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Reviewer: Srajan Ebaen
Financial Interests: click here
Source: 27" iMac with 3.4GHz quad-core Intel Core i7, 16GB 1.333MHz RAM, 2TB hard disc, 256GB SSD drive, ADM Radeon HD 6970M with 2GB of GDDR5 memory, OSC 10.8.2, PureMusic 1.86 in hybrid memory play with pre-allocated RAM and AIFF files up to 24/192; Audirvana 1.3.9.10 in direct/integer mode, April Music Eximus DP1, Esoteric/APL Hifi UX1/NWO-M w. Bakoon BPS-02 battery-powered Audiophilleo 2, NuForce DAC-100 [on review]
Preamp/Integrated: ModWright LS-100 with Psvane tubes, Esoteric C-03, Bent Audio Tap-X, TruLife Audio Athena, Bakoon AMP-11R
Amplifier: First Watt SIT1, FirstWatt SIT2, ModWright KWA100SE
Speakers: Aries Cerat Gladius, Boenicke Audio B10, Voxativ Ampeggio, AudioSolutions Rhapsody 200 [on review]
Headphone amps: Antelope Audio Zodiac Gold/Voltikus, April Music Eximus DP1, ModWright LS-100, Bakoon AMP-11R, Burson Audio Conductor [on review]
Headphones: ALO Audio-recabled Audeze LCD2, Sennheiser HD800, Beyerdynamic T1 and T5p, AKG K-702; HifiMan HE500 & HE6
Cables: Complete loom of Zu Audio Event, KingRex uArt USB cable with Bakoon BPS-02 battery power supply
Stands: Artesania Esoteric double-wide 3-tier with TT glass shelf, Rajasthani solid hardwood console for amps
Powerline conditioning: GigaWatt PF2 on amps,GigaWatt PC-3 SE Evo on front-end components
Sundry accessories: Extensive use of Acoustic System Resonators, noise filters and phase inverters
Room size: 5m x 11.5m W x D, 2.6m ceiling with exposed wooden cross beams every 60cm, plaster over brick walls, suspended wood floor with Tatami-type throw rugs. The listening space opens into the second storey via a staircase and the kitchen/dining room are behind the main listening chair. The latter is thus positioned in the middle of this open floor plan without the usual nearby back wall.
Review Component Retail: $899 as reviewed

Rollers. Casinos are known to have special suites and tables for high rollers. Valve fanciers roll tubes. It's their take on a worthy gamble. But what about solid statesmen and women? By featuring 11 socketed opamps, the ASUS Xonar Essence One provides happy roly poly for disenfranchised transistor listeners. But before we roll out the red carpet, up the sleeves and get expectantly sweaty hot-swapping 8-legged black critters, did I really just say... you know, ASUS?

Isn't that the Taiwanese company whose computer products grace Europe's Fust, Media Mart, FNAC, Saturn and similar Electrical Avenue outlets? Isn't that the info tech giant whose name dropped a peg to become the greater half of Pegasus, the mythical winged horse of Greek legend? It is. What gives? Do you remember how keyboard/mouse maker Logitech acquired Squeezebox maker Slim Devices years ago and then in-ear headphone maker Ultimate Ears?
"Been a reader of your site for a long time. Great work. Love the reviews. I work for ASUS and handle PR in the North America region. In a few weeks we’ll be launching the Essence One Muses Edition. It’s a DAC with USB and S/PDIF inputs. Works up to 24/192KHz, USB mode is async, dedicated headphone amp output, line and balanced outputs. The internal opamps are swappable and for this special edition unit we rely on JRC’s Muses opamps.


"I’ve tried many and think JRC are on to something. It’d make a good unit to review. Due to the cost of the opamps retail price for the Muses edition will be more expensive than the Essence One standard edition. We’re looking at well below $1.000. I think we stand up quite well against any competition. Would you be interested in writing one up? We might even be able to do an interview with the R&D guys. We’re looking at expanding seriously into this market segment. This is our first attempt but we have a lot more coming. We’d welcome your feedback." - Rajinder Gill		  
Extreme Super Computer ESC2000 supports dual Intel® Xeon® Processor 5600 series and 18-DIMM slots with up to 48/144GB high scalability for memory intensive applications. Designed for Life/Medical Sciences, Engineering & Sciences, Financial modeling and EDA & Visualization, the ESC2000 has up to 896 GPU cores to cope with the challenges of specific precise calculation tasks.


