Pros: Great SQ, Lots of storage capacity with 64GB already on board, very usable UI, Drives the HE-500!!
Cons: It is expensive
I have owned the AK120 since September and listen to it every day, several hours a day. I use a variety of headphones depending upon where I am. When I'm home, I prefer my HiFiMan HE-500 Orthodynamic cans or my JH Audio 16 Pro and when I'm out I generally use my closed back Shure SRH-940, UE 5 Pro or my custom fit ER4 MicroPro. I have used it with a variety of amplifiers though it really doesn't need external amplification to drive any of the headphones I listed to a reasonable volume level. I was in fact surprised to discover just how good it sounded with the power hungry HE-500's and with all the other headphones, it could drive them way beyond my listening threshold and I like my music loud. The HE-500 being Orthodynamic do benefit from some extra amplification however, they are quite good just with the AK120. When I'm out I leave my amps at home and carry my AK120 on my belt in a small case, the Swiss Gear - Jasper Small Camera Case-Black, is a perfect fit and adds extra protection, available at Best Buy for $4.99 (Model:
Battery life has been surprisingly good as I generally use it daily for at least 1-2 hours, sometimes more and only need to charge it weekly so I figure I'm getting about 12 hours of listening time and haven't run it down to zero once. The UI is really intuitive, very responsive and easy to use. Even though I have the unit almost fully loaded with FLAC files, about 150GB so far, it still responds with little lag. I have both microSD slots loaded with SanDisk Ultra 64GB micro SDXC cards with the factory exFAT file system intact and the AK120 see's all of my music files and metadata with no problems whatsoever. I loaded my music files onto my cards through Windows 7 by just copying the folders onto the SanDisk cards using a USB3.0 card reader and it worked flawlessly.
Another benefit to the AK120 is the fact that it connects to my computer's USB port (USB2.0 only so far) which allows me to use is as an external DAC to listen to all the music I have stored on my computer and it sounds incredible through my headphones. I also connect it to my home theater system directly from the AK120's headphone jack to an aux input and the sound is again - amazing, better than my DVD player and I no longer have to look through the hundreds of CD's I have to find what I want to listen to. I have to say that I was skeptical before I bought it because it costs so much and I wondered if it would indeed prove to be worth the expense. Given Amazon's great return policy and the fact that there are not many others in it's class to choose from, I decided to try it and am very pleased.
The Astell&Kern AK120 measures 2.33"W x 3.50"H x 0.57"D and weighs only five ounces. It's main interface is through a sharp and responsive 2.4" QVGA IPS Touchscreen while on it's right side it has a analog volume control wheel and on the left side, three tiny control buttons for back, forward, and play/pause. All the controls function fully even when the screen is off and a brief touch to the power button brings back the display while another brief touch darkens it again. Across its top are the earphone/optical-out port, an optical-in port, both 3.5mm and the power button. On the bottom you will find a micro-USB port and a sliding door which covers the slot for the two microSD cards. It also comes with an well crafted Italian-leather carrying case that has cutouts for all the aforementioned controls except the microSD slot which remains covered. The device can be used at all times while in its protective leather case only requiring removal if you need to change or add an SD card.
The dual-DAC AK120 holds 64GB of audio files via its internal memory and can add 128GB more via two 64GB microSD cards for a total of 192GB (180GB actual). It's equipped with two Wolfson WM8740 DACs each running in mono-mode that handle virtually any format including DSD via new firmware released in July and has a nifty, ergonomic design that's attractive and simple to use. Best of all, it sounds great with all types of music, its dual DACs providing fabulous resolution, speed, and great sense of space. The warranty is for a year and as the company has a service location right here in the United States, you won't have to ship it back to China for service and if you have any questions, you can call them at (949) 336-4540. BTW, I have no connection to the company and bought my unit from Amazon on August 31, 2013.
Now for the all important question, how does it sound? In a word - amazing, it has a wide soundstage, is unfailingly rich and resolving with clean non-sibilant highs, a gorgeous midrange and deep, well controlled Bass (when it's present in the source material). That said, the one thing you must remember is that a player can only faithfully reproduce what was contained in the original source material, so great recordings sound great and mediocre recordings can sound no better than what was recorded. A good analogy is photography, if you take a picture that is out of focus, no matter what you do to sharpen it up it will always be hampered by what was missing from it originally. The AK120 is very revealing and so you will hear tiny details that you may have never heard before.
