGAviewing window to the PCB, unusual recessed volume control ball thingie (that glows different colors to indicate volume levels), recessed jacks galore, a host of LED's of varying colors that a colorblind guy like me has a hard time making heads or tails of, and strange little chassis design flourishes that seem almost random. The Flow looks decidedly more straightforward and business-like in comparison.
In terms of specs, the comparisons certainly have more in common than their chassis styling. Both are 32/384-capable via USB. Both are 24/192-capable via optical. Both will play DSD files up to DSD128. (The Hugo also has a coaxial digital input, which the Flow does not.) Rated output power comparisons show the Hugo a bit more powerful into 32 ohms (600mW for the Hugo versus 570mW for the Flow); and the Flow is a bit more powerful into 300 ohms (87mW for the Flow versus 70mW for the Hugo). Both have vanishingly low output impedance specs, with the Hugo at 0.075Ω and the Flow at 0.06Ω. Battery life for the Hugo is rated at around 12 hours (which might be a bit optimistic) and the Flow at 7+ hours (which is probably mildly conservative). The Hugo's DAC is based on a custom-coded FPGA DAC, and the Flow's DAC section uses the Sabre ES9018K2M.
Due to the display in the middle of its wide volume knob, and the media control buttons on the side, the Flow is regularly mistaken for a standalone media player, which it isnot. The display shows a visual volume indicator, various functional modes, battery status, current sample rate, and other bits and bobs. The buttons are for playback control (of your computer), and can control iTunes and some other media player software (play, pause, track backward, track forward).
Another reason people seem to assume the Aurender Flow is a portable media player is because it has an mSATA slot into which can be installed an SSD drive up to 1TB. Again, to be clear, the Aurender Flow is not a portable media player like an Astell&Kern players. It is a DAC/amp combo, and installing an SSD drive turns it into a USB 3.0 media storage device. I've installed aSamsung 1TB SSDin mine, and the read/write times are fast. If you're still unclear why one would want an SSD drive in his DAC/amp, here's my personal answer: My laptops of choice is a MacBook Air that has only two USB slots. With the Aurender Flow, both my media storage and DAC/amp functionality are served with a single USB slot. It's less to carry, and it keeps my other USB slot free for other things (like my photo storage drive or other peripherals).
As for how its performance compares to the Chord Hugo, I'd say the Aurender Flow is so far the strongest competitor to the Chord Hugo I've listened to. If your primary headphone is a sensitive IEM, you might actually prefer the Aurender Flow, as, in terms of self-noise with an ultra-sensitive in-ear, it isdeadquiet, whereas my most sensitive IEMs can touch and reveal the Hugo's noise floor. When it comes to sensitive IEMs, I also like how the Aurender Flow always jumps back to -90dB volume level (-110dB is its lowest setting) when you unplug the headphone from it, which is nice for added hearing safety.
The Aurender Flow is a very resolving DAC, to my ears approaching (but not quite reaching) the Hugo in terms of inner detail and accurately conveying imaging and soundstaging (using albums I was present for the recordings of as my references). With most of my over-ear headphones, and with my loudspeaker setups, I still have to give the edge to the Hugo, though, for its ability to present a sense of solidity--a corporeality--that I typically associate with good tube gear. The Flow is good in this regard, but that edge is the Hugo's. This is not faint praise--the Hugo is far more expensive, and is one of my favorite DACs ever, regardless of form factor. With two portable products like these at the top of their games, there'll be some who prefer one over the other, and I think the Aurender Flow will win the battle with some of you.
This has been a very heavy travel year for me, and the Aurender Flow has edged out the Hugo as my carryon-only travel companion, due to its ability to be both my DAC/amp and my media drive all-in-one. When I travel extra-light, my best in-ears always win the role of primary headphones, and the Flow's advantage with my most sensitive in-ears also contributes to its status as my current #1 travel DAC/amp combo.
If you don't need the SSD drive, the Aurender Flow comes in at just over half the price of the Chord Hugo. Even with a 1TB drive, it's priced at just under $1800, which is still $700 less than Chord's portable marvel.
Though they're best known for manufacturing and selling products based on the O2 and ODAC designs by the enigmatic nwavguy, JDS Labs also manufactures products they've designed entirely in-house, now with their C5 portable headphone amp, and their C5D portable headphone amp and USB DAC combo.
From the outset, JDS Labs made clear that the C5 and C5D weren't intended as a response to the O2 and O2/ODAC, but, rather, as complimentary to the line. The C5 and C5D are for users who need a smaller amp with USB recharging, and who could benefit the most from super-fine volume control for sensitive headphones and IEMs. To achieve perfect channel matching with super-sensitive headphones, JDS Labs opted for a 64-step digital volume control.
The C5 amp section also features two gain levels (selectable by pushing the volume control in to toggle), and a three-position bass boost (off, medium, high). One thing that those DIY'ers among you might find useful is that the C5 runs on JDS Labs' fully open source Arduino firmware, so (if you use Arduino) you can change the behavior of the C5's volume control.
The C5D adds a low-jitter PCM5102A-based USB DAC that supports PCM up to 24/96, including 24/88--I only mention that last part, because the ODAC does not support 24/88. Whereas nwavguy thinks re-sampling my 24/88 files to 24/44 is trivial, it's just one more thing I'd rather not have to even think about--I just want to play them without the extra steps, so I like that the C5Ddoessupport 24/88. The USB implementation is async, and the C5D's DAC section also uses the Analog Devices ADuM3160 for galvanic isolation. By adding the DAC section, battery life on the C5D is (not surprsingly) shorter than the C5 (6 to 8 for the C5D versus 11-14 hours for the C5). I personally went with the C5D.
With my most sensitive in-ears, self-noise is nonexistent--that is, the C5D is dead silent, to my ears, and that's a big plus. For the most part, I do like the volume control on my C5D, and the channel matching sounds perfect down to the C5D's lowest volume setting--however, the very first step on the C5D's volume control is louder than I'd like it to be with my most sensitive IEMs. Is it a deal-killer? Far from it--it's still quiet, just not as quiet as I'd like that first step to be; and with headphones thataren'tsuper-sensitive IEMs, it's perfectly fine. Is this a behavior I can remedy to my complete satisfaction by getting into the firmware with Arduino? I'm not sure, but I'll ask, and maybe one day try it, if the answer is yes.
In a word, I'd describe the C5D's sound signature asclean. If you favor warmth or bloom, look elsewhere, but with my Sennheiser MOMENTUMs, OPPO PM-1, and AKG K7XX (just to name a few examples of headphones that pair very well with the C5D), I really dig the C5D. The variable bass boost is also nice for a dose of energy down low for anemic, overly-lean recordings.
If you've been hoping for a more portable-friendly O2/ODAC, the C5D seems to me to be created to be in keeping with nwavguy's spirit--even though it's an entirely unique and independent design--and I can't think of a company better suited to successfully do that than JDS Labs.
iFi Audio micro iDSD
Written by Jude Mansilla
Over the last few years, iFi has been getting a lot of attention from the Head-Fi community, but perhaps never more than now, as the community helped iFi crowd-design one of their latest products. The resulting product--the iFi Micro iDSD--has been met with a lot of enthusiasm on the forums, and, in my opinion, it's well deserved.
