Xonar ST/STX mods... - Page 13 - diyAudio
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Old 26th January 2013, 08:54 AM   #121
Coris is offline Coris  Norway
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I forgot to answer you to a previous question about the Xonar driver I use.
I have tried Unixonar. I found out that it had some issues (for me) in the way it were put together, and the sound it were not specially improved because the mods done on the original driver.
I found out my self that to modify the original driver, update some part of it and so on, is not very difficult. So, I installed the last original one, I`ve done my self the necessary mods (ASIO update, and few other) and I run the original one.
I noticed that is quite important for the sound and sound stage out of the STX/ST how is made and function the motherboard and/or the processor, and maybe the clock system in the computer. I can not say exactly what it may be in this case, but I`ve only noticed differences in sound quality (especially changes in sound stage) when used one or another motherboard/processor with the same sound card.
I recommend to install and control the windows timer resolution (by the application with the same name). This have in my opinion an quite big impact in the way the data is streamed in the system, and in this sound board case too.
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Old 26th January 2013, 10:49 AM   #122
back is offline back  Greece
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guys i was wondering about all these mods for external psu for the card.what about if somebody makes two serial psu one with 5v and one with 12v volt and feed them to the molex connector (i read somewhere that 5v must be high current maybe 2A)without cuting any traces to the soundcard.wouldn`t this be a much easier improvement?do you see any problem to this?
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Old 26th January 2013, 05:13 PM   #123
Coris is offline Coris  Norway
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The point with those external PSUs is to power the board components/stages in a right way. Specially the analogue stage of the board which need +/- power. Minus part for the analogue is supplied on original board by an oscillator which use the +12 rail to do this. More than this , the final opamps need an +/-15v to give all of its. The original regulator on the board is 7812, which it will regulate what is coming from 12v rail... What kind of regulation is that? Not enough, the power which is to be measured on the analogue stage is +12v (more or less) and -11,5 (more or less)... They who designed this board did not care about output offset. They used AC coupling to prevent offset issues...
The board have many design faults and that because one may need to do it right to get the most of that this card really can... A part of this "doing right" is using good/clean analogue PSUs for the opamps...
This is the story of mods for this sound card...
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Old 26th January 2013, 06:38 PM   #124
back is offline back  Greece
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Quote:
Originally Posted by Coris View Post
The point with those external PSUs is to power the board components/stages in a right way. Specially the analogue stage of the board which need +/- power. Minus part for the analogue is supplied on original board by an oscillator which use the +12 rail to do this. More than this , the final opamps need an +/-15v to give all of its. The original regulator on the board is 7812, which it will regulate what is coming from 12v rail... What kind of regulation is that? Not enough, the power which is to be measured on the analogue stage is +12v (more or less) and -11,5 (more or less)... They who designed this board did not care about output offset. They used AC coupling to prevent offset issues...
The board have many design faults and that because one may need to do it right to get the most of that this card really can... A part of this "doing right" is using good/clean analogue PSUs for the opamps...
This is the story of mods for this sound card...
you are right i never thought iy`s +-12 so i feed very clean power at the molex the oscilator will somehow spoil it.i guess it`s better to power the opamps directly.do you know what the 5v is powering also?
i see at your photos that 3.3v is supplied from pcie so what is molex 5v for?

Last edited by back; 26th January 2013 at 07:01 PM.
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Old 27th January 2013, 06:41 AM   #125
Coris is offline Coris  Norway
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Quote:
Originally Posted by back View Post
you are right i never thought iy`s +-12 so i feed very clean power at the molex the oscilator will somehow spoil it.i guess it`s better to power the opamps directly.do you know what the 5v is powering also?
i see at your photos that 3.3v is supplied from pcie so what is molex 5v for?
5v it feed some control circuits, control of the relays, and so... There is a circuitry on the board which give informations to the main processor that the board is powered on as it should, and this is managed by the driver software. That because the Molex it have to be intact and connected in place. Else errors messages pop up on the screen and no sound... Eventual modifications it have to be made on the power traces on the board, taking care that only the targeted chips have to be powered from an eventual external PSU. The external PSU is in fact dedicated to the +/- rails for the output analogue stage (I/V and final opamps), but part of this power is used too for the digital in stage of the board. The rest of the power system it have to be in function as it were designed. I have removed completely the headphone stage from my board, as I never needed such. So that chip did not take any power from the rest of the system. Is important that even though some relays may be not used, their connections to the control power have to be intact (they have to be clicking to give the messages to the main processor that all it still be OK in the system).
Is now quite long time I`ve been involved in this project. To give very precise answers now, it mean I have to go back to may papers (find those...) and do researches... But the most of the informations are wrote down on the thread.
So, please read carefully my posts from the beginning of this thread to get more details.

I have used from Molex only 12v rail, to make 5v for the analogue stage of the DAC and clock, and 3,3v for the rest, using cascaded regulators. 5v for the relays it still come from the Molex/computer rail. Details are in the previous posts.

Last edited by Coris; 27th January 2013 at 06:52 AM.
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Old 27th January 2013, 08:26 AM   #126
back is offline back  Greece
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it seems you have done some serious tracing here.i have some salas very high quality psu`s.i guess if i cut some regulators and feed them there then i will be ok.no need to cut traces.unless i missed something at your photos.
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Old 27th January 2013, 12:00 PM   #127
Coris is offline Coris  Norway
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you need to cut traces to isolate the original regulators on the board... But you can of course cut the output terminal of the old regulators. You may chose what is more convenient for you.
Is better let the regulators on the board, than desoldering it. The board is very destroyable when desoldering components from it.
Care about where is to solder the GND of the new PSU. Chose very short connection in the the near area of the opamps, no mater the side of the board.
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Old 29th January 2013, 08:41 AM   #128
Corvus5 is offline Corvus5  Poland
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I played more with the card. To the existing caps I added monolithic ceramic to the digital stage, headphone amp and 5V decoupling. There were still some inconsistencies in higher tones, but better than the time I was using only opamp sockets.

Then I tried the 5V filtering. Coris mentioned there are 2 of them. I don't know the connection, maybe they are in parallel. Due to existing caps I could only access one of them. There are 2x100uF. I added one 470uF Nichicon HV which is quite slow and sounded breathless in the opamp stage. This filtering changed almost every aspect of the sound in every stage and is quite global like 12V power decoupling.

There may be an error for the blue text: 12v power filtering.
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Old 29th January 2013, 12:54 PM   #129
Coris is offline Coris  Norway
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You may not expect that only decoupling caps or filtering is enough to improve the whole sound out of this card.
I will suggest that you do what do you consider to be done about those filtering/decoupling caps (you may even not notice a clear/dramatic improvement in the sound), and then just go further to another mods, which it may be necessary to get more improvements.
Those caps are only a part of the mods to be done for to notice a dramatic improvement of the sound... You can go back to this stage maybe after the rest of the mods are in place. Then you may notice better the differences when one or another caps are in the right place.
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Old 29th January 2013, 03:03 PM   #130
Corvus5 is offline Corvus5  Poland
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What are the other mods? There is mainly quartz to change and what else? Play with the feedbacks.

What I read in the this thread is that the 5V after 7805 is used to make +12 and -12V and then regulators like 7812 or similar. If so, then why the card uses molex 12V and 5V to power the card? The power drain from both lines are similar as mentioned in the thread. So maybe the +12V goes to the +12V regulator, +5V to the +5V, and then -12V is made from one of them? I'm just curious to know which filtering changes what.
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