Celsus Sound Companion One portable headphone amp/USB and Wi-Fi DAC review

Jason Lim, the man behind NuForce (which he has recently sold, by the way) just doesn`t seem to run out of ideas. Just recently, he has started two new companies: NUPRiME and Celsus Sound and it looks like we are going to witness another stream of highly innovative and even unique products. The Celsus Sound Companion One portable headphone amp/USB and Wi-Fi DAC is a brilliant device packed with features and cutting edge technology - all in one very small footprint. The photos and words cannot convey how beautiful this unit is in reality. It comes packed in a nice box with ALL the necessary cabling and even a leather travel case.

From their website we learn that the Celsus Companion One features a high-performance headphone amp with better than 115dB signal-noise ratio. The USB DAC, uses ESS’s ES9018K2M DAC, decodes up to DSD128 and 384 kHz PCM audio formats. A built-in Wi Fi network allows Companion One to be used as a media streamer capable of PCM 24bit/192kHz streaming. A digital Toslink S/PDIF and one 3.5mm analog output connect Companion One to a wide array of devices.

The Celsus Companion One is the world’s first high-performance DAC that supports both USB cable and wireless connections to Windows, Mac, Android (*OTG) and iOS devices. Another world’s first is the Companion One’s ability to decode and stream 24bit/192kHz music files. Thus the user enjoys the highest quality desktop USB audio playback available and, with the push of a button, streams music from connected devices with better than CD-level resolution.

With asynchronous USB audio clocking via two internal high-accuracy low-jitter clocks for 44.1kHz (88.2/176.4/352.8) and 48kHz (96/192/384) sampling, the Celsus Companion One optimizes USB digital data transmission for ultra-low-jitter performance with better than 115dB signal-noise ratio.

The Companion employs an OPA1612 for I/V conversion and an AD8397 for voltage gain and current buffering sufficient for driving the most problematical headphones.

The Celsus Companion One’s curved frame is machined from a single block of aluminum and has top and bottom gorilla-glass covers.


USB Audio:
Supports Windows, MAC, Android (version 4.2 and above with OTG cable) and iOS (iPhone 4/4s, iPhone 5/5c/5s, iPhone6/6 Plus,iPad/iPad2/iPad  Air/iPad  MINI)  devices. 
PCM audio: 16/24/32-bit audio data, 44.1/48/88.2/96/176.4/192/352.8/384 kHz native sample rate.
DSD audio: DSD64 and DSD128 native decode.
Asynchronous USB audio clocking with two internal low-jitter clocks separately for 44.1kHz (88.2/176.4/352.8) and 48kHz (96/192/384) sampling.
Switches between USB High Speed (480Mbps) and Full Speed (12Mbps)
Extremely low latency 
Supports ASIO
Supports Windows, Mac, Android (*OTG) and iOS devices
WiFi Audio – Uses 2.4G wireless network and supports DLNA, Airplay and Qplay. Supports all commonly available  music  file  formats, including FLAC and WAV. Decodes and streams the highest PCM 24Bit/192KHz rate over WiFi. Connects  via  AP (one-to-one using Companion One WiFi SSID) or Client (using existing WiFi network)
Wi-Fi Streaming:
Supports PCM format: 16/24-bit, 44.1 / 48 / 88.2 / 96 / 176.4 / 192KHz
Digital: Toslink S/PDIF
Analog: 3.5mm
Volume Control: 100 steps
Gain Control: 2 levels, for earphone impedance of 16 to 300 Ohm

Along with the Companion One I have received the Gramo One proprietary 16 mm Celsus Sound open-back in-ear headphones. Let me just say that these tiny headphones offer excellent sound for the size but obviously they cannot even hint at what the Companion One is capable of in terms of sound quality. By all means they are a “great companion” for the Companion One - on the go. In a separate packaging the mini stereo jack to RCA stereo adapter cable was also supplied.

In use

The included quick start guide and the manual are short but connecting the Celsus Companion One proved to be a straightforward and easy job. Everything worked flawlessly and without “hiccups”. For the listening test I have connected it to the laptop and had to use the high gain mode in order to have a comparable output levels to other DACs I have had on hand.

The included accessories are:

Genuine leather carrying case (!)
Micro USB to Apple Lightning cable
Micro USB to Apple 30-pin cable
Micro USB to PC USB cable
Micro USB to Android OTG USB cable
Protective film cover and microfiber cloth (!)

The leather travel case is a great idea if we want to carry the Celsus Companion One around and make sure it doesn`t get scratched or suffers any other damage. Ok, the Gorilla Glass is tough and damage resistant but still...

Holding the Companion One in hand reveals this is quite a heavy unit, it feels refined and extremely well made which reinforces the feeling of a luxury gadget and not merely a simple portable audio device. The knob layout is clever and ergonomic, pressing them reveals they are mechanically sturdy which inspires confidence in the expected longevity of the product.