I really like how iFi was able to capture most (maybe all?) of what the crowd-designing crowd wanted most, and with only one SKU. That is, instead of having to pick and choose different configurations or model numbers to get a specific feature set, there's only one iFi Micro iDSD model, and you customize it on-the-fly by flipping the appropriate switches. You prefer fixed RCA output to variable output? There's a switch for that. Sensitive in-ear? Flip a switch, and you get a dead silent background and great volume control range for your IEM. Brutal-to-drive HiFiMAN HE-6? Flip a switch and it's a 4-watt max output beast of an amp. Want to mess with different digital filter settings? Polarity? A little bass boost? 3D HolographicSound processing for headphone or speakers? Yep. Switches. For all of it.
As far as connectivity goes, the Micro iDSD has async USB 2.0 input, S/PDIF input/output via a combo coax RCA/optical jack, 3.5mm analog input, RCA stereo outputs, and, of course, a headphone output (6.3mm, better known as 1/4"). iOS device users will likely appreciate that its USB jack is designed to directly accommodate the Apple Camera Connection Kit without needing any adapters or additional cables--this is a huge plus for those whose portable rigs are fronted by an iPod Touch, iPhone or iPad. The Micro iDSD even has a 5V/1.5A USB type "A" port that draws on the Micro iDSD's big 4800mAh lithium-polymer battery to charge your USB devices.
Able to play DSD up to DSD512, DXD, and PCM up to 32-bit/768kHz, the iFi Micro iDSD is, for all practical purposes, a future-proof DAC, covering every existing digital music format I know of, as well as file types I don't even think we'll see in the foreseeable future. Fortunately, the iFi Micro iDSD is not only versatile, it is also anoutstandingperformer, with an excellent, neutral presentation that avoids being harsh or unnaturally edgy. As a DAC, the Micro iDSD is very revealing, with an ability to reach the inner detail of great recordings that I simply wouldn't expect for $500, and putting it at the top of my portable DAC recommendations at anywhere near this price.
As a portable amp, the Micro iDSD's flexibility is completely without peer, in my experience. With even my most sensitive in-ear monitors, the Micro iDSD's background is, to my ears, free of any self-noise--dead quiet. With the iEMatch switch in its "Ultra Sensitivity IEMs" position (and power set to "Eco"), the ability to turn the volume knob through a nice range--without the hair-trigger volume jumps that can occur with super-sensitive IEMs with most amps--is absolutely refreshing. Again, the Micro iDSD's controls allow its ample power to be controlled to feed anything from those super-sensitive IEMs to the power-devouring HiFiMAN HE-6, and anything in between.
While I haven't been using the bass boost or the 3D HolographicSound processing much, I do appreciate knowing they're there when I feel the need, and these features only add to the Micro iDSD's versatility.
Fortunately, the Micro iDSD leaves me with only a couple of minor gripes. First, for a portable, it is rather large, similar in size to theCEntrance HiFi-M8(and a bit larger than theChord Electronics Hugo). Also, for something so adept at driving ultra-sensitive IEMs, I wish the Micro iDSD had a 3.5mm headphone output in addition to it's 1/4" one. Personally, I would be willing to sacrifice the 3.5mm analog input on the front to have a 3.5mmoutputin its place.
Perhaps everything I've written describes a complex product, which is because the iFi Micro iDSD is indeed a very complex, sophisticated product. It is, however, exceedingly easy to use, so don't be intimidated by its feature set. Regardless of what price range you're shopping in, if you are looking for a portable solution that can also stand in as your primary headphone system, the iFi Micro iDSDhasto be put on your list of candidates.
"If you ever need a portable USB DAC + amp that can just about do it all, do it well, and do it without costing a limb, I reckon this is it."
Going into CES 2014, I had never heard of the Chord Hugo, and I had no specific plans--in a very packed CES schedule--to stop by the Chord Electronics exhibit. However, David Chesky (of Chesky Records and HDtracks.com) texted me to ask me to check out something called the Chord Hugo, and to let him know if I thought it was worth getting. (David was stuck at his own HDtracks.com CES exhibit, where people who stopped by would certainly want to see and meet him.) Time had passed, and I still hadn't seen or heard the Hugo (and still didn't know what it was). Another message from David popped up, again asking me to check it out for him. So I finally went--still having no idea what this Hugo thing actually was--and was greeted by Chord Electronics' founder John Franks, who had been waiting for someone from Head-Fi to stop by.
I'd seen Mr. Franks at audio shows before, and he always seemed to me like a man normally possessing of confidence and brio. That day at CES, though, he was positively brimming with it. He walked me over to a little component that looked rather like Chord's machined aluminum full-size components, only this one in miniature--including their signature circular glass porthole through which some of its circuity was visible (a detail Chord is well known for).
I should say at this point that Chord Electronics has long been known for its expertise in digital component design, and their gear is typically designed for--and priced for--the higher end of the audio market. So when John Franks said that not only was the $2500 Hugo a portable DAC/amp combo, but it was also their current flagship DAC, and the most advanced DAC they'd yet designed, and just happened to be portable--there was that brio, in full effect. I also saw that they had a Sennheiser HD 800 plugged into it; and seeing that, my first thought was that these guys might be way too plucky for their own good--when the marvelous HD 800 is used to demo a portable amp (or portable DAC/amp), the results are, more often than not, less than ideal, the HD 800 being a remarkably picky German genius. Then I listened to this HD 800-driving setup, and understood right away why Mr. Franks looked like the Cheshire Cat the moment I introduced myself. It sounded awesome.
In the 13 years since Head-Fi's founding, few products I can recall have taken the audio world by storm the way Chord Electronics' Hugo has this year. As someone who now himself has a Hugo, I can say the hype is understandable, and in every way deserved, because when it comes to its sonic performance, to my ears, the Hugo just doesn't set a foot wrong.
However, before I get to its sound, let me first get out of the way those things about the Hugo that I find a bit silly, almost all to do with its somewhat wacky layout and physical design. First of all, nothing--and I mean nothing--on the Hugo is labeled. Just memorize which button does what--oh, and memorize the nine sample rate colors, the three crossfeed indicator colors, the five input source colors, and the four battery life colors. Even the volume control glows in six different colors to indicate volume level.
Also, all of the Hugo's audio jacks, except one (the 1/4" headphone jack), are recessed, limiting cable and plug choices. The volume control and all those colored LED indicators are on the Hugo's top surface. This means that if you want to pair it with a digital audio player (virtually all of which have front-facing screens), then the Hugo has to be placed underneath, upside down, so you can use the Hugo's volume knob and see all the pretty indicator lights. This also means that when you set your portable stack down, you have to set the Hugo down face-first and lift it up every time you want to change volume or see what its seemingly endless variety of LED colors are indicating.
However, once you've figured out the Hugo enough to get some music out of it, its sound will make you forget all of the aforementioned quirks and silliness. The Hugo’s sound places it--to my ears, beyond any doubt--in the top tier of DACs I've had here, ever, period. That it's portable (on the larger side of portable, but still portable), and that it's priced at less than $2500…well, let me just say that the Chord Electronics Hugo is to DACs what the KEF LS50 is to loudspeakers--one of the best audio values I've ever come across.
