Well, I was looking something with pure solid state now, and found that alternative.
Btw, I can do my own installs w/o any problem, I'm good with soldering. The only problem with those mods from photo, is the card got too thick and I wonder how it will fit inside the case.
Here it is, I put the V+ from 7805 through a coil of unknown value, the cap is WIMA MKP 0.26uf, shortest paths to gnd and clk are ensured by sticking using epoxy to AV100 processor (dissipation 0.15W as per datasheet so I won't have to worry about heat). Clk is fed through 47R to the point marked in the pic in previous pages. Measurements are about the same but it sounds great
By coil you mean inductor?
Color is blue, grey and gold (correct?).
If so, then the value is 68µH with 5% of tolerance.
The mod is designed to fit two standard computer slots space (without transformers, which are to be place it somehow beside in the PC enclosure).
Well, there is required a little bit of space to implement this mod.
The biggest challenge when implementing my mod is to solder in place the 0,65 mm pitch connector over the original DAC chip, so to have a good electrical connection and as a good mechanical assembly.
The DAC module (4 layers board design) it include a first regulators stage (TPS), then ADM7151 as the second regulation stage for each of the DAC chip power rails (Vdd/Vcc). Digital interface totally isolated from the rest of the computer, as the completely separated GNDs.
The post DAC signal processing (4 layers board design) is highly customizable, and it can provide simultaneous balanced and unbalanced outputs, as only one of these. It use a fully differential approach for balanced out, and any it can use any wanted opamp for final buffer (OPA, Muses, LM, etc.) The user can chose to add filtering of the analogue signal (between I/V and final buffer) or not. Four TPS adjustable regulators are included for both +/- rails,and independent for I/V and final buffer stages.
The power supply of the kit it include Schottky rectifying bridges, and it provide power for all the system, including for charging circuit of the clock board battery. Relays are used to synchronize power up sequence with computer.
The system it use two small toroid transformers (15v and 6-7v AC).
The battery powered clock board it have 4 different available oscillators footprints, which it can be populated, connected and disconnected as one may want (for experimenting reasons), and it provide a very clean clock signal for all the versions of ST/STX boards. Vibrations damping mechanical system for the entire clock board is also included.
This modular DAC system (equipped with PCM 1792 or 1794) it can be used as stand alone DAC too. One may only provide to it the I2S data, coming from any kind of digital source.
One can see here the implementation of the mod kit in a prototype approach. Pictures of the kit in its final version it will be published soon.
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As I can see, it consumes 3 slots. You always count the card itself too.
Looks good, but I would have problem to continue to use my Bursons, as they are kinda big too.
Edit: I would be forced to use something like this (10cm, 20cm and 30cm cables included):
http://www.amazon.com/Bplus-KZ-B21-...F8&qid=1421033074&sr=8-14&keywords=pcie+riser
Cheaper version, but I don't know about the quality:
http://www.ebay.com/itm/1-SET-Flexi...707?pt=LH_DefaultDomain_0&hash=item3a8750fbf3
Looks good, but I would have problem to continue to use my Bursons, as they are kinda big too.
Edit: I would be forced to use something like this (10cm, 20cm and 30cm cables included):
http://www.amazon.com/Bplus-KZ-B21-...F8&qid=1421033074&sr=8-14&keywords=pcie+riser
Cheaper version, but I don't know about the quality:
http://www.ebay.com/itm/1-SET-Flexi...707?pt=LH_DefaultDomain_0&hash=item3a8750fbf3
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No any reason to use Bursons in connection with this mod... This is something else, a different and superior approach, and no need any Bursons or something similar.
It looks like it take 3 slots, but it is not the final version... However, a modified sound card need its space inside the computer.
It looks like it take 3 slots, but it is not the final version... However, a modified sound card need its space inside the computer.
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That's right, since then I also added an axial tantalum 22uf/16V to the clock supply and everything changed for the better.
My final version of the mod on ST/STX boards (assembled).
