Some DAP comparisons
The HM-901 is far more resolving and slightly more neutral sounding than the FiiO X5. It also comes across as less digital and more natural sounding especially with the balanced card. The FiiO X5 is a heck of a lot cheaper than the HM-901, possessing a longer battery life and a UI that is probably a bit more engaging in terms of what you can do with it compared to the more limited and utilitarian Taichi UI of the HM-901. For those on a tighter budget the FiiO X5 is an excellent choice but the higher resolution combined with the flexibility of the amp cards and better dynamics put the HM-901 on another level.
The AK100, the original AK launch unit, has the form factor, longer battery life and dual microsd slots with more onboard memory than the HM-901 and also possesses a nice touch screen UI that is easy to work with but I normally end up pairing the AK100 with my Vorzuge DuoAmp given its rather lackluster performance with IEM’s and a high impedance output. The HM-901 made the AK100 sound extremely digital and cold for me and it didn’t have the same levels of power as the HM-901 especially when used with the balanced card.
I suspect the real battlefield for the HM-901 is with the AK120 and even the AK100 MK2 but sadly I do not have either to test – sorry chaps. I do know though that those who have tested the HM-901 against the AK120 have been rather split down the middle with some preferring to go with the AK120 on a wide range of factors such as the touch screen, battery life, memory capacity, and the dual Wolfson WM8740 DAC tonality and others preferring the power of the HM-901 and the versatility/tonality of the amp card system. Also the very interesting dual Sabre DAC powered Ibasso DX90 is due here in a few weeks so I will add some notes to that review on how it compares to the HM-901. It’s selling for $419 also which could be a very tempting price point for many.
Given the HM-901’s relatively neutral tonality, high levels of transparency and lush fuller sound on the balanced card it was no surprise to find it matched well with a number of harder to drive and headphones even in unbalanced mode. Planers such as the Alpha Dogs by My Speakers drove really easily on the HM-901 at around 5-6 on the pot and combined with the excellent imaging and micro-detail of the Dogs and the dynamics of the HM-901 on balanced made this a very engaging match. The relative transparency and neutrality of the HM-901 didn’t color the tonality of the Alpha Dogs thankfully. I know a few are critical of the treble performance of the Alpha Dogs compared to the Mad Dog and Paradox versions which roll off the treble a bit more but that weighted and coherent bass and crystal clear mids are superb on the HM-901 and a pure winner for me.
Continuing with the planer theme I slipped on the LCD-2 in unbalanced mode and once again volume wise there were no issues with the LCD-2 which was happy to run at exactly the same level as the Alpha Dogs volume wise and sounded really alive with a visceral and tight bottom end that really kicked hard and plenty of bass extension and detail. I won’t go into too much more detail for the new Oppo PM-1 planer as I have a full review of that coming out but bring rated as the most efficient and sensitive planer in the market the HM-901 had zero issues running the PM-1 which displays a thicker more closed in sound that works very well indeed modern pop and rock genres. Imagine the HD650 a few notches higher in resolution and without that veil and you are not far off the Oppo PM-1 matched with the HM-901 balanced amp card.
Perhaps the biggest surprise for me was the HE6 and the HM-901. I am usually quite skeptical when it comes to anything other than Class A min of 5 watts per channel and preferably balanced and true enough the HM-901 doesn’t drive as authoratively as the Mjolnir or the EF6 but what it did seem to manage to do was to give me a competent level of volume control between 7 and 8 without clipping or sounding overly thin or tinny and definitely not sharp. Outside of the DX100 I think on experience this is probably the only DAP I could recommend at this price point to pair with the HE6 and even then I much prefer the more natural tonality the HM-901 with the balanced amp card over the DX100.
For more portable headphones I actually preferred using the Minibox amp card over the balanced card. For example my ATH-ESW11 Limited Edition just felt too forced and claustrophobic with the balanced card as well as having to massively reduce the volume (3-4). Stepping ‘down’ on the power and widening up the frequency was a lot more relaxing and allowed the ESW11LTD to produce a greater sense of space and control. The Senn Momentum, although at similar reduced volume levels, performed somewhat better than the ESW11LTD sounding slightly less claustrophobic though ending up a bit more sibilant than I would have liked on some vocals with the Minibox amp card.
Click on next page for final thoughts & technical specifications…