Asus Xonar Essence One Plus Edition digital processor



Asus, ASUSTeK Computer Inc., founded in 1989 in Taiwan, is today one of the main protagonist of the 3C market: Computer, Communication and Consumer Electronics. For several years major international manufacturer of mainboards - one of the most important PC components -, Asus has progressively extended its business to several high-tech products: notebooks - today it is among the first seven worldwide manufacturers), graphic cards - it is the first worldwide brand in sales, and moreover optical storage, broadband solutions, servers, Pocket PC, products for networking, LCD displays, mobiles, PDA phones, solutions for Digital Home, GPS and Ultra Mobile PC. For a short time now, aided by the appearance of the streaming music, the brand has been spreading also in the audiophile world with the Xonar line: first with PC audio cards, then with a complete USB DAC, the Xonar Essence One. In January 2012, this DAC won the Innovations Award at the Consumer Electronics Show in Las Vegas in the audio category. Not satisfied with this success, in September 2012, the company launched, in occasion of the Top Audio Video Show in Milan, the Plus Edition version: an evolution of the basic model destined to the most exigent audiophiles or to the semi-pro market.

Technical Specifications

While the most part of the USB DAC converts the audio source at 192 kHz, the upsampling capability of the Xonar Essence One is: 44,1/88,2/176,4 kHz input towards the 352,8 kHz, and 48/96/192 kHz towards the 384 kHz (44,1x8=352,8 kHz; 48x8=384 kHz). Its audio processor, the ADI ADSP-21261, can handle a huge amount of data by upsampling the flow at 32 bits. The Signal-to-Noise Ratio touches the 120 dB and the highest is this ratio, the lowest is the noise level. Then has to be added the exclusive ASUS Hyper Grounding technology, which assures a reduced electromagnetic interference by separating the analogue and the digital signals. The standard power supply, based on a toroidal transformer and on local voltage stabilizers, gives a “clean” current feeding and avoids the classical noises caused by the traditional power supplies. Asus has also mounted on this device Wima FKP2 capacitors that are not polarized and are of top quality. To note the balanced XLR connectors: in this type of connection there are two conducers that carry signals of the same size but with opposite polarity. Hence, the noises that are induced along the cable path cancel out each other when reaching the destination load: here the pin 1 is the ground, the pin 2 is the hot pole, the pin 3 the cold pole. They will come in handy if you connect active loudspeakers.


The Essence One uses an asynchronous modality of data transfer, in order to solve the worsening of the jitter quantity due to the different velocity of data transfer between PC and audio devices. The integrated headphone amplifier has an AMP circuit with an impedance up to 600 ohms and is compatible with any headphone today available on the market. On the frontal are two control knobs. The smallest one handles the headphone volume, the other, bigger, controls the general attenuation of the volume. Both regulate two small but well-functioning Alps potentiometers. Near the big knob are seven control lights that indicate the different frequencies, from 44.1 to 192. At their left are three small buttons: the mute, the input with three control lights that signal coaxial, Toslink or USB ports, and the upsampling button. At the extreme left side the on/off button, a little bit noisy. On the back panel an IEC inlet – if you like you can use a different mains cable – and the three coaxial/Toslink/USB inputs and two RCA outputs.

To configure the PC there is a CD with the WMD and ASIO drivers.


With a S/PDIF port and the possibility of selecting the input, the Xonar Essence One can be connected to standard CD/DVD players and can directly provide music of high quality, without the need of any computer.

And here comes the real gem. Differently from the basic model, the Plus Edition is provided with a kit of six Op-Amps operational amplifiers in order to personalize the sound performances. The most exigent user can therefore get the best listening combination and configuration. The six standard TI-NE 5532 Texas Instruments can be replaced or combined with four TI-OPA 2132 PA and two NS-LM 4562 NA included in the Op-Amp Swap Kit Content. Therefore, it is possible to obtain five different configurations.


I try to explain where the do the replacements. There are four Op-Amps to convert the tension current (I/V). If you change them, there are audible effects on all the outputs, that are headphone, RCA and XLR outputs. There are other two Op-Amps that act as output low-pass filter. Also for them, the change produces effects on all the outputs. Asus gives clear explanations about the operational changes and provides a table where the audible effects are explained and compared.


Taking out and inserting the Op-Amps in the slots is simple although I suggest to use the provided tools. Trying to understand the sound differences is more complicated!


I have to hint at the manufacturing care and rationality. The device costs about six hundred euro. The making, sumptuous if compared with other more expensive DAC, makes foretell how the company works. By unscrewing six small screws, with the included screwdriver, you can see that practically there are two chassis, one inside the other, to avoid vibrations and various interferences. The interior is really well done: in my opinion, the designers have carefully analyzed the optimal signal paths and this always affects the sound quality. And when the circuitry is neat, like here, it is easy to change the components in case of any faults.


I like one thing in particular. This DAC had won an important award but what have done the designers? They have tested many other Op-Amps to get better performances!