The Sound and some Music

Let me start by saying that the Celsus Sound Companion One portable headphone amp/USB and Wi-Fi DAC doesn`t only sound marvelous for the size but regardless of it. It even manages to compete with much more expensive bigger units - quite easily. Frankly, I was stunned by the performance levels experienced by this extremely elegant portable unit. Replacing the mid sized DACs I have had on hand with the tiny Companion One proved the latter can stand shoulder to shoulder with its bigger sized competition and perhaps even teach them a lesson or two. No matter how hard I find it to believe, the Companion One`s implementation of the ESS’s ES9018K2M DAC and the output amplification stages are apparently extraordinarily good; the sound just seem...well, kind of, mature. On a blind listen one could never guess the sound comes from a portable unit. Of course, I`m not suggesting the Celsus Sound Companion One threatens some upper class DACs but it would be fair to point out that it plays in a league well beyond its price class - period. There is nothing that would suggest its portable nature, the sound unfolds in front of the listener in authoritative and believable manner.

Also the emotional involvement factor is quite high.

Prior to auditioning the Celsus Sound Companion One, my first prejudice was: there is no way this unit will provide acceptable levels of bass quantity and quality. How wrong was I: the Companion One provides a very extended, firm, controlled and punchy bass that easily fools the listener into thinking it is being reproduced by a big (normal) sized DAC unit with a sizeable power supply section. The José James` “The Light“ track from his Blackmagic album (2010) is one of my favorite ones for many (musical) reasons and also useful for a quick test of the bass punch AND control. Obviously I am really familiar with this track and here, the Celsus Sound Companion One didn`t disappoint; quite on the contrary, it provided all the power, heft, depth AND control - as I expect from any serious DAC:

A few words about José James. He is a outstanding Panamanian multi-instrumentalist, singer-songwriter and producer, a three-time Minnesota Hall of Fame inductee as a member of Willie & The Bees, Shangoya, Ipso Facto and was voted Best Brass/Reed Artist at the Minnesota Music Awards in 1994. He was born in Ancón, Canal Zone, Panamá, he grew up listening to a wide variety of music like Calypso, Cumbias, Salsa, Samba, R&B and Rock N’ Roll. His first instrument was a nylon snare drum his parents bought him for Christmas, later developing an interest in the trombone. He began playing the Alto Saxophone at age 12, and at 14 was playing in the high school band, while studying music theory and classical flute at the Conservatory of Panama.

Moving into dynamic classical repertoire, the “Dance of the Seven Veils from Salome” (Eiji Oue - Exotic Dances from the Opera) was again rendered with authority and a deep, powerful and controlled bass reproduction. The hall dimensions and the instrumental 3D placement/focus were clearly portrayed in all three planes and gave a rock-solid impression. The tone and timbre of all the instruments were spot-on and the subjective “weight” was comparably good. The micro and macro dynamic responsiveness was excellent, the music sounded sparkling and alive.

The Jack DeJohnette “Music We Are” album (2009) is another great recording of extremely dynamic and exciting music. The musicians are all legendary in this genre. The ninth track, “White” (written by Danilo Perez) starts with keyboards, piano and some explosive drum and percussion punches by Jack DeJohnette. On many DACs, the percussion sounds brittle but with Celsus Sound Companion One it sounded much smoother but still open, it really felt neat. With good source, amplification and speakers, this album gives a spectacularly lifelike impression because it seems that the dreaded compressors weren`t “working hard” as usual. The “Seventh D, 1st Movement “ and “Cobilla” are my other favorites from this fantastic session. Overall, this album is a pure masterpiece and is strongly recommended to all music lovers and audiophiles alike.

Monday Michiru is a Japanese American actress, singer, and songwriter whose music encompasses and fuses a wide variety of genres including jazz, dance, pop, and soul. She is arguably best known for being a pioneer of the acid jazz movement in Japan in the early 1990s yet she has created her own unique style of music that transcends traditional definitions of the aforementioned genres.

Monday was born in Tokyo, Japan to jazz pianist Toshiko Akiyoshi and her then husband, jazz saxophonist Charlie Mariano. At an early age, she expressed an interest in music; she studied modern dance and ballet from age eight, and the classical flute for eight years. It wasn't until she went to the Interlochen Arts Academy that she discovered her true passion of singing.

Her Nexus album (2008) was also used for these listening sessions and the stand-out tracks for me are Epiphany, Candy, Sometimes, the funky Sands Of Time and the closing ballad On And On.  
Through the Celsus Sound Companion One her voice sounded soulful and enchanting and the rhythmic groove was fully maintained throughout the whole album. The acoustic instruments in particular sounded very immediate, alive and possessed sufficient levels of natural warmth.

Whatever I have thrown to this little unit it managed to chew without slightest effort. There you have it, after the iFi Audio micro iDSD we have another little giant: the Celsus Sound Companion One! 


The Celsus Sound Companion One portable headphone amp/USB and Wi-Fi DAC is one extremely versatile, well built, classy looking and on the overall unique device. The sound it produces puts many bigger and more expensive DAC units to shame and let`s not forget we are talking about a portable headphone amp/USB and Wi-Fi DAC. To have such performance on-the-go is a pure luxury and from all I can tell the Celsus Sound Companion One could easily form a basis of a very fine home stereo system - yes, it`s that good!

Highly recommended.