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Old 31st January 2013, 07:08 PM   #141
Corvus5 is offline Corvus5  Poland
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The shipping cost to Poland from DigiKey is $60. That's too much. The price of the oscillator is $26 and I can accept it. There are no Crystek on ebay. It will be hard to find it.

I had problems removing these caps. I removed digital decoupling cap. One leg stands out, one came out parially like on some of your pictures. I can't solder anything there even with soldering flux. That's why I'm trying to find most fine solution and remove these FG when I'm pretty sure what will be put there.

This oscon was hot before I added there 2x1000uF. It's still not much hot, it's just not cold.

I may try to put my external PSU (half-wave, +11.5V/GND/-11.5V on LM317 and LM337) on the +12/GND molex line and leave 5V/GND to the old PSU. Similar to the idea you came to. Which power planes on the Xonar will it change?
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Old 31st January 2013, 08:57 PM   #142
Corvus5 is offline Corvus5  Poland
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I added 2x47uF KZ to these 12v filtering caps. I'm a little tired and I didn't hear any clear difference which is something new ;-) After some time I checked temperatures and all caps (5v filtering and 12v filtering) were cold.
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Old 31st January 2013, 09:19 PM   #143
Coris is offline Coris  Norway
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Quote:
Originally Posted by Corvus5 View Post
The shipping cost to Poland from DigiKey is $60. That's too much. The price of the oscillator is $26 and I can accept it. There are no Crystek on ebay. It will be hard to find it.

I had problems removing these caps. I removed digital decoupling cap. One leg stands out, one came out parially like on some of your pictures. I can't solder anything there even with soldering flux. That's why I'm trying to find most fine solution and remove these FG when I'm pretty sure what will be put there.

This oscon was hot before I added there 2x1000uF. It's still not much hot, it's just not cold.

I may try to put my external PSU (half-wave, +11.5V/GND/-11.5V on LM317 and LM337) on the +12/GND molex line and leave 5V/GND to the old PSU. Similar to the idea you came to. Which power planes on the Xonar will it change?
OK! Hot is something, a little bit warm is a little bit different...

To remove the caps: just move it back and forth (is not very big movement in the beginning). It will take a little time, but this movement will broke their legs at last. If you can not solder right in that point (broken leg), then you can scratch a little bit the isolated surface around that rest of the cap terminal. So it will be fine at last...
When use another external PSUs (board on bench) for measurements or another tests, you have to start in the same time both PSUs (12v/5v). Is quite easy to fix this...
Is right that is quite expensive the shipment at Digikey... Maybe you have Farnell in Poland... Maybe they have the same...
I did not get it your question about the changing of Xonar planes...
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Old 1st February 2013, 04:25 PM   #144
Corvus5 is offline Corvus5  Poland
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I mean which voltages will change if I replace +12V on molex.
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Old 1st February 2013, 06:46 PM   #145
Corvus5 is offline Corvus5  Poland
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I removed FG caps for the TPA using slightly diffent technique. It's somewhat clearer, higher tones are louder, some little distortions are being heard in the sound. For my ear the frequency response in higher tones is now more flat in the 10k-20kHz range.

Current setup:
12V filtering: 2x1000uF Elna RJH
5V filtering: 1000uF Elna Silmic II
DAC 5V: 2x47uF Os-con SC or 4x220uF Elna Silmic II
DAC internal filtering: no change
3.3V: (removed FG cap) 2x47uF Os-con SC + 1uF ceramic
some caps near the 12V regulator: don't know what are they for, no change
I/V opamps LM6172: 2x100uF Nichicon Muse KZ, rail-rail 2x47uF Nichicon Muse KZ (one on each opamp solfer to the opamp pins)
near RCA opamp socket: not used, added 4x47uF Nichicon Muse KZ
headphone amp TPA: (removed FG caps) 2x100uF Nichicon Muse KZ

I find the LM6172 to be very, very detailed opamp. If I improve sound for the LM6172, the sound will improve on most of other opamps. What about suggested input resistors for these opamps? I heard some tweaks may be needed for them to fuction properly lub fixing input bias.
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Old 2nd February 2013, 07:03 AM   #146
Coris is offline Coris  Norway
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Quote:
Originally Posted by Corvus5 View Post
I mean which voltages will change if I replace +12V on molex.
+12v on Molex power a quite big area of the entire board. The clue here is to let the power coming in to Molex as it as. One may cut only the power input in to the final amps, and feed those from an dedicated/clean +/- PSU. It may also cut it the -12v for the final analogue stage, which is made it on the board (little switching PSU on Xonar).
The rest of the +12v coming from Molex it may be also used to create (cascaded regulators) an local 3,3v PSU for the digital stage on the board. The same 12v from Molex have to be used to synchronize the board Power ON sequence with the Power ON of the computer. One may not remove this 12v rail from Molex and change it with an different PSU. This is quite important to prevent bad functioning, errors, and maybe damages on the board/computer.