Like other DACs by Chord Electronics (all of which, until the Hugo, had been plug-in-the-wall full-size components), the Hugo uses a field programmable gate array (FPGA) DAC, as opposed to off-the-shelf DAC chips. In the case of the Hugo, specifically, it's a custom-coded DAC (with a 26,000-tap-length filter) programmed by designer Rob Watts on a Xilinx Spartan-6 FPGA. The DAC in the Hugo supports PCM files up to 32-bit/384kHz (so that would also include DXD), and also supports DSD (both 64 and 128), and so I think it's fair to say that the Hugo is virtually future-proof.
The Hugo's digital inputs include Toslink optical (24-bit/192kHz-capable), coaxial digital (24-bit/384kHz-capable), and USB. There are actually two USB inputs, a lower power one for mobile phones and tablets that tops out at 16-bit/48kHz, and one HD USB input that opens up the Hugo's full range of format support. The Hugo also can receive audio via A2DP aptX Bluetooth, so you can pair it with your smartphone, tablet, or a Bluetooth-enabled music player.
The Hugo's internal rechargeable batteries will power it for up to 14 hours on a full charge, and its built-in charging circuit will get the Hugo fully charged quickly (around two hours). These robust batteries send much of their power to the Hugo's brawny analog outputs, with a maximum output of 720mW into an 8-Ohm load (and a still hearty 600mW into a more headphone-typical 32-Ohm load). What's also nice is that even with all that power to drive challenging full-size headphones, it is still flexible and quiet enough to be just as competent with very sensitive in-ear monitors. Oh, Hugo, you spoil me!
Despite the Hugo's unorthodox physical design, there's no arguing that it's built like a tank, with its hard-anodized machined aircraft-grade aluminum chassis. My portable gear typically takes a lot of abuse, and so far the Hugo has held up very well, and still looks good as new.
Again, though, what has the Hugo flying off dealer shelves is primarily its sound, which has been greeted with plaudits by just about everyone I've known who's heard it. At once, it's outrageously resolving and relaxed sounding--a combination that's certainly not common, but almost universally desired. Not surprisingly, the Hugo is at its absolute best when I feed it hi-res PCM and DSD material that is well-mastered. I wouldn't characterize it as warm or forgiving, but it has a sense of organic ease that takes the edge off, without actually smoothing away any detail.
And it's not just hi-res material that benefits from the Hugo's touch--I also stream Beats Music and Spotify through it (both of which are at 320kbps at their best), and the Hugo actually makes streaming music sound better to my ears, too--so much so that, with the Hugo, I'm using streaming music services more than ever before. No, it doesn't make my music streaming services sound like the best hi-res you can get from HDtracks, but I will say that there are some DACs that I find less pleasing while playing CD-quality music than the Hugo is when playing some lower-than-CD-quality streams.
Long story short, the Chord Electronics Hugo is a strong candidate to compete to become your dream desktop DAC, and yet it can be thrown into your backpack to be both that dream DAC and headphone amp anywhere you want to take it. As far as portable DAC/amps go that I've used, the Hugo is currently unrivaled when it comes to sonic performance.
From day one, the Hugo has been an absolute joy and marvel to own and use, and has easily become my reference portable DAC/amp, and one of my reference desktop DAC/amps, too.
Thank you, David Chesky, for asking me to give the Hugo a listen at CES. And, yes, sir, it is most definitely worth getting.
"What I like about it is that it is that it excels in NOT sounding like a "hi-fi" DAC, but can be both ultra-detailed yet musical at the same time, without resorting to compromises to achieve that."
Head-Fi Adminstrator / Member / Reviewer
To say I was fired up when I found out Meridian would be entering our space would be an understatement. There are few names in digital audio that command the reverence that Meridian does. I still remember the old Meridian 508.24 CD player very fondly, and have been a fan of just about everything Meridian's made that I've heard.
Meridian's direct appeal for the attention (and the moola) of Head-Fi'ers comes in the form of the Meridian Explorer, a 24-bit/192kHz-capable USB DAC and headphone amp that's about the size of a BIC lighter. Entering a segment popularized by AudioQuest's Dragonfly, Meridian chose to add a few more bells and whistles to turn ears and eyes toward its entrant.
First of all, the Explorer goes a step further than the Dragonfly, in terms of supported sample rates, going to up 24-bit/192kHz, versus the Dragonfly's 24-bit/96kHz. The Explorer also provides more output versatility, with a dedicated analog line out that's combined with a mini-Toslink optical output, in addition to the Explorer's dedicated headphone output. (The Toslink output downsamples 192kHz and 176.4kHz to 96kHz and 88.2kHz, respectively.)
In terms of sound, I give a slight edge to the Explorer over the Dragonfly, with its smoother presentation, and its ability to support my highest resolution recordings (with a driver on Windows, and without the need for a driver on Mac). Headphone-driving versatility is very similar to the Dragonfly, with a relatively black background for even very sensitive IEMs, but yet with enough drive to power most of my over-ear headphones.
The Explorer has a beautifully finished extruded aluminum outer shell with molded plastic endcaps and a rubberized flat bottom surface; and it's assembled by hand at Meridian's UK headquarters. Its sample rate indicator is, in my opinion, more intuitive than the Dragonfly's color-coded one--one light means 44.1kHz/48kHz; two lights means 88.2kHz/96kHz; and all three being lit indicates an incoming sample rate of 176.4kHz/192kHz.
Because the Dragonfly is the smallest of the bunch, it's still the one I tend to tote around the most. That said, I have to give the Explorer the edge in versatility, and the slight edge in sound quality. It's also now the first DAC I turn to when I want 24-bit/192kHz support on the go.
The Explorer is a fantastic first foray by Meridian into the world of headphone audio. Welcome to the world of Head-Fi, Meridian! Please do stick around.
"The combination of price, performance and form factor is very attractive and as an audio upgrade for a travel laptop it's almost a no-brainer. In short, this little device rocks and I have no problems recommending it."
Though we don't currently give out "Product Of The Year" awards, if we did, the Astell & Kern AK240 would certainly be one of the clear frontrunners. Bold in every way--from its feature set to its styling, to its steep price--the AK240 has redefined the hi-res portable music player market, and the demand for it (remarkable demand given the price) has made clear what many high-end portable audio enthusiasts market want in a player.
I think one of the many reasons for the AK240's success is that Astell & Kern made buying their flagship player very simple, the AK240 being devoid of options or variations--there is only one configuration available. Rather than offer different amp options, Astell & Kern chose what I consider to be an excellent amp section that's a solid set of compromises, with enough power to drive overwhelmingly most of the headphones that even diehard portable audio enthusiasts would consider using portably, yet with enough finesse and silence to drive even the most sensitive in-ear monitors with nary a hint of background noise. The AK240 also has a balanced-drive amp section that provides a little more oomph, and, to my ears, provides even better sonic performance.
With their first models--the original, first-gen AK100 and AK120, the latter of which was also a massive success--Astell & Kern has also shown that perhaps using touch screen controls is the best choice for an intuitive, efficient digital audio player user interface (UI). A touch screen can provide more direct access to functions and options that would be far less direct with just buttons, switches and dials.
