A Survey of Digital Audio Players Part 3 HiFiMAN HM901S


HiFiMAN HM901S ($1499)
I already covered the HiFiMAN HM-802 back in part 1 of this project. If you read that entry you'll be all caught up on the general info regarding HiFiMAN, so I'll try not to repeat myself. I'll mainly be pointing out the aspects which have changed from the earlier style represented by the 802.

The HM-901S is an evolution of their popular HM-901. This is a substantial refresh with an all new enclosure and extensive upgrades to the CPU and other behind the scenes bits. The actual DAC and output stage remain the same but those were already very highly regarded on the original model. So I don't see that as a problem.

Worth noting is the inclusion of a premium amp card right out of the box. HiFiMAN's modular amp design is great for variety, and the stock amp card, while fine with the HM-802, seemed to be a bottleneck on the higher end models. The old 901 sold for $999 but came with the stock card, while the 901S price jumps up by $500 but includes your choice of balanced card or premium "minibox gold" card. Each of these sells separately for $299, so realistically speaking the 901S commands a $200 premium over its predecessor.

External Design
Take the original 802/901 shell, keep the general look, but throw out the plastic and replace it with metal. That seems to be the direction given to the design team, and it largely works as far as I'm concerned. The feel is that of a more premium device, with only a small weight penalty being paid for the change. And since these are already chunky players, I figure their target market is not too worried about slim stature and light weight. I am always careful with my gear but I feel like the new metal frame could take quite a bit more abuse than the old plastic version.

Despite the improvement over the last generation, as I hold the 901S in one hand and the Questyle QP1R in the other, I can't help but feel HiFiMAN is outclassed. There's nothing inherently wrong with the 901S—it's an appreciable step up from the plastic of the 901, and the new rubber scroll wheel is especially welcome. Yet when I consider the fact that one of these devices is $899 and the other $1499...based on looks and build quality alone I think most people would peg the QP1R as being the more expensive of the two.

Internal Design
HiFiMAN won almost universal praise for the sound quality of their original 901. Even those who preferred a different sort of signature had to admit the 901 was an excellent example of a neutral, vividly detailed player. So it makes sense that they largely carried over the main guts of the original while tweaking the supporting hardware for an even better result.

Going back to that original model, HiFiMAN repeatedly pointed to their use of dual ES9018 Sabre chips in the DAC section. But they never seemed to specify whether that would be the original 8-channel ES9018S or the newer 2-channel ES9018K2M. I personally suspect the latter since it launched around the same time frame as the HM-901 and has a more compact form factor better suited for stuffing into a little device like this. ESS also markets the ES9018K2M as being specifically intended for mobile devices, with better power efficiency among other benefits. I suppose it doesn't matter as both chips appear in some very nice gear, and there's no proof either way without a full tear-down—something I probably shouldn't do with a review loaner. At least they are specific about the output stage which is built around a pair of TI OPA2107 opamps plus a set of OPA627s for low pass filtering and I/V conversion.

With the DAC and output stages remaining the same, HiFiMAN beefed up the power supply as well as upgraded the processor for better UI performance, which as quite welcome since the original was never known for its speed. It now more comfortably handles DSD compared to the 802 which sometimes stumbled due to CPU demands. PCM playback still tops out at 24/192 and all the usual file formats are supported.

I won't be discussing the headphone amp section much here since the modular system allows the use of several different amp cards. I'll just note that the included minibox gold card is substantially better than the old stock amp. That card was good enough when using the musical HM-802 but to make the most of the more resolving 901S, a better card is definitely worth it. The minibox gold is also significantly more powerful than the stock card for driving difficult headphones with authority.

User Interface
This is pretty much identical to the 802 with mildly improved responsiveness thanks to that new processor. It's evolved over time with firmware updates and looks somewhat more appealing than it did at launch, but the general experience is the same. The main thing worth discussing is the new rubber scroll wheel which is vastly improved over the ribbed plastic on the old design. Questyle should have learned from this and made their wheel with some type of texture as well, since it really helps the experience.

I have only two real complaints here. First, I do wish the wheel had some sort of speed-sensing algorithm so I could more quickly get to the bottom of a large album list. As it stands, spinning quickly or slowly doesn't make a difference—either way gets the same results. The Questyle actually works better in that aspect, so perhaps the ideal player uses elements of both designs.

My other complaint concerns the screen quality which is starting to feel pretty dated compared to the other contenders. It's still usable enough, though a higher resolution, more brightness, and better viewing angles would be very welcome.