Taiwanese designers of an industrial giant that deals with other and more profitable activities.

Hat off! I hope that some hi-fi manufacturers read this article, or this paragraph. And think about.


Listening session

Here below the table provided by Asus that you can also see in a wider version in the photo gallery at the bottom of the page. These are the combinations that we can have with the Op-Amps of the Plus Edition version. The 4+2 TI-NE5532 are standard: therefore five different sound “tonalities”. With other operational amps, you will get further nuances.


Nuances, the more suitable word. Actually, you can listen the impression described very well by the Asus technicians. The “plain” version is open, with a good image. The female voice, that is more or less the medium range, is timbrically correct, maybe too forwarded. The high range is not high-pitched, the bass is there, fine, and with some recordings it stands out. A few details, sometimes less evident, and the general musicality can rightly be different from other DAC devices. The reference in this case is the North Star Fluxio that I have tested in the same period. For honesty, I must say that a direct comparison has no sense, since the Fluxio costs three times more. Anyway, inserted in my system and in a higher-level system, with a PC as a source, the Asus behaves very well, always giving a correct sound.


Obviously, I have changed the Op-Amps in all the suggested combinations. Undoubtedly, there are some changes since you can get a brighter sound, more detail, a wider soundstage, or a less detailed sound with less bass, or a more powerful bass and less detail. I quite agree with the table impressions. The problem, in my opinion, is to find a sound typology of the DAC that can better integrate with the system. Or is it just an opportunity? Probably the Asus technicians have taken into consideration the exigencies of many audio enthusiasts, maybe the younger and more orientated to PC, digital world, streaming music and that have no problems in experimenting and changing some operationals. It is harder with the hi-fi traditionalists. I said young people because usually with less money and this Essence One Plus Edition offers a lot at a reasonable price. But also for whom has an old DAC not updated, maybe without volume control or headphone output.


By the way, I have tested the headphone output with a Denon AH-D5000, 25 ohm, and one AKG k 501, 120 ohm. The two headphones perform quite differently. The Denon has a very fine midrange, the trebles slightly attenuated, but for me too many basses. The AKG: trebles barely attenuated, the mid not so fine and the low range less powerful, but you can listen for hours. These are the features I have noticed with the Asus: also the headphone output has a good correctness. The only problem could be the absence of a remote control, but if you use the headphones, the system is quite close.



Who could purchase this USB DAC Asus? In my opinion, different typologies of buyers.

The classical hi-fi enthusiast that, by connecting it at the digital output of his player, wants to improve or update the source. If he is lazy or does not want to change the operationals, it is sufficient a friend’s help. After all, it is quite a funny and satisfactory game.

The crafty enthusiast that probably writes on forum where the change of Op-Amps occurs daily.

The disenchanted enthusiast that has no problems in eliminating the amplifier and connecting the DAC to amplified loudspeakers.

The enthusiast that wants to change the old converter and had thought of buying also a headphone amplifier.

Who is getting enthusiast of the hi-fi following the wave of the streaming music and wants to assemble a small system of a good level.

Who in the semi-professional sector runs a small studio, even if this is another matter.

Anyway, what at the end will unite all this users, is the purchase of a very interesting product, a product that is well engineered, well made, well performing and that allows upgrades at an absolutely not exaggerated price.



Official technical specifications

Audio Performance:

Output Signal-to-Noise Ratio - A-Weighted - Front-out:120dB

Output THD+N at 1kHz - Front-out: 0.000316% -110dB

Frequency Response -3dB, 24bit/192kHz input:10Hz to 48KHz

Output/Input Full-Scale Voltage: Balanced Output : 4Vrms Vp-p

Unbalanced Output: 2Vrms Vp-p

Headphone: 7Vrms Vp-p

Bus Compatibility: USB


Audio Processor: C-Media CM6631 High-Definition Sound Processor

Sample Rate and Resolution

Analog Playback Sample Rate and Resolution: 44.1K / 48K / 88.2K / 96K / 176.4K / 192KHz at 16bit/24bit

S/PDIF Digital Input: 44.1K / 48K / 96K / 192KHz at 16bit/24bit

ASIO 2.2 Driver Support: Hz at with very low latency

Upsampling capability: Up to 352.8kHz - 44.1K 88.2K 176.4KkHz input or 384kHz - 48K / 96K / 192KkHz input, 32bit

I/O Ports

Analog Output Jack: 2 x 3.5mm RCA jack,1 x 6.3mm RCA jack, 2 x Balanced Output XLR, 2 x Digital S/PDIF Input: 1 x Coaxial, 1 x Toslink, 1 x USB Input


Driver CD x 1

6.3mm to 3.5mm stereo adapter x 1

Audio Precision - AP test report x 1

USB cable x 1

Power cord x 1

Op-Amp Swap Kit x 1

Dimensions: 261.33x60.65x230mm WxHxD

Official Italian dealer: to Tedes website

Official current price in Italy: 629.00 EUR

Associated equipment: to Ulisse Pisoni's system

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by Ulisse
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