[Simcon]

The Xonar STX is worth every dollar ~$180 in the long run, so in the end I've decided to place my order on it instead of 1. my existing DGX soundcard + external amp or 2. External DAC+AMP All-in-one unit or 3. Upgrade my existing sound card with better Audio chip and DAC built in + external amp. The Xonar STX option is far better than the above 3 scenarios I mentioned in terms of performance to price ratio and upgradability.

Xonar STX is known to have a high end DAC that's comparable to some ~$1,000 DAC external units as most people say, and the built in headphone amp is pretty decent and capable to drive higher impedance headphones. Take $180 and divide the price by 2 and that's like $90 each for DAC and Amp for desktop/stationary use. The value is much better than any of the 3 scenarios I came up with above. Plus, you could always upgrade the 3 upgradable op-amps on the card anytime down the road to keep you happy and satisfied from the itch again.

I'd say that a O2+ODAC is a good alternative, but when comparing 180 dollar to 280 dollar, I'm not sure about that the value for money would be better in that combo. However the amplifier in the STX is somewhat unsuitable for easy-to-drive headphones, so it probably comes down to a question of what headphones you're going to be using. Prices in different countries can affect which alternative that would be the best suitable for your needs and use. With all that said, you're probably going to be happy. But the fact that you can change OP-amps pretty much seems more to be side-grades, rather than upgrades from everything that has been written about them in this thread.

 

[bcschmerker4]

Concerning the Texas Instruments® TPA6120A2's associated circuitry as installed, it appears that Audinst® may have done better on the HUD-MX2 USB 2.0 external DAC than Asus® did on the XONAR® Essence™ One™ external DAC and Essence™ ST and STX audio cards, as Audinst® achieved a 2Ω Headphone-Output source impedance (vs. 10.7Ω on the XONAR® Essence™) (see "Audinst HUD-mx2" in Head Gear -> Headphone Amplifiers -> Amp/DACs).  How did Audinst® achieve this low impedance; and can the necessary output fixes be retrofitted to the ST and/or STX?
 
(I've decided to upgrade my STX' op amps to dual National Semiconductor®/Texas Instruments® LME-49990MA's on a custom adapter PCB at the line-level buffer position due to the 600Ω load rating; and similarly-mounted Texas Instruments® 100 MHz op amps for the I-V, either dual THS4031's or a single THS4032 per channel.)

 

[stv014]

Quote:

How did Audinst® achieve this low impedance; and can the necessary output fixes be retrofitted to the ST and/or STX?

 
It can be achieved with an inductor connected in parallel to the output resistor, so the output impedance is low at audio frequencies, but is high at the RF range where the protection against capacitve loads is needed. This is common practice in speaker amplifiers.
However, I did not find the output impedance in the specifications of the HUD-MX2.

 

[verde57]

Quote:

 

Xonar STX is known to have a high end DAC that's comparable to some ~$1,000 DAC external units as most people say,

Let's not forget the easy mod to the oscillator TCXO, that can be done to the ST and STX. The result of that mod are spectacular!

 

[DICOM]

I apologize if these questions have been asked/answered already, and would certainly appreciate being told where to go ... URL-wise.
 
I have the STX and as of late it has been outputting a sound signature that is best described as sounding like a cross between an echo chamber and a fishbowl. I have RCAs running directly from the sound card to a pair of AudioEngine 2s. I'm using Windows 7 64-bit Ultimate, and my player is either JRMC or foobar2000. I have the output set to WASAPI event-style and have tried a variety of different sample and bit-rates, all without success. The driver and software is current.
 
Any help would be appreciated.

 

[Jerppane]

So I'm running the STX + HD650 combo.
 
I was planning to upgrade the op-amps on my stx, but with no experiment with them i tought i'd ask some advice here.
At the moment I'm running with the stock op-amps. I like the sound of the stocks quite a bit and i wouldn't like to change the sound signature that much

.
 
So which op-amp would work the best with the HD650's, improve the overall sound quality and offcourse give me a more enjoyable experience?

 

[L36i]

I'm running 2 LME49860NA. I upgraded back when i had my HD555s. The difference was huge vs stock OPs, the sound stage opened up and bass became more detailed and quicker. Treble got much cleaner at higher volume.

Mind you i had that experience with 555s, with 650s you might get even bigger difference. Although i have the ST, but they're nearly identical...

 

[Spastic]

I currently use my A700X's with my STX
 
Previously when using the onboard sound on my motherboard, there was quite a bit of distortion and the instruments in music sounded slightly muffled and cloudy, treble was not as clear as I would have liked it to be and the sound stage was clearly lacking.
 