Post DAC analogue signal processing it can output simultaneous balanced and unbalanced. In this case pictured here, the board is populated only for balanced output (using headphone connectors). DC coupled outputs. The Asus original sound card is also fully functional, on both ADC and DAC stages, so as it was designed, in parallel with the add on boards/DAD system.
Next step is to mount this mod/kit on a STX II edition board.
How it sounds? I can only say that I can not notice any difference between this PCM1792 DAC system and a ES9018 one...
Post DAC analogue signal processing it can output simultaneous balanced and unbalanced. In this case pictured here, the board is populated only for balanced output (using headphone connectors). DC coupled outputs. The Asus original sound card is also fully functional, on both ADC and DAC stages, so as it was designed, in parallel with the add on boards/DAD system.
Next step is to mount this mod/kit on a STX II edition board.
How it sounds? I can only say that I can not notice any difference between this PCM1792 DAC system and a ES9018 one...
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So basically you remove the clocks return path and hope this will improve things, for signal integrity the clock and its ground should be at least twisted pair and enter the board next to each other... The signal lengths, rubbish decoupling and splitting the clock signal from its return paths make it pointless putting that clock mod on...
For those of you who have added an external linear power supply to your ST or STX sound card via the molex connector - Does it matter if the PC is powered up after the external supply to the molex is on? Can damage be done by bad sequencing of the power supplies? Advice would be appreciated so I don't make smoke.
IMHO adding external power supply to the molex won't make much an improvement. There's switching regs ICs on the board that provide +/- 12V for the IV and headphone amps from +5V on the molex and they're noisy. Also the 5V analog for the DAC is powered from +12V of the molex through a 7805 - here you will get SOME improvement. 3.3V comes directly from the PCIex slot and it's... dirty.
The best results would be to add linear regulated power on the board with separate feeds to +12,-12, 5 and 3.3V.
If you really feel the need to add external power to the molex I'd say 2.5/3A for the 5V line and 0.5/1A for the 12V line.
I've connected the molex many times AFTER the rest of the PC was on and I think you will have no problems powering the molex first as long as the external supply is grounded to the PC supply (even at the molex connector).
In short you will make no smoke around if the supplies share the same ground.
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7805 feeds 5V analog supply for the DAC chip. To lower jitter you might install a new clock system (TCXO), as I did. Did you try optical as it will isolate the grounds of the PC and the external DAC/receiver? I see no reason for external supply if you use SPDIF out, 3.3V is used for the chips on the digital side and it's drawn directly from the PCIex slot.
I tried the optical using a glass toslink cable. It was so-so. Then I added a transformer to the rca output to isolate the coax spdif. Better.
I thought the clock was powered from the 12v on the molex and the 7805 regulator. Not so? I put a ferrite core around the 12v on the molex and it seemed better yet. But maybe I just wanted it to be better. Will try that one with and without again.
Thanks again lucpes
Hugh
I thought the clock was powered from the 12v on the molex and the 7805 regulator. Not so? I put a ferrite core around the 12v on the molex and it seemed better yet. But maybe I just wanted it to be better. Will try that one with and without again.
Thanks again lucpes
Hugh
On the back of the board near the PCIex connector is the 3.3V filtering. If I'm not mistaking there's a ferrite bead and a capacitor for the STX II and two caps and a ferrite for the old STX.
I added a MKT capacitor of 100nf 5mm pitch (bended legs to fit) on one of these caps on my STX and it changed the whole sound tonality of the card (better highs, starts to sound like my Audio GD DAC). You might try and see if you like it. I was surprised, I have a Seasonic 750W PSU which is supposed to be among the best supplies when it comes to ripple.
Someone on this thread replaced the ferrite with an inductor and added an 22uf ceramic on that location and reported better sound.
I added a MKT capacitor of 100nf 5mm pitch (bended legs to fit) on one of these caps on my STX and it changed the whole sound tonality of the card (better highs, starts to sound like my Audio GD DAC). You might try and see if you like it. I was surprised, I have a Seasonic 750W PSU which is supposed to be among the best supplies when it comes to ripple.
Someone on this thread replaced the ferrite with an inductor and added an 22uf ceramic on that location and reported better sound.
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