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In Reply to: RE: Thanks posted by jackwong96 on November 21, 2011 at 08:52:54
Comes from the AK4114 in this case. Envy 1724 also has I2S output (sorry, I don't have a link for the datasheet, not sure it's available openly on the net, but if you send me an email I can send it).My notes from my original Juli@ follies on the sources of the I2S lines are as follows:
J3 Pin 1 -> 1724 PSDOUT[0] ( I2S data out) -> AK4358 SDTI1 (I2S data in)
J3 Pin 5 -> 1724 PSYNC ( I2S Word Clock ) -> AK4358 LRCK (I2S Left/Right Word clock)
J3 Pin 7 -> 1724 PBCLK ( I2S bit clock out ) -> AK4358 BICK ( I2S bit clock in )
J3 Pin 9 - > Xilinx on the digital board -> AK4358 MCLK ( I2S Master Clock in )
J3 Pin 11 - > Xilinx & AK4114 on the digital board - > AK4358 PCN (Reset)
I suspect the AK4114 provides I2S from a SPDIF input to the 1724 which then passes it onto the AK4358 DAC. But as I'm killing the SPDIF input for my purposes, I'm hoping that doesn't matter.
That doesn't mean that the AK4114 doesn't provide the I2S to the Envy 1724, but with the clocks directly connected to the 1724, I suspect it is the one that provides the I2S.
But I2S out still may not work without the AK4114 available. We'll see!
On the caps, I hope to try Oscons there a little later in the week UNLESS the ceramics mellow out a bit more. I'll let you know on that too. Still, even with the ceramics, the sonics are quite nice... just not as sweet in the highs as I'd like under all conditions.
And thanks on the GA-H55M-UD2H chip removal info. See my questions about the Q67-based board in another thread... maybe the last native PCI option?
Thanks again!
Greg in Mississippi
Everything matters!
Edits: 11/21/11Follow Ups:
I tried un-powering the AK4114 digital audio interface chip on the Juli@ last weekend by lifting the power pins. After this was done, that Juli@ no longer functioned correctly. It caused a requested resource error.
I guess it doesn't matter where the I2S originates... Juli@ needs the AK4114.
OTOH, the rest of the findings last weekend were VERY positive. Will post an update later this weekend.
Greg in Mississippi
Everything matters!
Can I find a PCI card similar but better than Juila@?
Or even if there is one... especially if you are willing to modify the card.
My opinion... Few if any sound cards are designed to provide a high-quality SPDIF & I2S feed for use in a dedicated, high-end, tweaky music like ours. The Juli@ uses older, but still good chips. No other card I know of provides such easy access to the I2S feeds and removal of 90% of the stuff we don't need by just lifting off the analog portion. And it takes well to modification... and is inexpensive enough to do so with impunity.
I'm interested in hearing of alternatives. But I think that most of the development today is around USB-connected interfaces... and the EXAU21, the Luckit.biz XMOS-based unit, and the upcoming Twisted Pear unit are the best bets at this time in this realm... but it will change at time marches.
Greg in Mississippi
P.S. Listening to the Juli@ digital section with mostly Oscon additional filtering caps instead of large-value ceramics. Interesting contrast... Both are good and each has it's strong points. I'm going to delay my next report a few days to give this card (it was unused) and it's mods time to break in a bit and also swap back in the ceramic-bypassed card with a couple of tweaks to try and reduce it's negatives while keeping it's strong points. Couple of teaser photos attached...
Everything matters!
Jack,
So I've run the Juli@ digital card with the additional ceramic cap bypasses in for a couple of weeks... and while it's improved, I'm still not thrilled by it. There's a bit of 'confusion' to it and a very slight sense of 'harshness' in the highs on some recordings.
Very curious about this as these are all deep-digital processing chips... the controlling CPU, the PCI/Audio controller, and some helper chips. Looking at a lot of the commercial, even high-end commercial DACs & digital playback units (SACD/DVD/CD/SD players, etc.) out there, they generally had some number of ceramic caps as PS bypasses. And the Juli@ already has all of those ceramic 'BCxxx' caps.
Darned... it makes a LOT of sense to me to use very low-inductance caps mounted in a way to keep that inductance low around these deep-digital processing chips. And the ceramics seemed to fit the bill AND be the industry standard.
So my next experiment will be to do another Juli@ digital that's identical to this one except these bypasses will use some small Oscons... I have some 33uf/16v that will work well here and are small enough to fit without a lot of hassle.
Continuing my research, I went looking for situations where people used caps other than ceramics for digital chip bypasses... and found these:
http://www.diyaudio.com/forums/digital-source/186245-dac-2496-ak4393-dac-kit-cs8416-ak4393-5532-a-5.html#post2622112 ("PPS film (again if you can get them) bypassing on the digital electrolytic's and those massive power filter caps")
http://www.diyaudio.com/forums/digital-source/142562-microsd-memory-card-transport-project-post2594576.html?highlight=pps+capacitor#post2594576 (for putting non-SMD PPS caps on the regulator outputs on their SD Card Player)
http://www.diyaudio.com/forums/digital-line-level/79452-building-ultimate-nos-dac-using-tda1541a-81.html (he also has some interesting regulators that filter both the rail and the ground... very curious about these!)
And looking closer at the AckoDAC & the RAKKDAC, I now suspect they both also use some SMD poly caps around their digital circuits, at least on the digital side of the DAC.
Of course, a number of them also use some tantalum caps there too (as does the Jul@ around the AK4114 digital input-output transceiver and the ADC & DAC & output stages on the analog card). I'm not ready to go there yet, but I don't have a problem with PPS SMD caps.
Now I'll also take the one with the ceramics, pull them off, and put on 1uf PPS caps (which I just happen to have a small supply of here).
I also found some people who swear by using BG NX caps as local bypasses, at least around DACs. I agree that's a good bet, but most people won't be able to duplicate that and I'm trying to come up with mods that can be duplicated with easily-available components, so I'm not planning to try my limited supply of those no-unobtainable caps on my Juli@ digital section.
I still owe some replies on this thread to Uncle Leon on his latest capacitor work and to fork. I hope to get to them this week.
Later!
Greg in Mississippi
P.S. Another interesting poly cap trick is discussed in this thread: http://www.diyaudio.com/forums/digital-line-level/196474-ess9018-try-new-try-more-3.html where Bunpei replaces the exotic TP shunt regulators for the Buffalo-II's AVCC with simpler & more pedestrian LT1763s (Actually a Toshiba TAR5SB which is a near equivalent) & a 100uf/800 polyprop cap from CDE on the output & likes it a LOT in comparison!
Everything matters!
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