The impression below are based on Firmware 1.2, it’s the latest up to date
The Astell&Kern AK70 is on the warmer smoother side of sound but at the same time it shows good detail and clarity. Of course it isn’t at the same level of the AK380 but it’s still pretty good. The AK70’s sound stage wide and depth is good and very correct at the price it is going for but you don’t get the layering and spaciousness of the higher end models.
I’ve both used the single ended and balanced output equally and depending on the monitor/IEM in use I prefer the balanced or SE output. I hate to repeat myself but the 2.5mm out has a more expansive sound, with a little less bass and body but with more air and separation. The AK70 always has a black background and it is completely silent even with my most hiss sensitive custom monitors. The volume control for that matter is dead silent and there is no channel imbalance in any way with the gear used in this test.
The AK70’s bass and mids have good body (more than neutral) and the treble section is soft and smooth and won’t ever sound harsh or sharp in any way. The AK70 sounds musical, full bodied and detailed but I couldn’t say it’s neutrally tuned. The AK70 has a rich sound where the level of detail isn’t as noticeable as with the AK380, DX90 Lurker or even the X7 for that matter but it doesn’t disturb in any way. What might disturb some of you is that the AK70 isn’t the fastest sounding DAP, its attack and pace is moderate. Another thing some might not like is the fact that the AK70 doesn’t do perfect gapless playback, something a whole lot of the latest DAPs – not just by AK – suffer from.
I’m not an avid user of Bluetooth but the new Beyerdynamic Byron BT performs extremely well over aptX Bluetooth connected to the AK70. I feel Bluetooth isn’t far away anymore from replacing cables completely while offering the same sound quality. I do like my cables though as they allow fine-tuning the sound, I don’t see us doing that over BT.
Data Source (OTG) & DAC & Line-Out
Besides being a wonderful DAP, the AK70 can also be used as a DAC for your laptop or any other compatible media source. At the same time it can also be used as a media source connected to an external USB. That does mean you can connect the AK380 to the AK70 and have either of them work as DAC or Source. While it shouldn’t matter I can only confirm what Alex An posted on his Facebook page: the AK380 with the AK70 serving as source sounds extremely good. I’ve even seen people buy two AK70’s to run them as DAC and source separately.
That of course is an extreme thing to do and most people who want more power or a different sound from the AK70 will be pairing the AK70 to an external AMP/DAC. The only thing you need to have to do that, besides owning both units of course, is a good OTG cable. I’ve got a bunch of short OTG cables I got on Ebay but ever since I saw Alex An and others using the red ASEN Avanzato X-limit OTG 0.1 I just had to get one. The guys from Asen don’t normally ship to Europe but they were so nice to go through all the extra trouble and send a pair for me and my friend. This cable has the perfect length and it’s very well built. ASEN isn’t very well known yet in Europe or the USA but they’re big in Asia. I do recommend you check out their affordable products, I love the red cables.
Its size is an advantage the AK70 has as it fits perfectly when stacked to the C5D or the Mojo as you can see in the pictures. If you look for Mojo or AK70 pictures on the www and head-fi, you’ll quickly see these two devices get paired all the time. Do note that for the C5D you need an OTG USB mini to USB micro cable. Connected to the Mojo you’ll get a clearer sound with more detail and precision. Mojo sounds more neutral and so you’ll miss the full bodied bass and mids you get straight from the AK70. Which one sounds best depends on the headphones/earphones in use and the mood I’m in. Connected to CypherLabs’ Picollo DAC, you get a slightly warmer sound with deep and layered bass. Vocals are slightly more upfront and you get livelier treble than from the AK, they also stack perfectly btw. I have connected both my AKs to each other and I have to admit it sounds good but don’t go buying AK70s to serve as data carrier for your AK380, that’s just crazy (but crazy doesn’t hurt).
Of course you can still use the Line-Out from the AK70 to bypass the internal amp section and feed it in to the (portable) amplifier of your choice. When I feel like listening to a more tube sound, I hook it up to the ALO Audio Continental V5 (the new amp) which adds richness, has better layering and sounds more spacious. When I want more qualitative bass and mids with livelier treble I bring out the CL Picollo and the Meier audio Quickstep gets airtime when I want a more neutral and detailed/precise sound.
Fiio’s X7 is a little more expensive at €699 (in Europe) and $599 in the US. The X7 is very different from the AK70 as it has different amplifier modules making it more versatile and more powerful. TheX7’s Android operating system also allows more fine-tuning. The X7 is a lot heavier and bigger than the AK70. Sound wise the X7 has the advantage that you can change the amplifier module but overall I would say the X7DAC is more transparent, it gives the impression to show more detail in a cleaner way but. The X7 to me is the more precise and detailed one and the SQ maybe is a level up. On a day-to-day basis though, I prefer using the AK70 over the X7 when on the go.
Cayin’s i5 DAP was released about a month ago but we’re all waiting for the latest firmware to be released (with the USB DAC function activated) to do the final review on it. The €499/$469 i5 is very much like the X7 when looking at the firmware and user interface. Of course it doesn’t have all the different amplifier modules like the X7 does but that also means it doesn’t have a balanced output. The i5 has the typical full bodied sound and I have to say I’m a big fan. I do find the i5 to sound richer and more detailed than the AK70 and it also has better layering. Sound wise the i5 is sublime and if it was a little smaller, was less noisy with sensitive gear and had a balanced output it could just be the best DAP in this price class. The i5, or the AK70 for that matter, both don’t have the finesse and refinement the TOTL DAPs like the AK380 have.
More comparisons and the part on headphones/earphones can be found on Page 3, right after the CLICK