Asus Xonar ST Op-Amp testing - Lenghty
Jun 14, 2013 at 11:08 PM Thread Starter Post #1 of 1


New Head-Fier
Jun 6, 2013
Hello , I just thought id share my experience with testing equipment. This is my opinion only and take it as that . I also pre apologize for any miss grammar or such because im also not a professional writer.
I am not a professional reviewer but Im not the type to spend money on something that wont give me improvements unless its justified -500 dollar power cable? not for me
My testing was done with A-B-C speaker switcher witch allows me to switch
between sources and even between op amps instantly so you can tell
what the real differences are between different equipment. And I don't know
what source im listening to so I make a real decision on the sound.
This is lengthy but if its needed to get my point across

My attempt is to shed some light for new users or people looking to upgrade.
Current Setup .
-Martin Logan ESL
-Emotiva Xpa-2 - Qsc PLX2 3102 - Crown XLS 1500
-Dayton 10guage Zip Wire ( the one reviewed in Audioholics)
-Dayton Interconnects - might upgrade to bluejeans -
-Asus Xonar essence ST - Advantage 2.2 setup EQ -Direct connection to amp Control of subs and front speakers separately.
-APC Surge protector with -70db noise filter -
-Computer has Xfx 1250W PSU-(seasonic) low ripple
-Pre-amp -NONE!-
-Extra subs - Definitive PF18" amazing clear bass - Definitive PF15" JBL 18" cinema Speaker- In my room the logans bass sometimes is to much but the subs give it that low low response. - subs not used when testing.

My last audio show was "The Show" at Newport ,CA . I actually met Peter Soderberg and spoke to him for a long time . I heard $600 to $130k speakers and I realized that people need to judge speakers before they know the price or brand of them.
After seeing the Amazing review on 6moons of the Asus One - Plus one - and Muse edition I realized that all I needed to do was upgrade my Op Amps and I would achieve what is "considered" great sound from a DAC ,

Many of you users have probably considered the Asus ST/ or STX because of its reviews and low price but probably think that products like Cambridge DacMagic Plus or M2techs Young are superior since they are audiophile brands, After some research I found that the M2tech is considered as good at $10k Dacs for a lot less , After seeing what chip it has as its Decoder I saw that it uses the PCM1795a Which is the same that Asus ONE Uses- Although the Asus ST uses the PCM1792 its pretty much the same .

OP AMP Testing : I decided to use/upgrade the Op Amps on my ST that come with the Xonar One Plus One - the TI – OPA2132 'Input Stage Only"which the reviewer said it was an amazing Dac for the Price and pretty much the same as the Muse edition. After doing on the fly A/B comparisons I found the TI – OPA2132 compared to the Stock 2124D Gave my logans more DB in the Midrange Vocals a instant and more airy extended bass as well as a lot more detailed highs specially on vocalist that say the letter "S" . The Original is a warmer Op Amp . The Soundstage though increased with the 2132 to give my Logans a live sound as well as it centered my Imaging perfectly . But that's because my midrange is louder which makes sense. Remember this is not im my head as I don't know what im listening to I just know what I chose as the better op amp.An advantage of the ST vs any other DAC is that it has an EQ that doesn't degrade quality , I use .05 and 1db increase at 8k and 16k since I sit less than 10feet from my logans and they are tilted back.

Results are awesome real difference , Do I prefer a live sound compared to a warm tube sound? im my situation YES specially because I increase my imaging . With these results I am tempted in spending $150 for Muse Op Amps - Although the OPA2132's are like 15 bucks and the reviewer said that there is a good difference in the Muse . At this point I trust the reviewer and I trust Asus with their decision making . Verdict is Get this Amazing card , Remember that most high end speakers are overly bright so there will probably not be a need for you to use the EQ settings I used. Logans are known for an already powerful midrange - This opamp is perfect so far and until I can get any science facts why anything else is better including records I wont upgrade, But I would love to upgrade to the m2tech because it looks so cool I would lose the ability to do 2.2 setup though unless I use an adapter and I wont be able to control treble unless I get a pre amp.  Would I be able to tell the difference between more expensive Dacs? probably but Is it a good difference? Everything above is subjective from person to person so its good to do blind testing.

Next test - Acording to Texas Instruments the PCM1792 is replaceable with the PCM1795a wich is 32bit decoding instead of 24bit. If I find a shop that can swap out the chip I will do it, Not sure if the card will even work but its worth a try , Better than upgrading the capacitors with I doubt will make any difference. I already have the chip got it as a sample in Texas instruments site for free.


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