Xonar Essence ST precision computer soundcard
  From the company's global website one learns that "although we started life as a humble motherboard manufacturer with a handful of employees, ASUS now is the leading technology company in Taiwan and globally employs over 11.000 people. We make products in almost every conceivable category of information technology including PC components and peripherals, notebooks, tablets, servers and smartphones. ASUS products have won 3.886 international awards and accolades in 2011 and company revenue was over $11.9 billion." High rollers? You needn't be a whale to bet on that.


It's telling but no surprise that their first product for the hifi market would be a USB-enabled D/A converter*. It's our currently busiest segment after all. The async 24/192 spec and 4V XLR outputs aim at the high end. The retail price not so much particularly since the unit includes headfi and preamp functionality like Burson's popular $1.100 we despise opamps HA-160D.
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* On their website, where might a computer company stash away a USB DAC? Under PC components > multimedia > audio cards. That's sensible given that computer speak calls a DAC an external soundcard. In the ASUS catalogue, X-Fi components are for gamers by the way while Xonar kit is for music.

With the Essence ASUS clearly are on a roll. Given their colossal resources I reckoned I'd not be alone feeling curious. What exactly had they wrought with their first performance audio unit? Rolling opamps would be an interesting exercise too. "We’ve got a kit of five different opamps we are planning to sell – we can possibly add some more into that for your review. I tried quite a few myself. So far the Muses have an edge in 'musicality'. I closed the lid after trying them with the Sennheiser HD800. They have a liveliness that reminds me of the AD825."

Chip away!
Let's get busy. Like US budget leader Schiit did for their Bifrost DAC, ASUS opted for the C-Media CMI6631 USB2.0 processor with 32-bit/192kHz capability. An AKM AK4113 S/PDIF receiver manages the coaxial and optical inputs at 24/192. An Analog Devices ADSP-21261 3rd-gen 32/40-bit floating point SHARC processor handles DSP.


Twin 32/192 BurrBrown PCM1795 converters promise 123dB of dynamic range and improved clock jitter tolerance. The Essence One's selectable "world's first 8 x symmetrical upsampling" means that 44.1kHz-based sampling rates are upshifted to 352.8kHz, video-standard 48kHz-based rates to 384kHz. Hence no asynchronous sample rate conversion here. A 12MHz crystal clock handles USB, a 24.576MHz clock S/PDIF. Oscillators for the 44.1kHz and 48kHz sample-rate families run at 45.1584Mhz and 49.152MHz respectively. The multi-layer PCB sports twin grounding layers and full separation of digital and analog paths to eliminate cross talk. The power supply supports all international voltage ratings and has "wide margins for overvoltage/undervoltage conditions" [should avoid transformer hum in off scenarios - Ed].
Chinese Chime of the Tiger emblem
  Plenty of Wima FKP2 and FKS2 capacitors create audiophile cachet. ASIO 2.2 support for 64-bit Windows promises bit-perfect output. For that the Essence has its own discrete LED indicator aside from sample-rate lights for all frequencies between 44.1 and 192kHz. Dedicated Alpha volume controls for the 2V/4V preamp and 7Vrms headphone outputs are a unique wrinkle. One can set signal strength for speakers and headphones independently. But who'd use both at the same time to warrant such largesse?

Which gets us to the swapamps. The standard Essence uses 4+1 NE5532 opamps for I/V conversion on XLR/RCA and headphone paths respectively, 2+1 for LFP buffering on the line-level/headphone paths, 3 for the XLR/RCA buffer and one fixed LME49600 as the headfi output current buffer. The TI chips are thus the swapamps. The NJR/JRC Muses opamp exists as version 01 (dual JFET input) and 02 (bipolar input). Which one had team ASUS selected? And if the Muses were considered best to give this edition its name, what were the other options?

"As user taste in tone character varies, dedicated audiophiles often choose to change opamps to fine-tune performance, something the original Essence One supported with its 11 swappable parts. This proved highly popular, leading our team to extensively test over 100 different opamps to explore the finest combinations. The six opamps deemed most unique in their sonic impact were selected to be part of the Xonar Essence One Plus Edition. It combines the original Texas Instruments NE5532 with four TI OPA2132PA and two NS-LM4562NA for five customization options". [NJR/JRC Muses opamp 01 with dual Jfet input at left.]

Those were the cards for the Plus Edition. What hand would be dealt for the Muses?