Again, same thing as before for the most part. That means full-size SD card support—welcome, since a 256GB card currently sells for about half the price of a microSD version. It also means proprietary connection for charging, which I'd normally complain about except for the added functionality it brings here. An included adapter taps that port for line out and coaxial SPDIF data extraction—something not likely possible with a standard microUSB. So I see why they did what they did. The only real change to the 901S connectivity is the balanced output, which now gets a separate jack instead of an all-in-one with a selector switch like the prior model. I'm indifferent about this as I don't currently have any TRRS-terminated headphones to pair it with.


Let's talk about the optional Dock 1 ($499) for a moment. It takes a 901S (or a 901, or an 802 for that matter) and expands it to the point of being a true home component. The docked device can stand in for a CD player, playing internally stored music. Or use it as standard desktop DAC complete with USB, Toslink, and coaxial digital inputs. Either way, output to a headphone amp or preamp is easy thanks to standard RCA outputs, and there's even a "buffer" button which increases output voltage for better compatibility with certain gear. Or, use the docked 901S as a transport, feeding your external DAC of choice via optical or coaxial. Did I mention the handy remote control? There's a lot going on with this device.

The Dock 1 works as advertised in a home system. The only strange design choice I find is the requirement for separate power connections for dock and player. The dock uses a standard AC cable but also demands the charger from the 901S. The DAP can be used in the dock without its charger, but in that case it would run on battery...the dock can't power it or charge it without the additional power adapter being in the mix. Not a huge deal but it does involve messier cabling while taking up two AC receptacles. Aside from that, the 901S plus Dock 1 is a true high-end source component that feels (and sounds) right at home sitting next to my $2,500 CD player. I'll discuss it further in the Sound Quality section below.

The 901S goes for 9-10 hours just like the 802 did, and just like many competitors do. With its power supply plugged into the dock, I find it very convenient to just throw the 901S on there whenever I'm not actively using it. That way it's ready to go with a full charge at all times.

Sound Quality
The HM-901S is a highly detailed, resolving DAP with what I'd call a distinctly "HiFi" sound to it. By that I mean it has a very obviously sparkly treble, pristine midrange, and tight, clean low frequency extension. This is the type of sound which impresses right off the bat—it's almost jaw-droppingly clear in its presentation. It's also the sort of sound that makes me worry about listener fatigue over the long-term, but thankfully it holds up surprisingly well in that regard.

I started off with the IEM amp module which I had been using with the HM-802 prior. This card is not the most powerful thing in the word, to the point where HiFiMAN specifically warns against using it with anything other than IEMs. I don't necessarily agree, and find that it does a decent job with many easier to drive headphones. But I admit they are right in naming it the IEM card as it really does excel with my custom IEMs from Westone, Noble, JH Audio, Empire Ears, etc. While the 802 plus IEM card made for a warm, smooth combo with relaxed treble and a boosted low end, the 901S is far more neutral. The upper midrange and highs are not only more present but also more resolving and incisive. I won't go so far as to call it an "in your face" presentation though with some IEMs—specifically my JH13 FreqPhase and Unique Melody Merlin—it does lean in that direction.

I tend to prefer neutral to warmer IEMs with this configuration, which end up sounding extremely revealing and clean. The Jomo 6R, Empire Ears Spartan IV, Noble Savant, and RHA T20 all sound superb though somewhat unforgiving of poor recordings. If lifelike detail is your thing, any of these combos will do the trick. For the best all-purpose performance I end up reaching for the Noble K10, Empire Ears Zeus, or my favorite match, the NG Audio Capricorn. These allow me to enjoy mediocre modern recordings while still sounding fantastic with Bob Katz masterpieces. Yes, the IEM card is very satisfying to these ears.

Switching to the bundled Minibox Gold amp card changes things up a bit. The resulting sound is still plenty detailed and resolving, but now has a more organic feel to it. Transients are just a bit less well defined, which I don't feel is a particularly bad thing in this case, and drive is significantly increased over the IEM card. Even the analytical HD800 and overly-polite beyerdynamic T1 sound very respectable with the Minibox card in play. There's plenty of power too—it feels right at home with LCD-2, Alpha Dogs, HD650, HE-1000, and pretty much anything else I throw at it (within reason). Overall I'm quite pleased with the decision to bundle this card as opposed to the old stock amp.

