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The Xonar Essence STX Q/A, tweaking, impressions thread - Page 291

post #4351 of 4875
Quote:
Originally Posted by germanium View Post

By the way the LME49990 spec sheet calls for at least double power supply bypasses. The STX does not have the recommended bypasses stock so may not sound as intended if mounted to the STX & as such may actually have some emphasis in the bass as a result of less well delineated high frequencies compared to if the proper bypassed were present on the STX card 

 

That may be so in theory, but it's not how it works out in reality, LME49990 sounds audibly cleaner in all frequencies ie higher resolution of detail, easier to detect tiny tiny details, room placement of instruments, reverberation, no irritating s-sound sibilance etc etc stock sounds really dry, flat and boring in comparison. It is possible the LME49990 would sound even better with proper power supply arrangements but it is superior to stock even when the implementation is half-broken  :-)

 

I would be very happy to be pointed in the right direction on how to enhance the power supply on the ST/STX, a step-by-step guide would be amazing, is it doable without having an oscilloscope etc? 

post #4352 of 4875
Quote:
Originally Posted by xeizo View Post

 

That may be so in theory, but it's not how it works out in reality, LME49990 sounds audibly cleaner in all frequencies ie higher resolution of detail, easier to detect tiny tiny details, room placement of instruments, reverberation, no irritating s-sound sibilance etc etc stock sounds really dry, flat and boring in comparison. It is possible the LME49990 would sound even better with proper power supply arrangements but it is superior to stock even when the implementation is half-broken  :-)

 

I would be very happy to be pointed in the right direction on how to enhance the power supply on the ST/STX, a step-by-step guide would be amazing, is it doable without having an oscilloscope etc? 

I never said that it wouldn't still be better than stock, just not as it should be. My experimentation with power supply bypasses has yielded huge fruit even with stock opamps so I can imagine what it could do for the LME49990.

 

Yes it is extremely doable on this card & does everything I had hoped for sonically, even with stock opamps.


Edited by germanium - 5/16/13 at 1:49am
post #4353 of 4875

I Really need to get another 49990 for the buffer output and try the analog out to my AVR.

post #4354 of 4875
Quote:
Originally Posted by nicholars View Post

Well the IEM's I have currently are the Sennheiser IE8 (16 ohm Sensitivity:125 dB) and Shure SE215 (20 ohm Sensitivity (1 kHz): 107 dB SPL/mW)

 

I know it should be 8-10x the impedance of the output jack but I cannot find any sound cards (non professional) with a low impedance (1-3ohm) .... I guess the STX should be pretty good and an improvement on my NAD 326Bee (68 ohm) jack though? Would be better to have a 1-2ohm headphone amp I am sure but I would like a soundcard with RCA and SPDIF out as well as headphone amplifier...

 

Would be good if someone who has used the Xonar ST/STX with IEM's or IE8/SE215 could tell me if it the headphone amp with IEM's is decent enough to last me until I can get an external amplifier.

 

Hmmm well thanks for the help everyone... I guess I will have to blindly buy one and just hope it works then...

post #4355 of 4875
Quote:
Originally Posted by nicholars View Post

 

Hmmm well thanks for the help everyone... I guess I will have to blindly buy one and just hope it works then...

 

If you're deadbeat on IEM:s I guess the ODAC/O2-combo would be a significantly better choice thanks to lower output impedance, and an overall sound design. More expensive, but it may be worth it in your case.

 

edit. personally I hate IEM:s because I find it too difficult to make them fit good enough to give an even bass-response, I just use them on the sub and alike.


Edited by xeizo - 5/16/13 at 6:26am
post #4356 of 4875
Quote:
Originally Posted by xeizo View Post

 

If you're deadbeat on IEM:s I guess the ODAC/O2-combo would be a significantly better choice thanks to lower output impedance, and an overall sound design. More expensive, but it may be worth it in your case.

 

edit. personally I hate IEM:s because I find it too difficult to make them fit good enough to give an even bass-response, I just use them on the sub and alike.

 

I prefer over ear as well but at the moment I don't have any money and I have 2 pairs of nice IEM's so I need something to use those with until I can afford some hifiman HE-400. Problem is I cannot afford much more than the STX and I also want the RCA and SPDIF outs because it will be replacing my Xonar D2. Quite suprised that noone uses IEM's from the STX!

post #4357 of 4875
Quote:
Originally Posted by xeizo View Post

 

That may be so in theory, but it's not how it works out in reality, LME49990 sounds audibly cleaner in all frequencies ie higher resolution of detail, easier to detect tiny tiny details, room placement of instruments, reverberation, no irritating s-sound sibilance etc etc stock sounds really dry, flat and boring in comparison. It is possible the LME49990 would sound even better with proper power supply arrangements but it is superior to stock even when the implementation is half-broken  :-)

 

I would be very happy to be pointed in the right direction on how to enhance the power supply on the ST/STX, a step-by-step guide would be amazing, is it doable without having an oscilloscope etc? 

how does the 49990 in terms of soundstage compare to stock, and also in terms of bass. 