And it's not just the better screen and other hardware, it's the AK240's improved software that also makes a world of difference. The AK240 underlying software, which represents Astell & Kern's first move to an Android-based system, was a huge step forward, even when compared to the already easy-to-use first-gen AK120. Search was added with the AK240, which I consider a critical function, especially with a device that can hold a maximum of 384GB of data (256GB NAND internally, plus a 128GB micro-SD card). Responsiveness to touch has been greatly improved, too. In fact, rather than simply describe how much better the UI is now, check out this video that shows the AK240's UI in action, closeup.
Like the first-generation Astell & Kern players, the AK240 supports up to 24-bit/192kHz PCM, but now uses two of Crystal's flagship CS4398 DAC chips (instead of the Wolfson WM8740 DAC chips in the previous ones). The AK240 now also natively supports DSD decoding (with its additional on-board XMOS chip), unlike the AK240's predecessors, which internally converted DSD to PCM, before conversion to analog. As with the other Astell & Kern players, the AK240 can also be used as a hi-res USB DAC/amp (but with native DSD support now), which furthers its appeal as an all-in-one, especially given its strong performance in that additional role. Also, like the first-gen models, the AK240's single-ended 3.5mm headphone output also serves as the analog line-out and the optical digital output.
While its maximum of 384GB of on-board storage (again, 256GB NAND internally, and up to 128GB more with a micro-SD card), the AK240 has more storage than any other portable music player I'm aware of. When you're storing huge hi-res music files, though, you can never have enough. One feature added to the AK240 that helps the user transcend storage limitations that I think is absolutely awesome (and that I use a lot) is the AK240's MQS Streaming feature, which provides connectivity to the AK240 through the network. I have two main computer audio systems (one at home, one at the office), each of which contain far more music than can be stored directly on any portable music player, including the AK240. Astell & Kern provides a free app called MQS Streaming Server that you install on a computer on your wi-fi network, and that allows the AK240 to losslessly stream music from your main systems--yes, including hi-res PCM and DSD. So now, at home and at the office, my AK240, with wi-fi streaming, has access to terabytes of music to play, not just the 384GB on the device itself. For me, to have wireless access to my entire< music collection (whether lossy MP3's, CD-quality rips, up to 24/192 PCM, and DSD) when I'm at home and at work is huge; so, again, I use MQS Streaming a lot.
By the way, another key benefit of wi-fi connectivity with the AK240 is OTA (over-the-air) system updates. In the time I've had the AK240, numerous updates and improvements have been released for it by Astell & Kern, who has been very proactive in terms of constantly improving it, and all of these firmware updates were available and installed via OTA updating, and are available to the user the moment Astell & Kern releases them. What's also nice--so that you don't have to keep searching for updates--is that the AK240 automatically checks for available firmware updates when it has a wi-fi connection, so you don't have to.
The AK240's chassis is hewn from a block of duralumin, machined and sculpted into a beautiful, angular form that is fantastic in the hand, particularly if you're controlling it right-handed, with the AK240 held in your left paw. It is also has a back panel constructed of genuine carbon fiber. No other digital player I've used so far comes close to the level of fit and finish--not to mention the remarkable vault-like solidity--of the AK240. If you've only seen the AK240 in photos, its odd angles can make it look larger (and stranger) than it is in real life. It's actually very compact, and, again, is drop-dead gorgeous, in real life. The AK240 comes with a form-fit, finely constructed Italian leather case by Buttero.
Now this brings me to one of my gripes with the AK240, and there are only a couple of those. I am not a fan of Astell & Kern's choice to use a 2.5mm jack for balanced output. While I haven't had any major issues with the 2.5mm balanced plugs yet, I find these plugs too tiny, and not exactly the most secure, durable plug for mobile use. I've found the 2.5mm plugs pop out with much less force than necessary to similarly dislodge the more standard (and substantially larger) 3.5mm mini plugs. I think some type of mini-XLR configuration would have been the more ideal choice.
My only other grumbles with the AK240 are its relatively short battery life when playing hi-res PCM and DSD files and the inability to install Android apps (even though it's Android-based). While I've seen close to ten hours of continuous playback time with MP3's and CD-quality files, I'm only getting around half that when playing back strictly hi-res PCM and DSD. This is somewhat understandable given the very compact size of the AK240 and the increased processing power needed to decode hi-res files, but, still, I'd like more juice, and would have gladly given up some of its compactness for more battery life. I normally carry portable battery chargers, and am at least thankful that the AK240 (as all of Astell & Kern's players) charges via a standard micro-USB jack.
As a frequent user of music streaming services--namely Beats Music (formerly MOG) and Spotify Premium--I wish I could install their apps on the AK240, as I can with the Sony Walkman NW-ZX1. Though the AK240's system software is Android-based, the OS implementation and software stack is very custom, and, unfortunately, rather closed.
As for its sound, the AK240 is, overall, the best all-in-one portable music player I've yet heard. While its sound and drive doesn't quite reach the level of something like Chord's Hugo, the AK240 is obviously the more complete mobile device, able to carry a large quantity of music on-board, and providing a fantastic user interface to access and control it all--a super-compact, true all-in-one portable system that requires no additional external transport, DAC, or amp. And, still, its sound is very much that of a high-end digital audio device, and, overall, the best, most versatile portable digital audio player I've yet heard. Its sound is highly resolving, very uncolored--neutral, but not dry. Soundstage and imaging with the AK240 is exceptional, not just for a portable audio player, but for any digital component--able to convincingly convey all dimensions and precise image placement with excellent recordings. With its balanced output, drive and imaging improve further, so contact your favorite cable maker to have your favorite on-the-go headphones outfitted with cables terminated to use the AK240's balanced output--you'll be thankful for it, and it'll certainly help you wrangle as much of the performance you paid $2500 to get.
Because of its extreme portability, the AK240 will probably be very commonly used with high-end, super-sensitive in-ear monitors. Like all Astell & Kern players I've used, the AK240--in terms of self-noise--is as quiet as a tomb. Even my most sensitive in-ears are unable to touch the AK240's noise floor, making it one of the quietest components I've used, portable or full-size, and that's a big deal to me.
Because I'm often on-the-go, the Astell & Kern AK240 has, since its release, been my most-used audio system. It's so good, so capable, so thorough, that I don't really think of it as a portable music player as I do an ultra-portable high-end transport/DAC/amp system. It has replaced my rubber-banded-together stacks of portable components, and is truly pocketable. It is expensive, yes. But, currently, there's nothing quite like it, which is why, even at $2500, it has been flying off dealer shelves just about as fast as Astell & Kern can manufacture them.
After having said all of this I want to say one more thing about the AK240--something I've not specifically seen stated about it before. One of the main reasons I use the Astell & Kern AK240 so dang much (other than the fact that it accompanies me everywhere I go) is because, regardless of format--256kbps MP3 or AAC, CD-quality 16/44.1, 24/96, 24/92, DSD, etc.--it just plays music, fuss-free. I can shuffle through my my music collection without worrying about what kind of file I'm playing--whether playing from internal storage or streaming via MQS Streaming, the AK240 can seamlessly bounce between (and natively decode) all formats, bit depths, sample rates, without needing any intervention, without even needing to look at it. My music collection is all over the place with regard to file types and quality, and sometimes I just want to hit the "play" button and not worry about much else.
