Xonar ST/STX mods...

I simulated the I/V circuit with the TINA. Before I just tested the feedback filter. Now the whole I/V is present and I plan to add the TPA circuit. I placed the output resistors too and simulated with LM6172 using ideal R and C elements. The stock bandwith is much wider.
 

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Coris, have you tried improving I/V opamp feedback? There's a resistor and maybe capacitor. I was improving this place many months ago but the card was like a stock. Now I improve this and it's amazing! The difference is much bigger than before! I can't move back. Much more details, clearer image and even proper vertical position for some sounds. Distant sounds are so clear on the opamp where it wasn't before.

Any tips? :)

Yes, I did. I actually build it my own I/V circuit and final stage. The basic tip here is use high precise and thermal stable class resistor for I/V conversion. Those resistors are quite expensive, but is about only two of such here. Good decoupling on those stages are very important too, as very short connections between DAC chip and I/V stage.
BTW, use few teens pF caps on I/V resistor.
 
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One may not be very optimistic about getting answers from Asus software team. They did not developed the original driver for years. Theirs updating schedule for ST/STX it were very poor, and so on. One may read about some efforts to improve the driver on UNi Xonar | brainbit

BTW Corvus5, how did you get into the code details of the driver software in your previous post? Did you reverse engineered the driver software? There is about an dll file which it may have those details...
 
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I do not advertise for this alternative driver. It is only information and example about how it actually works with Asus software team...

The base driver for those Xonar boards it have to be that original anyway, but the way the original driver it were written and build permit some modifications or updates quite easy. Unfortunately is not possible to be modified particular details and functions of the involved chips (registries) on those boards software.
I prefer to use only the basic driver updated by my self with the necessary files (ASIO, etc)

BTW, I have noticed that the OS structure and its audio stage (software) treatment it may play a significant role in the audio performances of the (modified or not) sound card.
I could notice in the last time better performances on my modified board when using Win8 (tweaked for audio performance with win8 Xonar basic driver).
 
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I recomend to check every driver and player software combination through LINE-OUT to LINE-IN test. With different output FPS frequency which is set by driver, player and windows combination you will have different output digital filter characteristic. This makes different sound in highest.
XMplay with unified ASIO driver is good choice in WinXP for me.

And "war" with changing OPAMPs is for laughter.
If no datasheet was available, half of people would not hear any difference :).
 
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No schematics.

I've just removed last electrolytic caps on the xonar board: Sanyo SEP 330u/16V on the 5V molex. These are mounted only on the ST board, the STX uses AFAIR 270uF oscons, series not known to me. In the datasheet SEP are good. I find other caps to better in this place. Measurements tell the same.
 
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I'm switching to the battery clock power supply today, no voltage regulator, no caps. What may I expect to hear and measure?

Good idea!
I see in the pictures that you used some standard batteries. I`m not very sure it is the right solution... It is not so much power in those kind of batteries, and it may have enough internal resistance, and maybe enough noise because that. It get discharged quite fast and what`s next? Stop playing to change the batteries?
I may use an enough high power capacity battery, as Li-Ion or so, and not at least, rechargeable. A relay it have to connect/disconnect the battery to/from oscillator, when power ON/OFF. When power off, the relay can be used to connect the charger to the battery.
A mobile phone battery is the right one to be used here. It have huge A/h capacity to power that oscillator, it decharge very slowly, and is enough small.
A such battery deliver quite long time 4,2v after fully charged. It may be enough for that 5v oscillator. But I want to use an 3,3v oscillator in that place. The processor works very well with a 3,3v oscillator... But one can also use two phone batteries serial connected (7-8v) in this case...
You may calculate (assure) the right current (data sheet) for the oscillator when powered from battery. I will recommend to simulate the current/tension needed by the oscillator using first resistors network connected to the battery. Measure and assure everything is right before connect the oscillator to the battery. Do not forget to interconnect a fuse between battery and oscillator. I have experienced an oscillator which malfunction and it shorted its regulator to GND. Using battery such malfunction can end with fire...
Use very short connection wires and ferrite bead in between on power rails. You may want to use an decoupling (100µ ceramic) cap right on the power inn pin of the oscillator.

I do not know how it may behave Vanguard when powered from battery. But another kind of oscillators (specially CMOS) I have powered this way it works wonderful on battery.

I will not tell much about the sound out of a such powered oscillator... You will have a pleasant surprise...:)
 
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Well, it is a while since this my mod project were started, done and very well working.

In the last I have changed my PC motherboard, and processor. I use now Asus Z87-Deluxe and Haswell processor. Less heat inside the enclosure, less need for ventilation, more quiet machine, and the results are just unexpected high.
I see that with some more quality improvements for the components in this mod, the whole sound system it may bring just exceptional results, never attained before for a PC based sound system.

I decided to start it again this project, but this time to realize a full profesjonal kit to be attached to the Xonar STX card. I just bought a new sound card which I will use to develop and realize this kit. I think this mod it will be exclusively destined to Xonar STX sound cards, as this type of sound card is most suitable for a high end PC based sound system. I`m of that concept that the music it have to come (natural way) from the front of the listener, so the stereo system is the most natural way to bring sound information to a subject. A sound scene it have to be developed based on stereo sources.

I plan to design an extra added PCB, which it may fit the original one, and will take a smaller place inside the computer. The kit board have to be quite easy to be attached, with points to be connected to the original sound card.
This mod will have a completely new analogue output stage, powered from a analogue PSU, and an high quality clocking system, powered from battery. Additional decoupling/filtering capacities it will be placed on this extra board too. I wish to use analogue power for whole the needed tensions on this board, but so it may be needed for an extra transformer... I will see what it may be at least the right way to be done.
I think it will be a quite expensive result, but as known, high quality results it cost a little more...
 
Hello coris I can not find the pictures on the forum.

My asus after several moddature has been shorted.

I reversed the tensions of the two linear 5v and 12v.

Now I am the 5v short. I scored 2.5 V to 3.4 A, with my peaktek 6080.

What evidence can I do, I'm in trouble.

Sorry for my Italian.
 
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Hi ciccio1112

Sorry to hear that. In this case it seems that the board it may be definitely compromised...
The only reasonable you can do, I think is to find a new sound card. Some times it happen like this and it is a part of DIY activity.

About the pictures here in the thread, I have to say that it were deleted all by mistake of an moderator for a while ago, in his try to remove some posts... This it is very regrettable. Many of these pictures are unreplaceable.
 
Hello Coris.

Thank you for your thread, I have got a lot of help.

By the way, can u check the volt of the 2 Caps located right in front of RCA output?

I have changed these 2 Caps into Nichicon Muse KZ 50v 1000 uf from the backside of PCB. And I can check "0 V" from them while the card is operating. Other Caps show me between 5 to 12V.

Well..I can hear the music with 2~3 times of "click" sound at the beginning. a while later, I get to be able to keep listening different musics without any problem.

Do you think there's some problem with "0V" of those 2 Caps?

Please let me know what show from your Caps right in front of RCA output.