post #4358 of 4875

Wow not a single person has used IEM on the xonar STX

post #4359 of 4875
Quote:
Originally Posted by nicholars View Post

Wow not a single person has used IEM on the xonar STX
I tried my fxd80s on the card, didn't enjoy it.
post #4360 of 4875
Quote:
Originally Posted by germanium View Post

...By the way the LME49990 spec sheet calls for at least double power supply bypasses. The STX does not have the recommended bypasses stock so may not sound as intended if mounted to the STX & as such may actually have some emphasis in the bass as a result of less well delineated high frequencies compared to if the proper bypassed were present on the STX card 

Thanks for a detail that I should include for the adapter-PCB requirements; shoehorning in both surface-mount (Balance/Input Comp and Output Comp) and thread-through (+Vcc and -Vss supply-bypass) ceramic capacitors may very well be a necessity and should therefore be provided for from the outset to allow dual LME49990MA's to run stably in my own STX' Line-Level Buffer position. smily_headphones1.gif

post #4361 of 4875
Quote:
Originally Posted by bcschmerker4 View Post

Thanks for a detail that I should include for the adapter-PCB requirements; shoehorning in both surface-mount (Balance/Input Comp and Output Comp) and thread-through (+Vcc and -Vss supply-bypass) ceramic capacitors may very well be a necessity and should therefore be provided for from the outset to allow dual LME49990MA's to run stably in my own STX' Line-Level Buffer position. smily_headphones1.gif

On the LME49990 spec sheet as well as the normal electrolytic cap near the opamp these are bypassed by 2uf solid tantalum & .1uf ceramic caps going to ground from both + & - power supply rails. Since there is no ground connection on the SOIC to DIP adaptors one cannot incorporate the bypasses on the adaptor itself. These bypasses must be done to the STX board itself in order to have the proper ground connection

post #4362 of 4875
Quote:
Originally Posted by nicholars View Post

Wow not a single person has used IEM on the xonar STX

I had to choose between the Creative Titanium HD and the Xonar STX when I was shopping for a new card to drive my 30-40 ohm Ultrasones. The STX was said to have problems with low impedance and might end up with some mean hissing or background noise so I bought the HD instead.

On the other hand you can always use an impedance adapter/plug in between. I had to use one with my Little Dot MK V (before I switched opamps and took away its 3rd grounding wire) so that might help in case you run into trouble.

post #4363 of 4875
Quote:
Originally Posted by Radical_53 View Post

I had to choose between the Creative Titanium HD and the Xonar STX when I was shopping for a new card to drive my 30-40 ohm Ultrasones. The STX was said to have problems with low impedance and might end up with some mean hissing or background noise so I bought the HD instead.

On the other hand you can always use an impedance adapter/plug in between. I had to use one with my Little Dot MK V (before I switched opamps and took away its 3rd grounding wire) so that might help in case you run into trouble.

 

But doesn't the Titanium HD have an ouput impedance of 35ohms which is higher than the STX (10ohm)?

 

I thought the idea was that you have as low possible impedance for IEM... 8-10x the amount eg. 2ohms would be ideal for 16ohm headphones.


Edited by nicholars - 5/17/13 at 2:39am
post #4364 of 4875
Quote:
Originally Posted by nicholars View Post

 

But doesn't the Titanium HD have an ouput impedance of 35ohms which is higher than the STX?

 

I assume it is not possible to get an adaptor to LOWER impedance from the output?

Impedance adapters do work to lower output impedance but at a huge cost to output power & extra strain on the amp drive the headphone with the impedance adapter. The stress can be enough in some cases to cause the headphone amp to fail.

 

Some headphones need low output impedance while some even benefit from a higher output impedance such as the Etymotic research ER4P's. Etymotic research even provides an impedance adapter that adds close to 75ohms to the output impedance of the driving amp to convert the ER4p into the ER4s which is the more accurate model in their lineup. Most run of the mill headphones don't really even care that much what you drive them with as they have physical damping already applied to the back side of the driver. Sometime this is enough in & of itself to adequately control the driver & sometimes there is not enough for even a high damping factor amp to be able to control. This is due to damping factor losses due to the typical headphone cable impedance.

 

The highest electrical damping factor could be achieved at the driver itself without relying on the amp to damp the driver  but the driver would have to incorporate said damping into the design of the driver voice coil itself which to my knowledge no body does. That would be a shorting ring attached to the voice coil former but electrically isolated from the voice coil itself. Voice coil movement would induce a current into the shorting ring which would then act as a brake to the voice coil. This action would be strongest at driver resonance as a result of the driver wanting to move the greatest distance over a given time period happens at resonance. You may get longer movements at frequencies below resonance but the greatest distance travelled over a give time period always occurs at resonance & that is what you are trying to control. A side benefit is the shorting ring would also cancel the inductance of the voice coil at high frequencies. This would result in a flat impedance curve that would essentially take the driving amp impedance out of the picture completely. 

post #4365 of 4875

I guess I will just have to buy one and see because as you say it varies between headphones. Thanks anyway.

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