The Dock 1 is a unique feature that sets HiFiMAN apart from the pack. While other brands to offer USB DAC functionality, including Astell & Kern with their attractive USB cradle, that feature is more oriented towards someone using a computer as source. To actually use the player as source in a bigger system, competing models are a bit awkward due to power and digital output cables protruding from various ports. In Contrast, the Dock 1 routes all cables through the rear, allowing the user to just drop in their 901S whenever they aren't using it on the go.

The HiFiMAN solution gives us multiple digital ins and outs for use as DAC or transport, plus a pair of single-ended analog outputs which sound mighty nice. I used the 901S/Dock 1 in my headphone rig where it replaced a $2,500 universal disc spinner and the playback quality did not drop by any appreciable measure. I also threw it in my speaker-based setup in place of a big 40 pound Calyx Femto DAC paired with an Aurender music server. While the resulting sound was a touch less detailed, it was also arguably more balanced and "complete"—certainly a different flavor but not at all outclassed by the far more expensive setup. I can actually see using this as my only source and being quite happy it in that role. There's a bundled remote which is mainly good for pausing or skipping tracks... still better than most others which have no remote at all. While viewing the 901S display from my listening chair isn't really possible, the whole experience is still very appealing overall.

In the end, the HiFiMAN 901S is surely an expensive DAP, and not without flaws. In some ways I feel it is overpriced considering the simplistic UI, mediocre battery life, and bulky construction. Yet in terms of sonic enjoyment and versatility, it's among the very best available.

tony's picture

This is one hell-of-a-summary!

Battery life, efficiency, Streaming, Quality, Design Integrity, you're hitting all the key points. What do I owe you for this? Buying the wrong feature Set is an expensive mistake.

Can you offer an opinion on the New Phones as Audio Players? the V20 for example.

It would seem that the World will be using their Phones as DAPs, I hope to encourage you to continue your "important" work in this new area.

Thank you for all this work!

Tony in Michigan

John Grandberg's picture

...are getting better (at least some of them). Unfortunately it seems like LG and others don't want to bother with us lowly audio journalists. I have a heck of a time getting replies from their PR people, which makes it tough to properly investigate. I'll keep at it though.

I'm currently using a ZTE Axon 7 as my daily driver and it's pretty impressive, both as a phone and in terms of audio quality. Not a true "DAP replacement" but very impressive for what it is.

flohmann's picture

A big omission, it seems to me, since the X1a is about $650, supports up to 400gb, and runs a newer version of Android than the Sony player (so runs all the apps that the Sony player does). Maybe Part 4?

John Grandberg's picture

I had the original DP-X1 when it first came out. Weird battery issues, and then the 3.5mm jack went sideways. I figured it was just an anomaly, but then a friend with a pretty decent measurement rig got some wild results with his DP-X1 - *extreme* deviation from the published specs. Those two experiences were enough to put me off when it comes to Onkyo.

Don't know if those issues are still present with the DP-X1a, and honestly I haven't kept up with it. But from now on I'll be doing updates one DAP at a time so I should manage to be more nimble going forward. Perhaps an Onkyo is in my future one of these days.

logscool's picture

I also had issues with my original DP-X1 and almost didn't get a second one after trying the not very good OPUS#1 I went ahead and got a second DP-X1 I've had no issues with the new unit. There is a pioneer unit coming out that looks to be identical (XDP-300R). There is also the single ended only version Pioneer makes (XDP-100R).

Meshail's picture

Why do you find the opus #1 bad or ( not good ) where is it lacking, I'm asking as I want to grab one now as price is like 290$ & you are the second person who is saying it is not good

logscool's picture

It just didn't have a lot of weight or dynamics to the sound pretty "digital" sounding in comparison to better sources. If you have a chance to try it then definitely try it as you might like it's signature.

Meshail's picture

Can you please suggest me a better dap in the sub 300 $ range as the opus#1 runs for 289$ on amazon

Long time listener's picture

I note you mention the Fiio X5, but they now also have an X7--disappointed not to see it as I would appreciate comparisons. I trust the Fiio brand, they use a good DAC chip, and the sound seems very good at the $600-700 range. But is there better?

Also, to Tyll, a review of the new Shure electrostatic IEM would be appreciated. Thanks

John Grandberg's picture
See, there's the dilemma I mentioned - always another worthy model coming out. I finally had to put my foot down and just go with what I had, else it all became irrelevant. But I definitely intend to catch up on newer models from Fiio, Cayin, Astell&Kern, and perhaps the new Sony models. One at a time though!
thefitz's picture

I use the DX90 because you can plug in a USB hard drive via OTG. Use Western Digital drives. 2TB+ at my fingertips!