"Where the AK240 excels, I feel, is that as a complete self-contained package - sonics, capacity, usage, functionality, visual and feel aesthetics - the AK240 is a winner. It sits in one's pocket unobtrusively, it's basic functions are easily accessible with external buttons, it can function as a DAC/Amp with a notebook, it supports balanced headphones out, it supports line out, it has copious amount of storage, it can stream high quality music wirelessly, it even supports online download in countries where the service is available, and it doesn't sacrifice quality in doing all these things."
Head-Fi Moderator / Member / Reviewer
Written by Jude Mansilla
Class D amp circuits are known for high efficiency, and are becoming increasingly popular for use in loudspeaker-driving amplifiers. They run much cooler, consume less energy, and so a powerful Class D speaker amp can be housed in a rather small chassis. How can those characteristics play favorably in the context of a portable headphone amp? The new iQube V5 portable DAC/amp combo answers the question.
From its rechargeable 2500mAh lithium-ion battery, the iQube V5 can play for over 30 hours when using its digital input, and over 70 hours when using its analog input. It is alsoverylight, weighing 190 grams--less than half the weight of the Chord Hugo and Aurender Flow (two of my other reference portables). The iQube V5 is an ideal traveling DAC/amp combo.
In terms of its rated output power, the iQube V5's amp can output 160mW into 16Ω, and 80mW into 32Ω, and 12mW into 200Ω. While those numbers don't read as monstrous, I've found (as I have with some of my Class D speaker amps) that the iQube seems to have more oomph than those numbers suggest. I've been using the iQube V5 quite a lot recently to drive the Sennheiser HD 800, Sony MDR-Z7, HiFiMAN planars (but not the HE-6), and Audeze's headphones. In terms of self-noise, the iQube V5 is quiet enough to use with my most sensitive in-ears. And considering most of my ultra-sensitive IEMs are multi-armature designs, the iQube V5's low output impedance (<0.1Ω at 5kHz, and <1.5Ω at 20kHz) is ideal for them. This kind of flexibility is fantastic to have in a portable, especially when it comes in a device that can run as long as the iQube V5 can.
In terms of its sound quality as a portable DAC/amp combo, the iQube V5 has excellent resolving power, and a great sense of drive. On the one hand, it's actually very fun to listen to; on the other, I consider its level of performance reference-class for a portable DAC/amp at its price. Will I be adding this to my travel audio arsenal? Oh, you bet.
The first thing many people wanted when they heard about the Calyx M was an AK240-level device without the price tag. Good luck! But in all honesty, if there is another company (other than Sony) that might be capable of invading the market with something competent, it would be another Korean company. Having owned a Calyx DAC in the past, the DAC 24/192, I was curious to find out how their portable would fare, so when the CEO of Calyx introduced himself at the May 2014 headphone festival in Tokyo, I didn’t hesitate to ask for a loaner unit.
Physically large compared to the other DACs, it makes the chunky AK240 seem quite small. Two memory card slots: one microSD and one SD on top, and the unique sliding magnetic volume control on the size dominate the external features besides the screen. That screen is bright and clear, making viewing of the custom user interface (built over Android) to be a pleasure.
That beautiful interface one navigates primarily by swiping left or write to get to the music and Jukebox feature respectively. Menus at the top access information and settings for one, and the currently selected album or playlist on the other. Centrally, of course, is a playback screen with the play/pause control overlaying the album art and quick access to repeat and shuffle available, along with track information. This makes the Calyx M’s user interface very quick to pick up and use. Pressing and holding on tracks, for example, allows them to be added directly to the main Jukebox playlist, or another playlist as desired.
The downside to the user interface is it is a bit slower than those of the AK DAPs and at power-on the SD cards can take a couple of minutes to be scanned and loaded if they are large. There have also been complaints from users about battery life only lasting 4-5 hours of playback (3.5 hours with DSD and the screen off). However, Calyx are working steadily on improving the software, so I’d expect in time things to get better.
Sound-wise too, the performance is very good, if a bit behind the AK240 and seems to be a bit “darker” in presentation. Music comes through cleanly with a wide soundstage whether using IEMs or full-sized headphones, for which the Calyx M is more than capable of driving. The Calyx M with the HD-800 and Audeze LCD-X, while not driving them with the authority of a desktop amp still managed to do a good job with the sound, the main thing lacking was volume level on the tracks from David Chesky’s Open Your Ears album. The gain level was far better suited to IEMs. However, gain settings exist in the settings under “Impedance matching”. Putting the M on the highest setting improved the performance with the HD-800s for example. Used as a DAC via USB, it was somewhat flatter-sounding and dull compared to using it as a DAP, with better USB cables and Schiit Wyrd improving things.
Overall the main thing is that the Calyx M will be giving the Astell&Kern DAPs a good run for their money, if not quite, in my opinion, the AK240. If you don’t mind the somewhat large size (think of a large Android phone, but much thicker) and are interested in headphone powering ability over battery life, this is a DAP well-worth considering.
Some of the biggest news in this category is that Sony entered the iDevice DAC field. Yes, you read that right--I said SONY. Their entry is called the Sony PHA-1 (around $600), and it's very clear Sony's not messin' around. The PHA-1 is one of the best built, and easily the best looking (to my eyes), portable amp or DAC I've ever seen.
And check this out: For the PHA-1, knowing people would need want to pair it with an iPod or iPhone, Sony built a rail into each side of the top panel to accept included silicone hooked bands (that hook into the rails). This eliminates the need to carry big rubber bands, or the need for Velcro strips. (And, in a nice touch, the top surface has two rubber strips running from front to back to help prevent scratches. Details, details!
The Sony PHA-1 is built to exacting standards, using (if I recall correctly) a six-layer 35μm-thick copper foil PCB, with tremendous attention paid to the layout of the analog and digital circuits, to minimize internal electrical noise interference. And much attention was paid to shielding to help minimize external interference. I mention all that only because, more than any other portable amp or amp/DAC, the PHA-1 seems impervious to noise, even when I'm using my radio-packed iPhone on top of it.
The Sony PHA-1 is also a 24/96-capable USB DAC! And it's amp? Two gain settings, and its black background, make it suitable even for my more sensitive IEMs. Its high-gain mode very nicely drives most of the headphones I bring with me.
Unfortunately, PHA-1's battery life is just 10 hours if you use its analog input, and only 5 hours in iDevice DAC mode. In USB DAC mode, it runs off USB bus power, and charges its battery. Also, the PHA-1 offers no digital pass-through.
With one of the best industrial designs in the segment, Sony quality, and wonderful sound, I strongly recommend you check out the Sony PHA-1.
Joining the Sony PHA-1 in March 2014 is the Sony PHA-2. The PHA-2 offers several improvements versus its older sibling, the new PHA-2's DAC supports up to 24-bit/192kHz (versus the PHA-1's 24/96). The PHA-2 also supports DSD 2.8/5.6MHz! (The PHA-1 doesn't support DSD.) The PHA-2's battery is rated for 17 hours using analog input, or 6.5 hours with the digital inputs (versus the PHA-1's 10 hours and five hours, respectively).
If I had to distill Sony’s personal audio mission in recent years, down to just one word, that word would be evolution.
Ongoing improvements, through successive product iterations, are happening throughout Sony’s entire range of personal audio offerings, from headphones to IEMs to DAPs. But the one product line that personifies this spirit of evolution, more than any other, is their PHA-series of portable DAC/amps. Since its debut in late 2014, the Sony PHA-3 has been steadily winning over the hearts and minds of Head-Fiers near and far, and it’s easy to see why.
