Review : Asus Xonar Essence ST

The Asus Essence ST is the best stereo PCI card that Asus sells. Frankly the name is a bit odd, given what else is called ST. However, we shall not judge them for the unfortunate choice. Let's hope that is the only bad one they made.

So, how does it perform?

As far as all reviews seem to say, pretty good.

Thus when my sample arrived, it was already too late for me to add much to the smattering of praise the card has received. Specially given the card has been around for about four years now.

But since this was a review and since I had to start somewhere, measurements were it.

Hacking together a connector was 5 minutes work, and soon I had some RMAA graphs to look at.

Very good, almost textbook-perfect behaviour. The card, unlike the DX I reviewed earlier, is much closer to stated spec than one would give a manufacturer credit for. Consumer-grade manufacturers have a habit of using the chipset specification as the final selling spec, however we know from experience that the final performance depends heavily on the implementation of the chips.

The card sat for about two weeks after I received it, waiting to be installed and then it took another two weeks for me to get around to writing the review. I was hoping it would be because I couldn't unplug the card from my system because of its virtues. Not, but not bad either. As you will soon see.

Anyway this is what the card looks like, with the cover on.

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Straight away one can see good details. Fine Gold capacitors, a respectable audiophile selection - though personally I would have gone for the KZ line which is even better. However the FG is good enough for the card. Also one sees OSCON capacitors on the digital and aux power filter stages. One can glimpse some copper shield between analog out and all other sections. This should be handy in a noisy PC (not acoustic noise, but electrical noise).

Here's the bum. Very uninteresting, except for the bit where you can see the digital output has a separated ground. Fat lot of good that does you, as there is no ground plane anyway.

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And here's the nude shot. Hmmm. The shielding is kind of incomplete, because it is made of two pieces of different metals, and with a gap. One would prefer a proper RFI cover, but hey, it's a 9k card. Let's not expect miracles.

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Let's go over her bits.

This is the I/O bracket.

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RCA line-outs, headphone and Line in on 1/4 inch jacks (6.35mm for you metric freaks). Combo jack for coax and optical digital output. The plating is not very thick on the RCAs. Those with springy and expensive audiophile plugs, stay away. You will wear the plating down in a few weeks if you switch cables often.

The digital output is capacitor coupled, not a proper transformer-coupled output.

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Expect slight degradation in ground noise when using the digital output. We'll see how much, but later. It does have digital pass-through. I did not test the Dolby Digital encoding. Knowing Asus driver implementation of this feature, I have no doubt it works well. However it would be sad to buy the card for that as the much cheaper DX offers encoding and is equally adept at the task. So if you have a digital input on your speaker/HT and need an encoded signal for surround gaming in legacy games (no other earthly reason to need it) the DX is the better choice.

Every output is relay-activated.

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The relays are used to suppress pops at switch on and off, and also turn stages on one by one. Excellent design choice and one strong reason to get this card if you have expensive speakers. These are also the reason that the ST needs a Molex connector. Not enough juice in the PCI slot to run all of those clickers.

The controller is the Asus AV100.

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A rebadged C-media controller, reasonably competent and with a reasonable range of DSPs. AFAIK you can't flash the controller and use the DSP with custom plugins, only the ones Asus bundles by default. I did not test the DSP, either this time or in the DX review earlier. And the driver panels are identical to the DX so I haven't bothered with putting them here.

ADC is the Cirrus 5381.

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One solid reason for its impeccable performance in loopback mode is the presence of a great ADC. Obviously this also means recordings will be of a high quality. You can't use it for pro recording if you like some hardware DSP, but then the C-media controllers are limited to running DSP in 48KHz mode only so it's not really that big of a loss.

DAC is the PCM1792 by Burr-Brown.

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A very competent DAC, one of the best stereo units in current production. Fortunately the card does not disable the analog output when the digital output is engaged. This was an issue in the Xonar DX when I reviewed it, and thankfully it is not so here so it was very easy to compare the sound quality to the (far more advanced) Buffalo DAC based on the ESS Sabre 9008.

The analog filters use two NJM 2114Ds to convert the current output of the DAC to voltage, and this is buffered by a LM4562 for analog output. The National chip is very difficult to photograph.

