March 22, 2015

I am usually a bit hesitant at any literary toe dipping into the cult of personality, especially when it comes to audio gadgets given the rate of tech R&D share out there but in this instance I could be persuaded to change my mind given the pedigree of a certain Jason Wei-Min Lim. Cue the Troy McClure jokes but you may have heard of him in such previous classics as Ex-CEO of NuForce (yup who has not had the uDAC at one time in their life or another) and current brains behind Heap Venture PTE Ltd whose brands include NuPrime Audio and Celsus Sound.

Unlike dear old Troy though Jason very much isn’t in retirement mode, at least not yet and with the Celsus brand he might just be onto something pretty cool that could well be ahead of the competitive curve. For his sake I hope not too soon but in any event the all new Celsus Companion One DAC is one heck of a Swiss army knife of hi-res listening options. Hi-res streaming, heck even the word hi-res, is trending heavily right now in audiophile circles and has the mainstream gadget merchants chattering on its plus and negative points. Just recently the New York Post waded into the Pono/hi-res debate with a decidedly chilly overview on the benefits of lossless to the average Joe blaming it all on the illogical OCD lust of wallet emptying audiophiles needs for perfection without any sort of grip on reality. Each to our own dream I say and after a few solid weeks with the Companion One I would take a solid $50 bet to the New York Post along with a few earphones and just say “try it!”.

What is most striking about the Companion One is that it pretty much captures just about 99% of our current listening styles in one achingly modern looking device. I am not just talking about USB and perhaps OTG and lightening compatibility and a healthy dose of lossless codecs. That has been done to death by some great units for the past few years. It is the addition of a built-in wifi network and in particular wifi streaming in hi-res mode is what makes the Companion One a very interesting device indeed, particularly if you just took out a subscription to say Spotify or one of the hi-res streaming sites that are now cropping up all over the place.
I did say achingly modern looking right? Just catch a look at that case alone in the picture below. Celsus designed this modern audio slab as an ‘on the go’ package.

The leather carry case is probably light years ahead of most “me too” satin or velvet draw string pouches you get these days masquerading as high end carry cases. The split inside is just perfect housing for a regular size 4-5″ phone (boo I have the Z Ultra) and the Companion One (2 slots). It really does scream “we thought of who might like this and we know how you want it to look”. Just for giggles I put the Oppo HA-2 in slot number 2 beside the Companion One. It felt manly, stylish, like an executive listening pack of connectivity devices. If this doesn’t find its way into an Apple Store at some point then I do not know what qualifies as stylish anymore.

The rest of the Companion One connectivity package is a simple set of white cables, much like the Aurender Flow, for connecting to the wired device of your choice and for charging the Companion One itself. One for OTG, one for Lightening iOS, a 30 pin connector for those who resisted the ‘upgraditus’ over the last few years and a USB A to USB Micro B charging cable/DAC cable for PC/Mac’s. Sadly no SPDIF or optical cable in sight which would have completed the line up in terms of all round wired connectivity. Otherwise it is a neat and tidy accessories kit with the emphasis on the unit and the ‘spiffing’ leather case with a spare screen protector and microfiber cleaning cloth.

The One is Many

No kidding this is one myriad of features housed in a very minimalist modern design. From afar you could be forgiven for thinking it is a rather thick Smartphone or iPhone given the familiar lines and curves. Close up it much bulkier than the iPhone but those lines give it a familiar feeling in your hand. You almost expect the top black screen to light up with some sort of information but it doesn’t. Instead the only digital interaction you get is at the top and bottom of that ubiquitous black panel with a 4 LED light battery indicator (bottom) and the LED mode wave form light (top) to indicate USB or Wifi. You will not be receiving any unwanted in-law’s “Face Time” calls on this device instead all you get is the Celsus One logo, albeit a classy looking logo.

The build quality is top notch though and finger friendly. One caveat is that the top panel, gorilla glass toughened and stylish as it maybe, does not have any etched labeling apart from hints on the out of the box plastic peel off cover. Take that off without familiarizing yourself with what output and input does what and you could be using that PDF manual more than you bargained for. There are no physical buttons at the top either, it is all on the sides alongside some strategically place air vents.

The physical button and input/output control on the side is a mix of the familiar and the new. To the rear you have two different micro USB inputs. The first is a universal micro USB input for charging the Companion One and the second, to the right, is a recessed micro USB for source input. To the front you have an SPDIF 3.5mm output and a 3.5mm analog headphone jack output. To the left you have a digital +/- 100 step volume control and on the opposite side you have a USB/Wifi toggle, gain and the wifi network control buttons. It is this side that will give you most cause for a careful read of the manual.