However when I plugged my headphones into the STX, treble improved in clarity, sound stage reached auditorium level and distortion was non existent. 

 

[repman244]

Quote:

So I'm running the STX + HD650 combo.
 
I was planning to upgrade the op-amps on my stx, but with no experiment with them i tought i'd ask some advice here.
At the moment I'm running with the stock op-amps. I like the sound of the stocks quite a bit and i wouldn't like to change the sound signature that much

.
 
So which op-amp would work the best with the HD650's, improve the overall sound quality and offcourse give me a more enjoyable experience?

I would suggest LME49990 or THS4032. Since you're using the built in amp, you don't need to change the buffer.

 

[Tiramisu]

I was reading a thread about upgrading op amps on the Xonar STX over at DIYaudio, and a response to some of possible issues have raised some concerns:
 
 
Quote:

Originally Posted by counter culture
 
The soundcard is provided with the facility for changing the opamps because people like to change the opamps, it costs very little to socket them, and it probably swings a sale or two. The fact that people change them is indicative of the fact that people can't resist changing them, not that it results in any improvement or that there is any rational motivation whatsoever. People say that they can hear an improvement, but they hear these improvements under conditions which are known to result in unreliable observations. This doesn't stop them making the claims, or changing the opamps. That's people for you, or as I b'lieve they say in Yorkshire, 'There's nowt so queer as folk'.

If you could really get a significant improvement in measured performance by designing in different opamps, however, I think Asus would design them in. The NE5532s are cheap because they are produced in huge numbers, because they are very good.

If I had one of these Asus soundcards, I'd leave it as is. The only likely results of changing opamps are that the soundcard will run hotter, be less reliable as a result, may possibly oscillate and you will be £60 worse off. I think that's what AndrewT means, when he says 'don't'.
 

 
I was seriously about to order 3 pairs of LME49990 from a reputable source on Ebay but I'm being held back by some of the concerns I mentioned earlier. I've also asked about it in a new thread but no response yet to be made.
 
Quote:

Hi guys,
 
I'm looking for a stable op amp upgrade option for my STX sound card, and I'm eager to know if these LME49990 op amps are perfectly stable match with the Xonar STX for long term use. From sources I've gathered that says fast op amps like these may not work well with certain circuit boards, and I'm not familiar with electrical engineering background to find out the answer to my concern. Will someone with more knowledge or experience to have a say about this setup, please?
 
Thanks!

 

[gcwebbyuk]

Hi All, sorry if this has been covered somewhere earlier in this thread, but it is one loooong thread to hunt through!
 
I currently have an STX with 3 x LME49860NA op-amps.  I am really happy with the sound both through my AudioEngine A2s and Grado SR80is.
 
I am considering buying a DAC/Headphone amp to use with my laptop when sitting in the living room, and have been looking at the Meridian Explorer or the Audioquest DragonFly.  My worry is that I will buy one, and find it better than my STX, so end up wanting 2.
 
How would a DAC/amp of around £250 compare to the STX?
 
p.s. - I did ask this in a different section of Head-Fi, but didn't really get a response, and thought here might be a better place to ask...

 

[Tiramisu]

Quote:

I'm running 2 LME49860NA. I upgraded back when i had my HD555s. The difference was huge vs stock OPs, the sound stage opened up and bass became more detailed and quicker. Treble got much cleaner at higher volume.

Mind you i had that experience with 555s, with 650s you might get even bigger difference. Although i have the ST, but they're nearly identical...

Ok, so I figured I got nothing to lose by ordering 3 free samples of LME49860NA/NOPB from TI. Order was processed and sent on the same day, and next day delivery ETA from MN, US to BC, Canada, I'm impressed!

Just hope I don't get hit by customs, etc, but even then it's still fair bit cheaper than ordering them from a distributor. Either way, I think this is a step in the right direction. It's definitely an upgrade from stock op amps.

 

[Tiramisu]

Quote:

Ok, so I figured I got nothing to lose by ordering 3 free samples of LME49860NA/NOPB from TI. Order was processed and sent on the same day, and next day delivery ETA from MN, US to BC, Canada, I'm impressed!

Just hope I don't get hit by customs, etc, but even then it's still fair bit cheaper than ordering them from a distributor. Either way, I think this is a step in the right direction. It's definitely an upgrade from stock op amps.