Like the PHA-1 and PHA-2 before it, the PHA-3 sports impeccable build quality, remains impressively quiet with a pitch black background, is compatible with iOS devices, and drives most headphones with dexterity and authority via its low or high gain settings. And like the PHA-2, it’s also capable of high resolution audio, including single and double rate DSD.
To that, the PHA-3 adds an impressive list of new features that any discriminating Head-Fier would approve of wholeheartedly. The PHA-3’s DAC section has been upgraded to an ESS ES9018 from the Wolfson WM8740 found in the PHA-2. A new XMOS chip enables Sony’s DSEE HX digital signal processing algorithms to upscale lossy audio files. And yes, DSEE HX actually works. The PHA-3’s battery life now provides up to 28 hours of play time via analog input (i.e. using the PHA-3 as an amp). That’s 11 hours longer than a PHA-2, and 18 hours longer than a PHA-1. It also includes a new optical input for those who might not be keen on using USB. And finally, it is now capable of balanced drive via dual 3.5mm TRS jacks. It is this last feature that truly makes the PHA-3 an outstanding unit.
When a PHA-3 is paired with Sony’s MDR-Z7 headphone or Sony’s XBA-Z5 in-ear monitor - via optional Kimber Kable balanced cables - and you play high-resolution or DSD files through that signal chain, it becomes very clear that Sony voiced all of these components together as an ecosystem. The sound quality of such a rig is, in a word, exceptional. Playing through Michael Jackson’s Thriller album in single-rate DSD (available from Acoustic Sounds), we are rewarded with a balanced, detailed and dynamic presentation cast amidst an expansive soundstage.
That said, the PHA-3 does fall short of greatness in several respects. At $999 USD, the price can be a bit steep for some. This is especially true if one won’t also make the additional investment in an MDR-Z7 or XBA-Z5 (along with its respective Kimber Kable balanced upgrade cable) in order to take the PHA-3 to its fullest potential. Secondly, the PHA-3 won’t charge and play at the same time. By itself, this is not a dealbreaker. But taking into consideration that the PHA-3’s battery life is only 5-hours long when using its digital inputs (i.e. using the PHA-3 as a DAC+amp), and can take up to 15 hours to fully recharge, this amount of device down-time can be rather annoying. And finally, the PHA-3 can’t output balanced audio when you’re just using the analog input.
Nonetheless, the PHA-3 is a significant upgrade from the PHA-2. It advances the PHA-series by retaining the best that its progenitors had to offer, while introducing new and worthy features. And of course, as the cornerstone of a hi-res ecosystem, it sounds very, very good. Exceptionally good.
Someday, in the next evolution, I hope that Sony will release a PHA-4 that addresses all of the issues above. In the meantime, Sony has yet another winner on its hands with the PHA-3. I am enjoying it immensely - especially with an MDR-Z7 or an XBA-Z5 and their respective Kimber Kable accoutrements - and would happily recommend it as both a portable and a desktop DAC/amp.
The Fostex HP-P1 was released in 2011, and has been a constantly sold-out hit. What makes the HP-P1 so popular is the fact that it does iDevice DAC duty, and it has a built-in headphone amp. With three gain settings, the amp is quite versatile, and can very nicely drive most headphones that you'd want to use portably. The single-unit portable iDevice DAC/amp combination has made the HP-P1, paired with a 160GB iPod, a frequent companion of mine. (We discussed the Fostex HP-P1 in Episode 011 of Head-Fi TV.)
"I reckon the HP-P1 is a great piece of kit, if not an amazing one. I reckon it hits its price almost exactly in terms of features, capability and sound quality"
I've seen a lot of discussions about FiiO on Head-Fi in recent years. However, I’d somehow made it through to the early part of this year without ever having tried anything made by one of the brands taking Head-Fi by storm. Because one of the last things I need is another headphone amp, perhaps the FiiO collection--all of which is affordable, and some of which is super affordable--simply struck me as something I didn’t personally need in addition to all the more expensive, higher-end portable amps strewn about my home and office.
Fast forward to CES 2013, to a time when FiiO was already well established as an immensely popular brand on Head-Fi. I had a meeting with James Zhong of FiiO. It was just a casual meeting during which James introduced me to the FiiO line. As the meeting concluded, he gave me a FiiO E12 Mont Blanc portable headphone amp.
It was probably a few weeks after returning from CES that I finally charged the FiiO E12 up, and started using it. I started with its low-gain (+0 dB) setting, and plugged my most sensitive IEMs into the E12. Relative silence. I played music, and was treated with a wonderful sounding amp that had me double-checking it for Ray Samuels Audio or HeadAmp markings. I tried a few other headphones with it, and, with aplomb, the FiiO E12 Mont Blanc drove them all.
In its high-gain setting (+10 dB), the FiiO E12 was making easy work--and beautiful driving--of my Audeze LCD-2 and LCD-3, and my HiFiMAN HE-400 and HE-500. And the HD 800? You bet. With the exception of a few portable amps by ALO Audio and Ray Samuels Audio, I’ve not had much luck with finding a portable that I liked with the HD 800. Until the E12, that is. Not only did the E12 drive the HD 800, its bass boost (with its emphasis peaking way down low) gave the HD 800 a kick up the fun scale--this is something I’ve also enjoyed with the ALO Audio Mk3-B that also has a bass boost circuit (a very nice adjustable one).
Okay, so the 130-buck E12 was inspiring some derring-do, and I reached for the HiFiMAN HE-6. And the hits just kept on coming. Bass boost with the HE-6? Try it, 'cause it's real fun.
How does the E12 compare to the best of my portables? My SR-71B from Ray Samuels Audio, for example, is still the more impressive, more hi-fi driver of the HE-6 and HD 800 (using its balanced output)--bigger soundstage, blacker background, more dynamic. But that SR-71B is $650.00. My HeadAmp Pico Slim is still the more impressive, purpose-built amp for my top-tier IEMs, but at $399.00. The FiiO E12 is a $129.00 steal of an amp that brings together some of the qualities of my favorite portable amps, in a very well-built, full-featured package. (I haven’t even mentioned the fact that the E12 also has a crossfeed circuit!)
My only real quibble with the FiiO E12 Mont Blanc is some sensitivity to radio frequency interference. If I'm using my iPhone as a source, for example, I'll occasionally hear interference and hash through the E12. This is most noticeable with sensitive in-ears, and also with some sensitive over-ears. It hasn't been bad enough to prevent me from pairing it with my iPhone, but it's not something I'm experiencing with most of my other premium portables. Also, since James gave me this E12, FiiO has since modified the bass boost circuit, moving the peak from 20Hz to 50Hz, so your results with bass boost may be different than mine.
If you’re looking for a do-everything portable amp--something you can use with your IEMs and hard-to-drive over-ears alike--I’ve not used anything else I’d recommend more heartily at anything near the price of the FiiO E12.
I may have been late to the FiiO bandwagon, but I’m definitely on it now.