The AK120 was great with orchestral music, jazz, rock, and anything else I could throw at it. Even better sounding in some ways than my iPod Classic 160 (playing ALAC lossless) through a CypherLabs AlgoRhythm Solo/ALO RX MKII, Cowon Z2 with ALO RX MKII and my Galaxy S4 playing FLAC files through AlgoRhythm Solo/ALO RX MKII using USB Audio Recorder Pro 1.2.7 . Now to be fair, the AlgoRhythm Solo/ALO RX MKII are an excellent combination and sound great together but carrying three components strapped together is rather cumbersome and diminished my enthusiasm. Each has its advantages but I preferred the AK to the CLAS/RX MkII combo.
Female voices like jazz singers Diana Krall, Esperanza Spalding and Norah Jones sounded superb even in 16/44 FLAC with clear, extended highs, great microdynamics and a smooth detailed midrange. There was absolutely no glassy etch or harshness, even in the high notes Esperanza hits in her song "Fall In Love" and the stand-up bass she plays through most of the album is deep, dynamic and so distinct, you can even hear her fingers sliding over the strings. Well mastered recordings just sound great and this player reveals every nuance.
Male vocals sounded great too. Among those I listened to were Jose James, Kenny Rankin and the amazing George Benson. Every essential aspect of their vocal characters came through, from Jose James smooth baritone on "Do You Feel" to Rankin's clear, pure tenor showcased in "I've Just Seen A Face" on the album, "Here in My Heart" to the amazing range and character of George Benson on "This Masquerade" whose voice and guitar sound so dynamic and lifelike he sounds as if he is right there in the room with you.
Wind instruments sounded wonderful, from the astonishing tenor sax of Eric Alexander on David Hazeltine's "The Classic Trio Meets Eric Alexander" to the agile clarinet of tenor sax titan Joe Lovano on Steve Kuhn's "Mostly Coltrane" but it was with piano music on both of those albums that the AK120 really strutted its stuff. Piano is notoriously difficult to reproduce with authentic realism and yet when playing these two well mastered 16/44 FLAC albums, the virtuosity of both David Hazeltine and Steve Kuhn stand out with the piano always crisp and crystalline in the highs, tight and without echo or rumble in the bass with natural sustained decay all of it near perfect. You can even hear the dampers being activated when the "sustain" pedal is released, you are there!
As far as the headphone amps I used, I tired it with the ALO RxMkII but didn't see much improvement in SQ other than a slight increase in volume and in fact, I preferred the sound directly out of the AK120. I also tried a Headstage Arrow 4G and the JDS Objective2 Headphone Amp with similar results. The O2 was actually able to boost the volume more than the ALO Rx MkII and as it uses an alps potentiometer rather than the digital push button control that ALO uses (which raises the volume in stepped 3dB increments), it was easier to control the volume with the O2. That said, the O2 is a bit larger and therefore stays at home. For the money however, the O2 is a worthy amp to consider using with the AK and if you want to save a bit more, it is available in kit form. I initially bought the ALO amp for my JH-16 Pro and the two indeed have great synergy however, the AK120 sounds great with the JH-16's with no extra amplification needed at all and that is my out of the house set-up.
The amp I think pairs very well with both the AK120 and the HE-500 is the Lyr Headphone Amplifier which delivers a solid 4 watts per channel, enough to drive any can including the notoriously power hungry HiFiMan - HE-6 Headphones. BTW, a fantastic underrated tube for the Lyr is the Tungsram Hungary ECC85 which Schitt offers as a $50 upgrade for a matched pair instead of the GE 6BZ7 tubes. This is one of those tubes that you may enjoy so much you just won't want to switch to another to continue your tube rolling. Remember, you don't necessarily have to spend hundreds of dollars on rare, hard to find tubes to make your Lyr sound good!
I will repeat however that the AK120 sounded wonderful without any amplification when using most headphones and depending upon the amp, may actually be worse SQ-wise if you add one. The amp in the AK is very well designed and works well with the Wolfson DAC's, you could tell by listening to it that a lot of thought went into the design. It actually drives the HE-500 which in itself is quite a feat.