 
 
*Edit: Impression of 49860 after ~10 hours burn in. (Burn-in Wavs + lossless recordings)
*Edit#2: Day 2 (~24 hrs)
*Edit#3: Day 3 (New Impression, new scores update, added Soundstage/Image new category to the review)
 
 
It's definitely lacking bass, like everyone else have noticed. It's NOT an upgrade
Edit#2: (It's a sidegrade) despite its spec on paper compares to stock JRC 2114Ds.
Edit#3: (It's considerably an upgrade) from the stock op amps JRC 2114D in (I/V).
I feel like I owe myself an apology for my past clouded judgement, due to all the colorations from the stock JRC 2114Ds; these are not superior in SQ. The more time I spent listening to the 49860, the more I understand its beautiful SS. It's closer to a linear response that's true to the original recordings, from low 20Hz to high 20K (monitored from digital analyzer processor in JRiver MC). I feel that the 49860 is easier and soothing to listen to in one sitting (5+ hrs), which it wasn't possible for me with the stock op amps (2 hrs max.) before taking a break. 
 
 
Background info about my setup:
I'm pairing with Beyerdynamic DT 990 Pro (250ohm) ~180+ hours burned in. Foobar2000 1.2.4 & JRiver Media Center 18 (Newest 18.0.158 patch) -> ASIO (bit-perfect) x64 -> Internal volume control at -25.00db. No EQ or effects. ASIO control panel set to 24bit/10ms. Headphone amp setting at "Extra High Gain" and everything tested in lossless FLAC/ALAC/APE/WAV codecs.
 
 
First of all, the perceivable difference in SQ/SS from stock to 49860 is very noticeable and in a good way for 49860. I think I've a pretty critical set of ears. My first impression when hearing the 49860 was that it sounded quite thin and transparent compares to stock.
Edit#2: (It's colorless/natural/flat sound signature - to me it's lacking personality and emotional responses, which makes me feel detached from the music that requires those essences to really move me.) It's missing that kind of full and lively sound as if you're listening at a live studio or in a reference room. 49860 didn't give me that kind of an impression, and it makes many of my favorite songs sound kind of lifeless, boring, less engaging, and believable. 
 
 
Clarity/Detail/Resolution/Positioning&Separations:
It's close to the stock but not quite. Both have much room for improvements, but I feel 49860 isn't as revealing as stock.
 
Edit#3: 49860 turns out to be one solid step above stock JRC 2114D in this whole category.
Edit#3: 49860 shows a natural and accurate dynamic response from the original recordings, without being overly boomy and harsh sounding like the stock. It presents a clean and fast sound. I also noticed that I could hear more micro details from recordings, and I suppose this is partially due to better controlled and defined bass response.
Stock = 7.5/10 (B) and the 49860 = 7.0/10(B-) 7.8/10 (B+).
 
 
Soundstage/Image:
The DT 990 Pro is well known for its soundstage reproduction, and the 49860 has brought my listening experience with it to a new level. There is more openness in the sound and more depth (3D) to the image. The sound is also more airy, and the soundstage is slightly larger all around (similar to a studio/reference room setting).
Stock = 7.5/10 (B), 49860 = 8.0/10 (A-).
 
 
Treble:
There are two sides to this. I can put it in a good way or in a bad way.
I'd say pairing 49860 with a particular headphones like the DT 990 Pro has an interesting result. It's a dynamic sounding headphone with slight emphasis in bass and treble frequencies. High frequencies is definitely its strong suit, and overall it has an excellent frequency response according to golden ears' target. I also noticed that the treble is slightly rolled off, and as a result it makes DT 990 Pro sounds darker  I can say the sound is smoother with 49860. For brighter headphones like DT 990 Pro/880/Q/K701/2, etc (peak from roughly 6~14K), this might seems like  is a good match. but it's at the cost of slight downgrade in clarity and detail. 49860 is the better choice for long listening session (2hrs+) with slightly less ear fatigue.
 
Edit#3: The high frequencies aren't harsh sounding as to the stock, and I don't have to use EQ to tame those treble spikes. Highs appears to be much smoother while still manage to show exceptional clarity and detail. 
Stock = 7.0 (B-), 49860 = 6.8/10 (C+/B-) 8.0/10 (A-).
 
 
Bass:
The bass hits slightly softer and has lost some of depth, weight, image, extension, and impact; these changes make listening experience less believable and engaging.
The most obvious sign is that the lack of overall bass signatures make the tonality in music sound thin and a bit dull. Since bass is such an important element in almost all contemporary song recordings today, I can't say I get a very satisfying listening experience from songs I'm familiar with. There were particular moments in songs that I expected it to deliver the climaxes in certain notes, but it isn't quite there. I would be over exaggerating if I say the bass is completely in absence, but it's not. The problem I find is that it makes some songs forgettable.
Edit#2: (The bass is present but its overall presentation is softer; It's a matter of personal taste. If you favour a flat bass reponse with less bass extension, this may be your cup of tea.) 
Edit#2: (I can feel it's smoother and just lightly well blend in with all other frequencies; I don't feel the bass is boomy from long listening session.)
 