Sony Walkman NW-ZX1
With all the hi-res-capable music players out there by the likes of HiFiMAN, Astell & Kern, FiiO, iBasso, Calyx, and others, the Walkman NWZ-ZX1 by electronics giant Sony sort of squeezes in, ironically, as a boutique entry in the space. This is no doubt helped along by the fact that the NWZ-ZX1 is not currently available in the U.S., and I've seen no signs of that changing.
Despite the fact that it's swimming in some seriously shark-infested competitive waters, Sony's current flagship Walkman makes up for its couple of key shortcomings with an excellent Android-based UI (user interface), and--unlike the Astell & Kern players--the ability to install standard Android apps, which allows me to stream music with Beats Music (formerly MOG) and Spotify Premium. For purposes of music discovery, being able to use streaming services is a big deal to me. Keep in mind, though, that the NWZ-ZX1 is not a mobile phone--though its four-inch 854 x 480 screen does make it look and feel a lot like one--so you'll need a wi-fi connection for streaming.
The Walkman ZX1 can play every music file type I've thrown at it so far, including (with a recent firmware update) DSD (DSD64). (I do believe its DSD playback is facilitated through conversion to PCM first.) Its battery life is rated at up to 32 hours of play time with 128kbps MP3 files. While that sounds very generous, I've found the Walkman ZX1's battery life when playing a mix of CD-quality and hi-res tracks (hi-res PCM and DSD) to be much shorter than that, and more comparable to (and maybe a bit longer than) the Astell & Kern AK240.
The Walkman NWZ-ZX1's machined aluminum chassis with its leather-like backside is beautiful--elegant, yet striking. The aluminum is finished in a combination of brushed and bead-blasted finishes, to emphasize the chassis' beautiful beveling. The very top edge of the Walkman ZX1 appears to be made of plastic--made to look like the brushed aluminum around it--which I would assume is to improve radio performance (a detail I wish Astell & Kern had considered for its metal-bodied players, whose wi-fi reach I've found can drop off quickly with distance).
One strange thing about the Walkman ZX1's design, however, is its... well... its butt. (That's what I call it anyway.) The ZX1's lower 1/3 is thicker than the top 2/3, all of it protruding (smoothly) out back. This bumped-out bit means the Walkman ZX1 sits awkwardly when you set it down on its back panel, seeming to lean away from you. It also means that Sony saw fit to include a spacer with the Walkman ZX1, so that it can lie flat on top of something else (like, for example, Sony's own PHA-1 and PHA-2 DAC/amps). Admittedly, this helps the Walkman ZX1 feel good in the hand, but I'd rather it was able to lie flat on its back panel without the spacer. Yes, my Walkman has a leather-clad butt.
One key thing on my wishlist for the Walkman ZX1 is expandable storage. It comes with 128GB of internal storage, and no slots for expansion. This might sound like a lot of storage to some, but if you're going to be taking advantage of its hi-res capabilities, 128GB can fill up fast.
The amp section in the Walkman ZX1 is digital (Sony calls it the "S-Master HX digital amplifier"), and, in terms of background noise, is dead silent (to my ears) with most of my headphones. However, some of my most sensitive in-ears will uncover a very faint background hiss--very faint--that is generally quieter than room noise, and never audible to me during music.
Overall, the Walkman NWZ-ZX1's sound siganture is detailed and punchy, and it has enough to drive to power every headphone I regularly use portably, up to and including the MrSpeakers Alpha Dog, which, in terms of sensitivity, is about as much headphone as the Walkman ZX1's digital amp can comfortably push. It fares better with the more sensitive OPPO PM-1, which is a headphone pairing for the ZX1 that I'm particularly fond of. Most of my Walkman use, though, has been with my JH Audio Roxanne (customs), FitEar MH334, and Ultimate Ears Reference Monitors. To my ears, the ZX1 does not quite reach the heights of fidelity and sound quality I'm getting from the Astell & Kern AK240, but, for its features and its price, the sound quality I get from the Walkman is excellent.
In terms of usability, though, the Walkman scores gigantic points by allowing for the installation of standard Android apps, which, again, allow me to use streaming music services with it, or even (as I've been doing) to watch FIFA World Cup football on it via ESPN's streaming app. And, right now, there are no other hi-res-capable portable music players at Head-Fi HQ that'll do that.
It's not surprising to me that, despite its quirks, the Sony Walkman NWZ-ZX1 has so many fans in our community. I certainly am one of them.
"The ZX1 definitely grabs my attention more easily as it's so clean cut, precise, and clinical... I'll use the ZX1 when I'm on the move to 'n fro work, walking around whilst shopping, or at the local Starbucks whilst escaping from paternal duties."
Back when I was still spinning CD's to play music, UK outfit Arcam made some of my favorite reasonably priced disc spinners. As for most of you, time's have change over here, and I pretty much only spin CD's nowadays to rip 'em. With the rPAC, Arcam has reentered my life with no moving parts.
The Arcam rPAC is a lovely little USB DAC/amp device powered only by USB power, so no additional power cords or adapters are needed. It's 24-bit/96kHz capable, and its USB implementation is asynchronous mode. Outputs include a headphone output on the front (of course), and RCA stereo outputs out back. Volume is adjusted with two buttons atop the rPAC, and in fine increments.
I use the rPAC solely from its headphone out, and it's a very nice piece for driving everything from my sensitive in-ear monitors to many of my favorite reasonable-to-drive over-ears. It doesn't, however, have the drive, the authority, to drive (to my satisfaction anyway) my more challenging headphones.
The rPAC's sound signature is quite neutral, and just revealing enough to keep "polite" out of the pool of adjectives I'd draw from to describe it.
Because it's powered only from USB bus, and because of its very small footprint, I've classified the Arcam rPAC under our portable category. However, with its metal chassis, it has a nice heft to it; and its flat, rubberized base keeps it put; so my use of the rPAC is more along the lines of a desktop DAC/amp that just happens to be pint-sized. I usually keep it at one of my desks on which space is always at a premium. I have also taken it with me on a couple of trips, to serve as my hotel desk DAC/amp.
The rPAC is simple and versatile, sounds excellent, and has been a wonderful way to reconnect me with Arcam, one of my favorite audio brands.
Written by Jude Mansilla
I fully admit I'm a Fostex fan. They're like a corporate version of the intensely passionate Tokyo DIY portable audio scene, but with a lot of engineers and the facilities to productize what they dream up. While guys like me were lashing together stacks of airport-security-eyebrow-raising portable rigs, and wishing for a one-chassis version of it all, Fostex was, too--only they were able to develop and manufacture the wish with the Fostex HP-P1 (back in 2011). Well, it seems like more recently someone at Fostex was listening to his portable rig one day, and hankered for a shot of the kind of harmonic glow and richness that good tube gear can do so well, but didn't want to give up portability. Voila, the Fostex HP-V1 portable tube hybrid headphone amplifier!
The HP-V1 has a 6N16B-Q vacuum tube input stage, and a solid state opamp-based output stage. Inside are also custom Fostex large film and elecrolytic capacitors based on their work in loudspeaker engineering. Maximum rated output for the HP-V1 is 200mW into 32Ω, so there's enough to power most of what you're likely to use portably (but you can leave the inefficient HiFiMAN HE-6 at home). Though the HP-V1's specs don't give the specific output impedance, they do say that it's appropriate for use with headphones >16Ω. The rated runtime from its internal lithium-ion rechargeable battery is about 10 hours from a full charge, and while I haven't specifically measured that, it seems a reasonable estimate.