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All opamps for the output stage are mounted on sockets, so should be easy to swap out. I would recommend changing out the 2114Ds immediately. We can see lots of relays, so obviously switching logic is used to turn on stages only when needed. This is not trivial. Lower current draw typically means less load on the power lines, and thus less ripple and noise.

Finally the hidden bits, we have a multipurpose I/O jack at the back and this can be used for additional D/A outputs. The Molex here powers the relays (and other stuff maybe).

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There is also an AUX/CD analog in and the Front panel connector. Neither was tested. Nor was recording quality. I only checked analog and digital output, as that is what 99% of the paying public will be using.

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So let's get to the tests. Here is one pic (Large!) summarising all important RMAA tests. You can skip this and the next pic if you can't read RMAA graphs. Be happy to answer any questions you have on these. If you choose to do so, the result can simply be summed up as excellent and close to spec. You may have to save the picture or view it on a new tab to be able to read it properly.

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Basically, the loopback mode was the best (usually always is, but useless as you never use it like this). Three sample rates were used - 44Khz native, 96KHz native and 44KHz upsampled to 96KHz (non hi-fi mode).

I went head-to-head against the Delta 66, a card that is now over ten years old. It put up a strong fight and was not at all embarrassed by the newcomer.

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The output of the Delta is heavily modded with Black Gate NX capacitors and LM4562 opamps, but its power filtering stage is nonsense. The DAC/ADC combo chip is also an antique piece by any standard. However it still delivers far better than its spec, and is a very capable piece of hardware after the mods. The results on the left belong to the STX, the ones on the right to the Delta.

The card was compared to the analog output of the modded Delta66, the modded E-mu 1212m and the Buffalo DAC (a DIY product of Twisted Pear Audio, assembled by yours truly).

The card's digital output was used to drive the digital input of the Buffalo DAC when that comparison was made.

Music used was primarily male and female vocals. I did not get as far as the instrumental tests which I use after ensuring the product is able to deliver on the vocal tests.

The ST has a very clear, detailed and transparent sound. It is able to convey all the information in a piece of music faithfully. All however is not that well.

Compared to the Delta 66, the Essence STX has much more detail and transparency. One can hear deeper into the mix, and the upper midrange is far clearer. I would have no issues recommending it as a card to mix with if you do not need DSP or routing features built into pro cards. I use the Delta as a pro card and unfortunately need the much better hardware mixer in it. The Essence has a more limited mixer, even if it is thankfully based on hardware and not dependent on WASAPI or kmixer.To access the hardware mixing feature you have to switch to ASIO mode. In this mode the volume control does not work, as the mixer is limited in resources. The Delta 66 has no issues using its main mixer in ASIO mode so is a better choice to run professional active monitors off of.

Compared to the E-mu, the fight is very close. What the E-mu loses in detail it makes up for in timing and rythm. The digital output of the E-mu is also far superior, run off a dedicated chip and transformer coupled. Since that is how I use mine, the Essence will not find its place on my main rack. In this comparison the output of the ST began to show its characteristics, as now it was connected to my main speakers. For lack of a better word, the voices were sterile and flat. The space and stage depth were less than what the E-mu was able to convey. I don't like being too subjective about things, but the sound was too clinical. And I'm usually a fan of clean sound, but this was simply too little of the music and too much about sounds.

Final head to head was against the Buffalo. The issue here was the noise introduced by the loop between the ST (due to no transformer on the output) and the Buffalo, which shared mains ground at two points. I noticed about 4dB of degradation between this setup and my regular setup using the E-mu. However even with that fairly significant handicap, the Buffalo left the Essence biting the dust. The sense of timing fell apart, and there was absolutely no stage depth at all. Voices sounded dry and this kind of lines up with lots of other similar comments on forums and in some reviews. I would obviously not pair a 7k source with a 1.5L speaker, so it was a bit of an unfair comparison.

This is a quick shot of the testing facilities.

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At this point I'm still putting it back together, hence the topless PC. The monitor is only used to see playlists, and it is enough for that. RMAA tests were done in the 'computer room' which is not usually open to public viewing (thank God for that).

Now the big questions.

Should you get one?

If you have a (analog) system which totals about 35-40k and you don't have a source, get it with your eyes closed. It is far better than most CD players at three times the price. Once you have more than about 25k to spend on a source, things begin to look bad for the ST. There are also enough options for budget DACs at that price.