Battery Life

You can charge the Companion One via USB via your computer or any DC 5V/1250mA compatible AC and you can gauge its charge levels at any time with the 4 LED blue lights at the base of the black gorilla glass top plate. The LED lights will go into ascending blink mode 1 to 4 during the charge cycle and when charging is complete it will stop blinking and remain steady blue. The more battery you use up the lower the LED light count. Each LED accounts for roughly around 25% on the battery. Kind of like how the Cayin C5 amplifier LED system works (though they do 3 instead of 4).

When the battery hits a low point the top LED “wave form” light will go from either blue or green (wifi or USB) to red. There is no degradation of the sound on low battery it simply shuts down. Battery life is projected to play around 10 hours on average with a 6000 mAh battery packed inside but this may vary slightly depending on how you use it. You will get longer cycles on wired than wireless naturally and increased gain or output demands will lower by 1-2 hours roughly. Thankfully for those like me who nod off during charge cycles the Companion One will shut down 3 seconds after a full charge to prevent it being over charged. Just as well as it takes a whopping 8 hours for a full charge meaning basically an overnighter.


This is where the Companion One puts it’s marker down. Not only can you go wired to both computer and mobile platform, which is a rarity in its own right, but you can also take it wireless and to a very high standard in resolution indeed.

The Companion One is much like the Aurender Flow in this respect and also shares some similarities to the Creative E5 in terms of its wired functionality. You can connect the One to a PC, a MAC and also via OTG to an Android device as well as any iOS device of the last few gens via the lightning cable supplied. That pretty much covers 99% of mobile and desktop users right there as mentioned before. Connectivity to Windows though is through a set of proprietary drivers which you need to download from the support section of the Celsus website and it is plug and play for MAC’s. The Companion One has 2 USB audio transfer modes; FS and HS. Both denote speeds of transfer with the FS clocked at 12mbps (full speed) and HS chiming in at 480mbps (high speed). Pressing the Connect Mode button for two seconds toggles between FS and HS modes.

Note the Companion One uses ASIO and not WASAPI drivers. If you rely on WASAPI you will find some bugs in the One playback when using with Foobar. You can start play, but if you stop or pause and try to restart you will get an “unknown error” or “component in use” type error and even restarting Foobar will not work. Better to install ‘ASIO for all’ for Foobar also and work from there as it presents a largely bug free experience on all platforms including Foobar.
The One supports up to PCM32Bit/384KHz, DSD64 and DSD128 decoding and USB hi-speed and full speed mode when connected to a PC or MAC. Just to note that DSD decoding is also native decoding which was once the preserve of high end systems just a matter of months ago. Such is the speed of DAC development and implementation the adoption of high end DSD decoding is fast becoming the norm rather than the exception.

The One also supports Android version 4.2 and iOS (iPhone 4/4s, iPhone 5/5c/5s, iPhone6/6 Plus, iPad/iPad2/iPad Air/iPad MINI) devices. For Android it is simply plug and play for those with Digital Audio out via OTG like most of the new gen Sony and Samsung or OTG via apps such as USB Audio Recorder Pro (higher bit rate also) for older gens and those wishing to bypass the usual 16bit resolution limit from digital out direct on stock apps. For iOS its simply plug and play but again its limited to 44k 16bit in much the same vein as Android.


The icing on the cake and very much a modern trend given the endless lists of streaming sites and NAS/network setups in consumer homes that can broadcast in both hi-res and other tasty formats. The One uses a 2.4G wireless network and supports DLNA, Airplay and Qplay giving it plenty of flexibility in both the PC and Mac domain. The One also supports all commonly available music file formats, including FLAC and WAV. Though it loses DSD native playback at DSD64 and DSD128 over wireless it still decodes to a very respectable PCM 24 Bit/192KHz rate over wifi. That gives it a clear edge over do it all convergence units such as the Creative E5 which is wireless through aptX BT only and the newer Oppo HA-2 which has no wireless whatsoever.

Using the connect mode button on the side of the Companion One you can elect to connect via AP mode one-to-one using Companion One Wifi SSID) or Client mode (using an existing Wifi network). If there is no connection available in Client mode the Companion One will default to AP mode. Personally I was happy enough to try it over the AP mode and everything worked but note, this is not kids play in setting it up. It will require a level of careful reading again of the manual if you are not network savvy. My own particular experiences was a bit hit and miss in setting it up initially on my Sony Ultra Z using DLNA Throw but once you get the hang of it things go more smoothly. Those with existing home networks should find the task of connecting the Companion One a little bit easier especially if you are already using Airplay technology from Apple.