Because it runs rather warm, the HP-V1 is encased in a ventilated black metal chassis that looks a bit like the HP-P1's chassis, but in matte black, and with very cool vent slots and fins morphed in. In my opinion, it's a very attractive design, and feels well built. The HP-V1 weighs 390 grams (13.75 ounces), so while's no brick, it's no feather either.
Of course, the first headphone I tried the HP-V1 with was Fostex's own TH900, one of my favorite dynamic headphones. (The HP-V1 was being fed by the Chord Hugo.) And unquestionably, there's a beautiful mid-focused lushness, but without changing the TH900's overall tonal balance. Compared to the Chord Hugo directly from its headphone output, the HP-V1 is not as resolving overall, but sometimes I just have a taste for the a tube-induced sumptousness in the mids, and I'll take the occasional tradeoff of giving up a bit of overall resolution for that. The effect was the same with the Sennheiser HD800--also one of my favorite headphones, and one of my accuracy references--which I was happy to find the HP-V1 was able to drive to above moderate volume levels without any audible strain (it would likely go louder, but I wouldn't). In fact, from headphone to headphone, the HP-V1 was consistent in its abilities--although, to my ears, the HiFiMAN HE-6's inefficiency was simply too much of a problem, to my ears, and the romance wasn't present for that one.
As for in-ears, the HP-V1, in terms of its noise floor, is quiet--but not dead silent--with sensitive IEMs. Also, with sensitive IEMs, you will likely hear tube microphonics (ringgggg) when the amp is tapped on or jarred. Still, none of this is so problematic that you couldn't use in-ears with the HP-V1 in a pinch.
With the HP-V1, I have no real complaints. I know what it is, and I know what it isn't, and I use it accordingly. One thing I did notice is that when I flip mine upside down (and back again), I can feel what is probably the battery moving just a little bit. At the Tokyo Headphone Festival, the ones Fostex had at their exhibit were doing the same thing, and I don't think it's any reason to be concerned, but thought I should mention it.
I love the HP-V1. In the collection of portable amps we have here at Head-Fi HQ, it is certainly among the more unique ones. It's a little bit of sonic romance on-the-go. It sounds to me like what a portable headphone amp might sound like if Saul Marantz was still alive to design a portable headphone amp.
It has an excellent CEntrance-designed 24/192 DAC in it that I can use with a variety of portable source devices, or with a computer. It has three output impedance settings you can select from (1Ω, 2Ω and 11Ω) which allows me to evaluate how different output impedance levels might impact a headphone sonically. It has three gain levels, the lowest of which is quiet enough to drive my sensitive in-ears; the highest of which has enough gusto to drive the HiFiMAN HE-6. It has both single-ended and balanced headphone outputs, and (depending on which model you choose) an optical digital output that allows me to engage still other DACs. It has extremely well implemented adjustable bass and treble controls. And it's portable, and provides over six hours of battery life.
Yes, everything I described above is portable. It's not just an audiophile's dream device for portable listening pleasure, it's an audio reviewer's fantasy as the centerpiece of a reviewing rig that can go anywhere.
"...power it has aplenty, presenting a wide and spacious sound through everything from low-impedance and low-sensitivity planers through to high-impedance HD-800s, with audio sourced from either a computer through its asyncronous USB input, or its second input, which at the time of purchase you have to choose either an iDevice-compatible USB socket or an optical digital input."
I love CEntrance's HiFi-M8, but it's on the large side of a portable DAC/amp nowadays. Also, one of the tradeoffs of the HiFi-M8's ability to drive even the hardest-to-drive headphones is that though it is quiet (in terms of self-noise), it's not dead silent with my most sensitive in-ear monitors.
Enter the CEntrance Mini-M8. The Mini-M8 carries over almost every single thing I like the HiFi-M8 for, but with less weight, a smaller size, much longer battery life, DSD support, stepped volume control for perfect channel matching even at the lowest volume levels, and a noise floor low enough that my most sensitive in-ears can't reveal it to me.
When I'm on the go, I'm rarely in need of the brute force of a desktop amp, usually carrying in-ears, or over-ear headphones no harder than moderate in terms of power demands. In other words, overwhelmingly most of the time (for me), giving up a lot of the HiFi-M8's output power to gain all of those advantages is well worth it. Still, though, at 330mW per channel output in balanced mode, and 160mW per channel output in single-ended mode, the Mini-M8 still packs a solid punch.
In short, given my on-the-go lifestyle lately, the CEntrance Mini-M8 is everything I need from the HiFi-M8 and then some.
"Mini-M8 still offers incredible transparency, without any coloration. You'll hear all recording's details, all instruments, every notes and smallest nuances of sound"
Using my phone as my primary music player is not something I am keen on doing.
For most of us, the iPhone 6’s battery barely lasts a full work day under normal usage. Texting, navigation, social media, taking pictures or videos, emails, and that dreaded phone app with a scammer on the other end telling you they have a tax refund in your name - they all suck up precious power, leaving little left over for music playback.
In addition, I don't want my music player to multitask. Call me old-fashioned, but I prefer a dedicated music player that sounds great, and won’t stop the music to notify me that someone has tagged me on Facebook or Twitter.
And finally, as a self-proclaimed audiophile, I demand good sound quality from a music player as well. So even if I were to use my phone as a music player, I would have to enhance the sound quality by strapping a portable DAC/amp to it. That’s not sexy. Stick that sandwich of electronics in your pants pocket, and that bulge might get you some ugly looks.
This is where the Astell&Kern's new AK Jr. saves your public image and preserves your cool factor. Like every other Astell&Kern music player, the AK Jr. is visually appealing and very well made. The AK Jr. is the thinest and lightest AK player to-date. It’s so small, it might even fit in the coin pocket of some men’s jeans. To me, the Jr. is damn sexy!
First and foremost, the AK Jr is a hi-res music player boasting a Wolfson WM8740 DAC with support up to 24/192kHz, DSD to PCM conversion, and a high-powered headphone amplifier. Those are specs you won’t find on any of Apple’s current or past music players.
With my reference IEM the Sony XBA-4 (8 Ohms, quad drivers, balanced armature), the AK Jr. did the heavy lifting without a flinch. This IEM is difficult for a lot of the digital audio players and amps that I’ve tried. They would either clip at above normal volume level or there would be a good amount of background hiss. The AK Jr. is silent and had plenty of power to drive the Sony.
In the sound department, there is nothing junior about the new AK Jr. Lovers of EDM and modern Pop music will enjoy the tight and authoritative bass. Midrange is buttery smooth, but not lush or slow. Female and Male vocals have nice decay to give the listener a sense of intimacy, like a private concert. The highs are not fatiguing regardless of volume level.
The one thing I would like is more transparency, but I think my ears are accustomed to the AK Jr.’s bigger brother the AK120II. The AK Jr. doesn’t out perform the AK120II, but it might be really close to the AK100II. I don’t have an AK100II on hand so I can’t do a comparison. Jr.’s form factor and weight wins out for me though if I had to choose from its larger siblings or any other music player.
The non-feature I love most about current AK music players is it doesn’t run a full version of Android, which means no third-party apps and no web browser. There are zero distractions that will remove me from enjoying music.