If you modify the 12v on Molex input (anyway the Power ON sequence of this rails it have to be the same as for the rest of the computer), then it will be affected the entire board functioning. This is not a very good idea. If you isolate the power rails of the final amps from the rest of the power system on the sound board, then you can modify as you wish this tensions values (accordingly to the opams data sheet), to find the best results. The GND of the entire power system it have to be common, and with very short connections.

To be honest, I have to say that I`m enough critic to how it looks your board with all that quite big caps soldered everywhere. Is not about the aesthetically point of view, but about the functioning consequences...
How is done your mods in this area, it may introduce oscillations, high ESI values, and the caps quite big areas can capture/induce all sort of electrical parasitics from the rest of the computer.
One may not forget that digital circuitry are very noisy. Spikes and high frequencies noises are everywhere around those circuits. The digital system is not affected to much of such, because strong filtering of all sorts it is happen in the digital signals paths. But eventual sensitive analogue circuits placed near to digital stages it may be quite strong affected of such intense electrical activities. The noises is very hard to be removed from analogue stages without strong perturbations on the useful signals. That because one may care much to shield accordingly such analogue signal processing stages.
The original shielding of the STX/ST board it may be in its place. That is a not very well shielding (aluminium), but anyway is better than nothing. You may find a solution to have the better caps in right places, and in the same time care for an good shielding, specially for the analogue stages on the board.

Yes, I/V stage is quite important to get the right sound. Here is enough to work to find the best. On both I/V converter resistor and the feedback caps. If you read carefully the LM6172 data sheet, you may find that setup which can lead you to the best sound. When you experiment with this I/V stage, is better for appreciations to let in place that opams which are there for the moment. After you are satisfied with the result of tweaking I/V stage, then you may go further end experiment with another final opamps. Then back to I/V stage for another tweaks details ... and so on, back and forth until you find the best setup. It is quite much time consuming this kind of mod, but it brings the best results... After you set up the analogue stages, you may want to put in place a better oscillator. That will be the final improvement.

Last edited by Coris; 2nd February 2013 at 07:16 AM.
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Old 2nd February 2013, 04:01 PM   #147
Corvus5 is offline Corvus5  Poland
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I remove more FG caps. The sound signature can change so much when playing with 5V that is hard to find the sweet spot.

It's odd the shipping here is $60 (free from $200) while to the Germany it's $30 (free from $100).
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Old 2nd February 2013, 05:27 PM   #148
Corvus5 is offline Corvus5  Poland
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I'm trying to figure out how the power on the xonar works. Below is my first sketch. Are the regulator filtering caps before and after the chip? Does the -11V inverter use 12V or 5V voltage? Is there additional regulator for -11V and filtering on the card?
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Old 2nd February 2013, 08:08 PM   #149
Coris is offline Coris  Norway
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Your schematics is quite right...
I`m not very sure now (is quite long time ago I have been in this project), if the -11v or -12v is created from +12v or +5v. I think it is used +12v. You may go back in this thread to find those informations. I`m sure that I have wrote about this subject in the beginning of the thread...
There is an regulator, 7912 which it were designed to regulate the -11v from inverter... Just stupid, but is like this on the board... You have to cut the output of that regulator to isolate the - rail for opams. The +/- rails goes to headphone chip too. You may read the description of this power supply mod in the beginning of the thread or so. There are som important informations about this in earlier posts (mine and others).
The 3,3v rail feed too the main processor and the chips for SPDIF in/out. There is an quite important current on this 3,3v rail for digital stage on the board (few hundred mA).
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Old 2nd February 2013, 09:38 PM   #150
Corvus5 is offline Corvus5  Poland
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I often return to the beginning of the thread. I searched for the 7912 on the card but didn't it find it. I'll try tomorrow.

I returned back to the only 1 oscon on the 3.3V decoupling. Sound became soft. It's not transparent, but soft and pleasant. Everything sounds fine, reminds me of tube amp. However I prefer more transparent and clear sound.

Will the regulator work fine with the output pin cut? I mean can the leg be in space not connected to anything while the other leg is connected?
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