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View Full Version : Asus Xonar Essence One external DAC/HP amp



AlfaGTV
16-07-2012, 19:26
Recently aquired one of these and have found it to be a very good DAC combined with a decent headphone amp.

It accepts input in the form of USB and SPDIF in either optical or electrical form. When using the USB inputs it works well with Windows (needs drivers) and Mac OS X 10.6 and newer and also newer Linux from my understanding. The control light for 'Bit Perfect' will not light up however, if not using ASIO output under Win.

On the front panel you have controls for Power, Upsampling, Input select, Mute and then two dials for controlling the output volume individually for the anlog out's, both balanced XLR and single ended RCA, and also for the headphone output.
The Upsampling function upsamples all inputs to 32bits and 384KHz or 352,8KHz depending on source sample rate. That means the signal sample rate is only doubled or quadrupled, what ASUS calls symmetrical upsampling. Based on tests using software upsampling on the computer i have always had the best impression of upsampled music using this form of upsampling so i like the idea!
In Asus implementation the Symmetrical upsampling makes the music seem a little overly polite though. Some get the feeling that it rolls off the higher frequencies, and maybe we are hearing the same thing but describe it differently.
One small gripe i have is the fact that you cannot set analog out to a fixed setting which means the volume pot is always in the signal path. I cannot hear any obvious disadvantages when playing music though.

So, what makes this different from other USB DAC's then? Well, first it sports a pretty good USB receiver chip which allows asynchronous transfer. (Receiver controls flow of data stream, instead of host)
Secondly you have the option of symmetrical upsampling.
Thirdly it is designed for neurotic audiophiles that like to tweak their hardware!
All OP Amps (nearly) inside is easily replaceable for customising the audio to you liking! And they are not few, 11 of them in total.
And last but not least, the unit is displaying excellent build quality and sensible design thinking. Built in dual mono style the unit sports dual Burr Brown PCM1795 DAC units with Wima buffer condensators and other goodies.
A monster toroid transformer of about 40VA delivers all the current and voltage needed. The power supply is heavily regulated and should be able to support all functions without loosing it's breath.

So what does all of this equates to then? Well, in my opinion the DAC sounds on par with my Benchmark DAC1, certainly an older construction but also around 4 times the price for the ASUS unit. Oh, i didnt mean they sound the same!
The Essence One plays music with some more blood and flesh, perhaps a little more laid back than the Benchmark. As i am used to the DAC1 i thought the Asus unit a little tired and not so engaging at first. After a few hours of good foot tapping though the Asus unit felt relaxed, highly resolving and so sure of itself it didn't have to flex muscle all the time.
As a small experiment though i tried some opamp rolling in he unit. The first four opamps (NE5532) serves as current to voltage converters, the signal is then sent to a pair of NE5532 serving as buffer opamps. These six are common for all audio output, and i shifted the buffer OPA's for one of my personal OPA favourites, the National Semiconductor LME49720NA. This had a clear impact on the audio delivered from the Essence One, if it was good before it now betters my Benchmark. The sound became more engaging without being tiresome, resolution improved, and for some reason music seems to have better timing. That must come from better resolved bass, i can see no other explanation.

Now this is my opinion on the Asus Essence One. Do anyone here have experience of this unit? Please share!

Regards /Mike

realysm42
17-07-2012, 08:15
I used to have the internal pci sound card; it was a great upgrade from what I had before, never played with the op amps but I was really happy with it's performance.

DaveK
17-07-2012, 09:29
I used to have the internal pci sound card; it was a great upgrade from what I had before, never played with the op amps but I was really happy with it's performance.

Ditto, but in my case I still have it in place in my home build HTPC - great gear IMHO.
Dave.

AlfaGTV
17-07-2012, 20:44
Thanks for the input guys! I also have a Essence STX soundcard in my music PC, which to me sound very good for an internal sound card. That one has also got some LME49720NA OPA tweaking! ;)
As good a sound card as it is it not really in the same league as the One, however. At least not in my implementation, that is.

I didn't put the pen to paper regarding the headphone part i realized. As i spoke of earlier, it sure does manage to power most any headphone on the market today. The audio quality however is merely "quite good" when compared to dedicated headphone amps, such as Little Dot MkIII or my favourite, the Lehmann Audio Black Cube Linear Clone which i built for myself.

It does sound calm and relaxed, but overly so in my opinion. The Lehmann clone displays unbelievable punch and dynamics and really gets your juices flowing in a different manner. The One will probably get some different OPA's in that section later to see if can be improved. Issue is, it already has the LME49720 there, and i will have to try tofind something useful which doesn't cost an arm and leg.

I have ordered some opamps from fleabay to try out some other chips also in different positions. So ill try them out and make an effort to describe what i hear later!
Regards Mike