John Grandberg's picture
The literature for the Acoustic Research M2 also mentions the same OTG functionality. I never actually tried it but I can see how that might come in handy in some cases. Thanks for the info!
jcheadphone's picture

Thanks John. Really enjoyed reading your three part series on DAPs. I used to own the Calyx M and agree it sounded wonderful. I ended up selling it because of the shortcomings that your mentioned and others. I currently own a ZX2. It sounds great and is able to drive all my headphones from my Shure SE846 to Audeze LCD-XCs with good results (although the XCs as expected certainly benefit from a desktop headphone amp). I also picked up a pair of Sony MDR-1000x wireless noise cancelling headphones for travel. The LDAC streaming with the ZX2 sounds very good. In A/B tests with 16/44 ALAC and FLAC tracks I can't distinguish a difference between the wired connection and the LDAC wireless streaming. I note that Sony has now made LDAC available on the licensing market so maybe we'll see it on other non Sony Bluetooth products in the future.

Three Toes of Fury's picture

As a big fan of better quality sound on-the-go, the ever evolving DAP market is of big interest to me. I very much appreciate you taking the time to review so many entries. Its great to see this site evolve in its review and wall-o-fame offerings.

Great stuff...keep it up...even if you dont do the huge comparison reviews (takes loads o time im sure), drop in with a 1-off review of a DAP every now and then. Would be much appreciated

Peace .n. Living in Stereo


GlennT's picture

I own a Questyle QP1R and I love it. However, I agree that the scroll wheel's functionality is disappointing. Before I bought the QP1R I had the expectation that the scroll wheel on it would be as useful as the old iPod scroll wheels used to be, but that's not the case. I find that the touch-sensitive buttons around the outside of the scroll wheel as well as the button in the center of the wheel become usability obstacles when scrolling. It's too easy to accidentally brush against the touch-sensitive buttons when scrolling. It can be very frustrating when trying to scroll to a specific selection only to suddenly be dumped back at the home screen because your finger accidentally brushed against one of the touch-sensitive buttons surrounding the scroll wheel. The wheel is also pretty slippery, making it sometimes difficult to grip. However, they have an adhesive film that goes over the scroll wheel that Questyle will provide to you upon request at no cost that mostly solves this problem.

husafreak's picture

I am a huge fan of my QP1R. It is beautiful and sounds fantastic. Clean, dynamic, and detailed. Your review is on the money. I would say that the scroll wheel cover is a must to facilitate its use. I believe the unit ships with them now but they are free and easy to get, actually something as simple as a generic stick on rubber dot can solve this design flaw.
I use mine with a set of 64 Audio U6's, TH-X00's, and now Mr Speakers Ether Flows. It is amazing to me how much detail and life I can hear with the Ether Flows. I had to comment because my son is a drummer, a professional now, and so I really get into the nuances of drums and cymbals. I swear I could hear the double bass chain mechanism rattling away when I was auditioning the Flows through my QP1R! I look forward to hearing the Spark album you used in your review.
By the way there is a very active QP1R thread on the Head-Fi forums and the company has been very proactive in releasing timely updates. In only one year they have solved many requests.

John Grandberg's picture
...for the comment. Glad you are enjoying the QP1R. The firmware aspect is yet another category which I probably could have used to judge each model, or at least each brand. Questyle is indeed one of the better ones in terms of frequent updates.
Jayhawklaw's picture

I love comparisons like this. I hope you (and your sister publications) do more. So much more meaningful data for the "everyman." I would love to see a similar survey for portable dac/amps (e.g.: Audioquest Dragon Flies Red and Black, Oppo HA-2SE, Chord Mojo, etc.)and how a smartphone with one of said dac/amps connect compares to the dedicated DAPs.

jcheadphone's picture

At first I was disappointed that Sony decided to go with a proprietary WM port rather than micro USB. When I contacted Sony tech support via phone to ask about this the tech rep said the WM port was intentional because it allowed the left and right channels to be separated for optimum line out sound quality. Don't know how much this explanation holds water but thought I would mention it.

John Grandberg's picture
They say the same thing about their 3.5mm jack. Not sure it really makes a notable improvement of any sort in terms of SQ, but it's a perfect example of Sony being Sony.
Martin.'s picture

The only DAP that seems "consumer friendly" in my eyes is the Sony NWZ-A17, which is priced at 300$. Is it even worth buying a DAP for 300 usd when you can save a bit more for a mojo at ca 500? The real question being, other than portability, what advantage would a 800$+ DAP have over a 500$ portable DAC like the mojo and, most importantly, would it make a discernible, audible difference? Thanks for any answer :)

John Grandberg's picture

Different folks will have different priorities, and each solution has pros and cons.