Edit#3: (49860) - The bass is actually very well controlled and with better definition; it's tight and punchy, and there is an accurate dynamic to the bass response. The bass extension can go very deep and as low as the notes from the original recording without being overly boomy, and I'm monitoring this from my DT 990 Pro (Excellent sub bass response). There is just right amount of bass quantity, and an overall improvement in the bass quality. It doesn't present any coloration, so the overall SQ is much cleaner and more transparent. I also love the bass being more airy to my ears (30Hz~80Hz). It's definitely a whole new experience from stock, and I actually really like these changes for the better. *I'm still contemplating on buying LME49990, though. It's the high cost that's really holding me back, but I'm sure they're worth the price.
Stock = 8.0 (A-) 7.5 (B), 49860 = 6.7 (C+) 7.0 (B-) 8.0 (A-)
 
 
Mid:
I do not notice a significant difference in this category from stock. It's roughly the same or at least not perceivable by my ears. It is what it is from the DT 990 Pro and I don't hear noticeable changes for the worse or better. It's clear but not spectacular. It doesn't help with the slight recessed mid of the DT 990 Pro, but neither did the stock. Once again, It's not possible to make a A/B comparison, so I can only draw my conclusion based on my very recent memory just hours prior to the installation of 49860. Basically, it's about the same. However, I do notice the vocal is a bit smoother, thus less ear fatigue. For me, the vocal sounds less sensational. The result in the mid isn't as drastic as the treble. Overall, I would rate both about the same.
 
Edit#3: 
Because of those positive changes in treble and bass, this has made a noticeable effect to how the mid is presented. The mid is brought slightly forward from my DT 990 Pro. Vocal presentation is a step above JRCs. I feel that the vocal sound a bit dark. It's perhaps a bit more smoother, and the sibilience in female vocal is much less pronounced which is a tremendous step forward in perceived SQ. The vocal is very clear and transparent. I'm able to spot more micro details in the vocal than before, so these changes made me really like the 49860. Overall, it's an improvement over JRCs. I'm not saying everything is spot on and perfect. The vocal still sounds a bit laid back in certain songs from my DT 990 Pro (depending on the music type and your personal preference in the positioning of the vocal).
Stock = 7.0(B-), 49860 = 6.8(C+/B-). 7.5(B)
 
 
Final thoughts:
It's lacking that kind of full and warm sound which I prefer. Keep in mind that all scores and impressions are directly related to the Beyerdynamic DT 990 Pro used in this review. I'm surprised by the amount of changes that op amps can actually do to alter my perceived sonic experience, so it's not entirely psychological after all. If I was asked to give an analogy about my listening experience of LME49860, I'd say it's like drinking a glass of water. It's oderless and its taste doesn't linger. I wouldn't recommend 49860 for less dynamic sounding headphones. The LME49860 is a step in the right direction from stock. I enjoy the new SS and the overall improvement in SQ with great transparency. It's easy to listen to and I no longer feel ear fatigue even after prolonged listening for several hours. I like the fact that I can enjoy listening all day with my comfy DT 990 Pro

 

[cheuh]

I am interested in pairing the Sennheiser HD600 with the Asus Xonar STX. From my understanding, the STX  would be able to drive them, but not to their full potential. What benefits would I hear (if any at all) if I paired it with an external AMP around the same price range such as the Schiit Magni or Fiio E09K?

 

[bcschmerker4]

Quote:

Ok, so I figured I got nothing to lose by ordering 3 free samples of LME49860NA/NOPB from TI. Order was processed and sent on the same day, and next day delivery ETA from MN, US to BC, Canada, I'm impressed!

Just hope I don't get hit by customs, etc, but even then it's still fair bit cheaper than ordering them from a distributor. Either way, I think this is a step in the right direction. It's definitely an upgrade from stock op amps.

Congratulations on proofing the National Semiconductor®/Texas Instruments® LME49860NA's at the I-V.

I'll be checking eBay® for appropriate adapter PCB's to fully tune the same vendor's LME49990MA (which appears to be a direct descendant of the LM318AN high-performance op amp from the equivalent schematic) as a package with surface-mounted compensation filters for the line-level buffer - I have both a Hewlett-Packard® HP2009m display with internal speakers and a Pyle® PCA2 offboard 40Wx2 amplifier for bookshelf speakers that my STX can drive via the dual-RCA output jacks.
 
Anyone done an A/B test of dual Texas Instruments® THS4031's vs. single Texas Instruments® THS4032 for any one of the three dual-op-amp positions on an Essence™?