The Companion One’s internals are a ES9018K2M DAC which is the same DAC used by Ibasso in their dual Sabre DX90 and the rather impressive The Resonessence Labs Concero HP. It even pops up in the Meizu MX4 though sadly the MX4 is also saddled with “Retina Sound”, quite possibly the worst meme in the history of bad audiophile memes I have heard to date and does the Sabre DAC no favors at all. The ES9018K2M DAC, if well implemented, punches way above its weight, relatively cheaper to source and uses less power than its bigger and more illustrious sibling the ES9018 making it ideal for the Companion One’s on the go profile.

The Companion One’s amping is delivered via a mixed set of opamps including the OPA1612 for analog delivery and conversion and a AD8397 for buffering and output gain. Both combine to produce a very impressive level of sensitivity and output gain control. The One can handle loads up to 300ohms making it an amp that is ideally suited to working with a wide range of gear but not exactly a power demon in the same mold as the all conquering HPA-01M from Bakoon or even the Cayin C5’s amp but it certainly is far more adept at working with IEM’s and low impedance cans like Grados. The amp has two gain modes controlled by the Gain button to the side of the Companion One. You can toggle between both gain modes by pressing and holding the gain button for 2 seconds. Low gain is ideal for IEM users and the One starts in low gain by default when turned on at 1.5Vrms output (0db). Switching to high gain will work better for more demanding headphones (read above 32ohms) at 3Vrms stretching up to some of the latest gen planars also though by no means class leading.

Sound Impressions

Tonally the Companion One is relatively neutral and very natural sounding with a response that I found to be much more musical than analytical.

Bass weight and definition is a strong point but in a more composed and articulate manner than all out slamming bass head style. There is a nice fullness to its sound with good detail and extension but staying decidedly coherent rather than overpowering. It brings just the right amount of weight to the table without being accused of being overly colored or too heavy. The fuller sounding low to mid range keeps that musical signature ticking along nicely whilst the relatively short decay stops everything from getting muddy or boomy when pushed.

The mid range continues in the same vein being relatively smooth and open with a very nice sense of control. Vocal presence is clear and grain free and lacking in any harshness or brittle tones. Running the One through quite a lot of challenging female vocals tracks and sibilance control was admirable indeed. I couldn’t get Diana Krall to pillow talk me once with a single “ssss”. The Companion One took a sensible approach to treble performance aiming for a balance between smoothed out long term listening and articulation and clarity. It’s got enough detail and articulation to make it a very flexible ‘companion’ to most modern pop, rock and indie genres with the right match. I wouldn’t go as far as to say it is a laid back smooth treble but it wasn’t terribly invasive, tizzy or unnatural. Glad to say no noticeable ‘Sabre glare”.

Wireless Performance


When switching to wireless playback there is a tiny bit of lag using Sony DLNA on my Sony Z Ultra and their ‘Throw’ connectivity. Not by much though, we are talking less than a second which is highly commendable (AP mode direct wifi connection used rather than Client mode). I must warn you that it tends to gum up the Walkman app a bit if you are bit control happy. I suggest to connect with the Companion One first, breathe for a few seconds, then play your song of choice or else you could be caught in an endless loading loop forcing you to have to exit and reconnect to the One. Of course I could be a complete IT noob here with a phone that simply doesn’t like the Companion One and yes it is rather all new to me but the success of something like the One should really be in the ease of use for one of its major features. DLNA on Android right now comes up a bit short to really sell the One to the masses.


Using the One in AP mode with the iPad via Airplay was much easier to set up compared to DLNA but with a tiny bit more lag (talking nano seconds difference) than using DLNA. Rapid control on the playback of the iPad was a bit hit and miss in terms of getting an instant response but nothing like the hanging like the Sony DLNA setup. Volume can lag a little when moving it up and down so be careful to move it cautiously to the level you think you will be comfortable rather than go up until it responds because trust me you will go a bit further than you like (yup been there, done that, bought the t shirt). Otherwise its really plain sailing from there and much more enjoyable experience on iOS for casual pick and go use.

When everything works on both DLNA and Airplay it sounds head and shoulders above anything aptX or Kleer can provide with a far more expansive and detailed performance than the Creative E5 can produce. It still retains that natural free flowing sound, possibly a little smoother but very listenable and non fatiguing. Definitely a much more credible reproduction than wired mass market OTG stalwarts such as the cheaper D Zero MK2 from the Ibasso and the FiiO E18 or the BT aptX enabled Creative E5 .



The Companion One is rated to work with both IEM’s and cans up to 300ohms however it also has no issues with some planars that I hadn’t really expected it to push with any conviction such as the Alpha Primes and the HE400i. The Primes in particular, via Foobar out of the Companion One headphone jack, came across as clear and responsive with only a slight diminution to its famed dynamics and imaging when driven with something more powerful. The Primes still responded quite well to all the EQ tweaks I like playing with on the Primes especially on the 55HZ setting giving a satisfyingly deep if somewhat polite bass extension. The treble was very well behaved also with very little harshness and unwanted sibilance.