Should you get the PCI or PCI-E version?

Well according to John Atkinson the STX measures better than the ST. Which is a bit of a bummer for me, except I got slightly better results than JA when comparing to his ST results. I can only conclude his PC power supply is rubbish. The PCI versions *will* use the -12V supply from the PSU, and a good supply will result in a lower noise floor.

How do I know I need one?

If you have a pair of cheap little PC speakers, forget it. Only after you plunk down the dosh for a decent pair of monitors (Audioengine 5, M-Audio BX5, and so on) should you think about this. For cheaper stereo, get the Xonar DX. It's good enough a mate to not embarass even very good speakers like the Audioengine 2. If you need multichannel, forget it. The DX offers good enough digital multichannel for pretty much anything, decent enough analog multichannel for expensive (15k) analog multichannel systems. For more pricey HT needs, the Xonar D2/D2X is the way to go.

Why didn't you test headphones/DSP/recording/(insert your favorite feature here)?

Because I was testing the way I figured most would be using it. I do admit a lot of people would be using it with cans, but the fact is that I don't have and never will have a decent pair of cans, I can't use them for medical reasons. So my apologies to headphone users, though I'm assuming that since this card is already a few years old most of you would have already sampled it.

For the rest, bug off. there's enough reviews telling you how to distort the sound to hell with DSP and other nonsense.

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To sum it up, for about 9k you can't really expect a better source. The cheapest usable CD player in the country is about 20k, and even that will not have a digital input. Things begin to get complicated when you consider that for that much money you could get a nice Far Eastern USB DAC. However my experiences with that genre of products (including some aggressively marketed big brands) leads me to believe the Asus is indeed the better product. It's built better, sounds better and is far more consistent and reliable than any other sound source under 10k. Definitely recommended.

Disclosure: The card sample for review is the property of Asus Computer and is returned after review.
 
Great review!
Your findings are similar to mine with the STX. It really is a pretty decent budget source.
Also the Digital out of STX too is no better than a onboard Realtek s/pdif.

BTW, the output coupling capacitors aren't really needed. I bypassed them & the resulting DC offset is still under 2.5mV. May be you can try that.( Didn't notice that this is a review sample, so maybe not)

P.S. I need to spread some reps before I can rep you again.
 
@titana - I need my source to have zero offset as all my amps are DC-coupled. With a gain of roughly 30, a 2.5mV source offset becomes 75mV at the speaker. This is not really acceptable to me.

Where the DX/ST/STX score over the onboard out is in surround gaming. Of course one could simply get a Gigabyte board where the onboard supports Dolby encoding out of the box and then yes, you will not need a separate soundcard for that feature.
 
My amp is DC coupled too(Gain 9) but it uses a opamp servo to zero the offset, no such provision in your amp?

BTW, did you roll any opamps?
 
No, and no.

I find the servo itself to be a source of instability, specially with high gain configs. I need the gain or speakers don't work properly. As it is I have an amp generated offset of about 25mV (including its own gain), can't risk more.

The Buffalo DACs output stage generates no offset, so is coupled directly to the power amp (no cap on output).

I didn't roll opamps because I don't have DIP opamps. All my stock was SOIC, and I used up all of mine while modding my cards. Actually, I have no spares now at all.
 
Good review Cranky. It was a pleasure reading it . Would love to see a review of the new Asus Essence One DAC from your side . :)
 
Thanks Faheem and yes, am looking forward to reviewing it. I did hear a little bird say that I should look forward to one pretty soon.

I hope the Asus engineers upgrade their listening equipment. The ST is a decent piece of hardware that could have been optimised with some tweaking at the listening test level. If you look at some of the mods available, there is plenty of room to grow when it comes to the card itself.
 
As usual, nicely done cranky!

PS: ^^ The same little birdie says we can actually look forward to a review each by both of ye audiophools pretty soon. :)

PPS: Eagerly awaiting the review as I am in the market for a CD transport and a DAC to go with it. Being the cheap-a$$ audiophool I am, I'd want that DAC to also sport a USB port. The essence one looks like a decent upgrade from my current Maverick Audio TubeMagic D1.
 
Analog or digital?

The analog output should be slightly better on the ST/STX.

The Digital output of the Juli@ will be miles ahead.
 
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