I like a dedicated DAP because it's smaller and easier to manage than a phone-plus-Mojo type solution. Also many phones don't have expandable storage so a DAP with 128GB or 200GB (or more) can be useful if your phone is stuck at 32GB or even 16GB. If we're talking Sony ZX2, then battery life is supremely better than a Mojo. Last but not least, there are various sound signatures to be had with different DAP models. Not everyone loves the Mojo presentation, as popular as it seems to be. The target market who prefers the sound of a Cowon Plenue 1, for example, is not likely to be thrilled with the Chord.

On the other side, it could be argued that you always carry your phone with you anyway, so a DAP isn't really saving any space over a Mojo setup. And a decent phone is usually superior when it comes to display quality, ability to run apps, etc. In some (many?) cases the Mojo sound will be superior depending on your criteria.

I agree that there aren't enough affordable options right now. I'm still looking for a true replacement for the Sansa Clip/Clip+/Clip Zip. Only reason I can't put those on the Wall of Fame is the fact that they are long since discontinued.

Martin.'s picture

Thanks for your answer. Being a novice, I usually want a "this is best" answer because I feel I need to be told what is best by veterans in the field. It is nice to be reminded that audiogear is personal and that "different strokes for different folks". Your well balanced answer is much appreciated.

br777's picture

has convinced me yet to give up my sansa clip zip.

Rblnr's picture

Very comprehensive and useful reviews. I've been using the Plenue 1 for a couple of years after testing it against others at the time of purchase and am still very happy with it driving JH Audio Angies and some over the ear headphones as well. Surprised that Cowon doesn't get more attention. The sound is as described, smooth and easy, but by no means lacking dynamics micro or macro. Sometimes I want a more 'in your face' sound and the BBE and other profiles ( as noted in the review) can provide that to a point.

I also have to say that I have little tolerance for wonky interfaces anymore -- time for those manufacturers to enter the 21st century, whether or not interface is really their expertise. The Cowon's ergonomics, while perhaps 'merely' utilitarian, are at least direct and unfussy.

Peragulator's picture

No love here for the X7 I see.

John Grandberg's picture
I just had to stop accepting or seeking out new models at some point, or else I'd never get this thing finished. I intend to revisit different models from time to time, so a Fiio of some sort is certainly on the horizon.
Trebor74's picture

Hi, great review! Are there, or will there be, any measurements available at some point to complement the reviews? I'm especially interested in the Cowon measurements - Cowon and a couple of other sites have posted THD figures for the player but these are probably not with any load. I'm curious to see how well it performs (in terms of THD both in earphone and headphone modes) on some low impedance cans. Thank you!

Peragulator's picture

AK300 ($899.00) Sony 1a ($1,199.00) FiiO X5 3rd gen ($400.00) Pioneer 300r OPUS #2 ($1,400.00)

yc627's picture

I'd Love to see some flagship phones' real world comparison in their ability to reproduce sound through headphones... Such as:

Sony Xperia XZ premium: they say it can do 24bit 192kHz audio. And Sony's own LDAC bluetooth codec. How does it sound like with Sony h.ear go SRS‑HG1 bluetooth speaker compared to other devices... + Sony Xperia Z series and to the XZ lineup, they had this noise cancelling earphones that needs no battery boxes like the Sony MDR-NC750 and MDR-NC31E I also wonder what you guys think about those earphones.

Samsung Galaxy S8: I hear it can do 32-bit/384kHz audio and I wonder what audiophile people would think about that.

LG V10, V20, V30: I heard they got 32-bit/192kHz audio and B&O Play certified. LG seems like they don't really do a lot of marketing on the audio parts what do you think about the B&O Play certification?

Just a question from a college student who is somewhat regretting getting a Sennheiser Momentum 2.0 just because it had a huge discount on Amazon and is thinking that I should have gotten the V-Moda M100 or Sony H.ear on MDR100ABN or just go crazy and go with Sennheiser Momentum Wireless...

trl's picture

Based on https://reviewzorro.com/wp-content/uploads/2017/08/HifimanHM901s3.jpg seems that Hifiman 901S has 2 x ES9018S inside. Quite impressive, so that explains the price indeed.