Making the Nad HP-50 sound fun

Whilst doing a decent job powering the Primes on high gain setting the One seemed more at ease and able to stretch its legs with more lower impedance cans such as the NAD HP-50 which sounded more aggressive and engaging with excellent bass weight (a dynamic trait that can also be found in the DX90 with the same DAC). That is something indeed given the HP50’s normally flat tuned and linear sounding signature. The match had certain likeability and a definite musicality and pace which makes this a solid match for hard rock/AOR. Vocals are clear, sibilant free and treble once again has little or no peakiness. That little added bit of bass weight and slightly thicker lower mids make it just right for solid rhythm and bass guitar work. Check out Lana Lane’s organ driven solo from Gemini’s “You can never go home” – excellent low end definition and a speedy mid section that sounds convincing and downright fun. Nap HP50 and fun.. an oxymoron that I am heartily engaging in.


IEM’s that I normally use during testing such as the VE6x, Westone 4, the FAD Heaven VIII all performed excellently on low gain with a noise free and black background. Noise floors were low and volume control was precise with no perceptible channel imbalance at low listening levels. The relatively natural tones of the One really matched well with the clear and clean Heaven VIII and especially the expansive VE6X. The slight lack of treble extension or spark on the One though didn’t appeal as much with the less airy Westone 4. My best pairings where with IEM’s that had excelled in clarity and control but didn’t come across as inherently bright or thin.
Other convergence devices out there?

Creative E5

Whilst the Creative E5 is an awesome budget do it all DAC/AMP but it can’t hold a candle sonically to the smoother and more natural sounding Companion One. The E5 sounds relatively unnatural, particularly in the treble response which has far more sizzle and harder to match with than the more natural sounding Companion One. Whilst Bluetooth aptX is really the cutting edge now for wireless BT audio signals it still sounds relatively muted and lacking in detail compared to the One’s higher resolution 24/192 wifi streaming capability. The One also sounded more accurate tonally and comfortable performed with large headphones such as the Prime and HE400i even though the E5 is actually rated a bit higher at 600ohms than the One’s 300ohm impendence ceiling.

The Aurender Flow

The Aurender Flow is double the price and as a desktop DAC/AMP solution it superior in the fine detail and dexterity especially in a treble response which has superior extension but it can sound slightly more analytical and precise and less musical than the Companion One. Of course it doesn’t possess any wireless connectivity whatsoever nevermind wifi streaming and looks huge when sitting side by side the more svelte and portable One. It also has a few hours less in battery life and is a right bugger to pair and walk around with mobile phones or high end DAP’s give its “flowing” curvy form factor. In terms of resolution and the absolute finest in clarity I would go still with the Flow but it’s not the complete on the go package like the One.

Final Thoughts

The Companion One right now is probably the most convergent of convergence devices out there that makes a serious attempt at targeting audiophiles over gadget freaks. It is the only one right now I can think of that is capable of doing so much and as such the value for money in todays ‘do it all’ fussy media market is actually rather good at $595. The fact you can run it out of a Mac, PC, iOS or Android wired is already a big advantage but to throw in wireless at a high resolution capability is a definite edge for now. The direct wireless mode sounds superior to any aptX or Kleer device that I have heard to date and is half the price of the admittedly awesome Flow.

I do have to point out though that the wireless functionality does require a degree of understanding and patience and may not be for everyone if Apple is not your bag. DNLA is an uneven experience and with Sony it could stall, loop and reconnect at anytime. I do hope Celsus can get a comprehensive chart of Android compatibility on the site just to manage expectations for the huge Android market out there that could be convinced. Thankfully with Apple’s iOS (IPad), using Airplay, the Companion One is rather idiot proof and setup takes all of about 2 seconds and you are good to go. Anyone with an compatible iPad, iPhone etc will have think this is all too easy.

Jason might just be onto something here to be honest. Just about everyone I can think of can technically use this device right now on one or more of whatever source gadget they currently have and can get a step up in sound quality right away. It is indeed ahead of the curve in many ways but in today’s “ponoarized” debate that is also a curve without a clear ending. The endless mainstream debate on why you need hi res could end up derailing a device like this from being the blueprint or show case for how IT and hi res audio on the go can really work. The Creative E5 is one direction, it’s cheap, it’s got lots of bells and whistles and sounds ok wired or wireless. It is also dead easy to setup for all functions. The One is heading in the same direction as the E5 but on a much higher level. A level that as an audiophile I personally really enjoyed even though I read the manual a bit too much for my own manly pride.

By Marcus D

Leave a comment

Comments will be approved before showing up.