Disclaimer: I purchased the unit in this article from e-Earphone in Akihabara. The AK70 goes for around 600$ USD. You can find out all about it here: Music Friend In My Pocket, AK70.
Subject: Astell&Kern AK70
Marketing copy worthy of blooper reels is one of Astell&Kern’s fortes. And, Music Friend In My Pocket, AK70, is the cringingly, suggestively ugly even by AK standards. Bravo. Despite, this, the AK70 itself is handsome. Sure, its Korean edges will draw blood. But it is shorter than an iPhone 5 and not much larger than an original AK120. Get a case for it. It will fit in your pocket.
It wears light metallic aquamarine like a boss, and has a much nicer, unlaggy screen and interface than previous mid-tier Astell&Kern’s players.
And while I’m not ready to commit hardened opinions about its sound on this page, I am confident in saying the following: the AK70 outputs minuscule levels of signal noise, and in most cases, kicks out grippy, detailed signals. Hiss is barely audible through either its balanced or single-ended outputs. And with a 2,3 Vrms output, it gets about as loud as an AK380. Under load, the two return chummy results. Both reject hard non-pattern artefacts at volume levels above 130, but under the load of earphones like Jupiter, Nova, and even the Earsonics SM2, return inordinate THD, IMD, noise artefacts. Unloaded, you could argue that the AK70’s single-ended signal is cleaner, though the 1dB of difference between the two is practically outlier. Considering that the AK70 is 6x less precious than the AK380, it should be recognised as the sweet spot of Astell&Kern’s DAP lineup. That said, its balanced output, like the AK380’s balanced output, is rife with distortion and non-pattern artefacts. It leaves a lot to be desired (16.000x more THD). Still, it is a bankable feature.
And, despite the price disparity between the two, the AK70 manages all the physical accoutrements of AK’s high-end players. If, like me, you prefer milled iconography to paint-it-and-forget-it decoration, it kills it.
Note: the Earsonics SM2 typically used in measuring parallel signals from the AK380, Opus#1, Mojo Kai, etc., lost its balanced cable. I’m left with a balanced MMCX, which I paired with the Campfire Audio Jupiter. As soon as I can find a replacement, I will update this article with SM2 results.
Source: Astell&Kern AK70
ADC: Lynx Studio HILO LT-TB
Computer: MacBook Pro 21015; 2012 27" iMac
Cables: 1,5m Hosa Pro 3,5mm stereo to dual 3-pin XLR (around 8$)
Loads: measured at +0dB @volume levels equivalent to iPhone 6 max output (136/150)
NL - no load
Jupiter - Campfire Audio Jupiter (ohm image: Eyes on Jupiter; headfonia: Jupiter pre-production report)
ES7 - Audio Technica ES7
DT880 - Beyerdynamic DT880
24-bit single ended (SE) TARGETS and loads (@VOL 136/150 +0dB)
24-bit balanced (BAL) TARGETS and loads (@VOL 149/150 +0dB)
24-bit balanced (BAL) NL and Jupiter (@VOL 136/150 +0dB)
End words
While I’m partial to the AK Jr’s warmth, it exhibits little of the care with which AK developed the rest of the series. The AK70, on the other hand, brilliantly conserves the series’s high-end image, and objectively, packs a real whammy of a feature set. It looks great, but like all modern AK players, without a case, handles like a bear trap. I’m excited to see what Lieven has to say about it next week.