|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
67.60.98.130
In Reply to: RE: cMP - the open source high-end Memory Player posted by cics on December 30, 2007 at 04:42:01
Ok, it's time to go back into an analysis and implementation of further mods to the ESI Juli@.Why? Isn't it at end-of-life with the newest motherboards either not having PCI slots or using PCI-E->PCI bridges (sure to be bad for sound quality)?
Well, I have a few Juli@'s socked away. I'm not planning to go beyond the H55 series motherboards anytime soon (and for that matter, still need to buy one of those). And I've gotten pretty good at modifying the Juli@ for better sound... And I think I can take them much farther.
Then the other question is, "Why now?". My current focus on this is driven by the availability and rave reviews of the new EXAU21 USB->I2S interface card. Available from www.exadevices.com for $430 CDN, it seems to be the SOTA device for getting I2S out of your PC. And at least two of the converts who have raved about it replaced modified Juli@'s (although more on that later). And I, of course, want to get the best sound out of my system, so to avoid having to buy an EXAU21, I want to first look at further improvements to the Juli@.
Let's start with my context. I have a very tweaked cMP with all of the standard optimizations plus I've performed the latest minimizing WinXP tweaks up through Steppe 4 and Jolida 1 & 2. My setup has 14 different high-quality linear supplies from 11 different power transformers. And I get my music out via a modified Juli@ digital section with an I2S-connected DAC roughly replacing the Juli@ analog section. Currently I use either one of two DIY cards, one AK4399-based and the other ES9022-based. Sometime later this year, I plan to FINALLY get an ES9018-based Buffalo DAC running.
First, why I2S? Because it is a parallel-clocked datastream that is directly accepted by most DACs, reducing inherent jitter and the jitter caused by the I2S->SPDIF conversion at the transport and the SPDIF->I2S at the DAC. One caution here though... I2S was always intended as a method for communicating between different chips over a short distance. My impression is that anything over 2"-3" starts degrading the signal integrity, which is why I mount my DAC cards right on the Juli@ with an I2S signal path that is generally shorter than that on the stock JulI@. Another caution is that the ES9018 DAC has in some implementations exhibited difficulties with locking onto a high-sample-rate(352 or similar) I2S signal. Luckily, there are workarounds and fixes that seem to be effective at resolving this.
Because of the need to keep the I2S lines short for best results and that you will likely be connecting to a DIY DAC (even if it's a Buffalo DAC or similar), this interface is best used by the DIY tweaker. But that is also true of the EXAU21 and of the mods to the Juli@.
A quick aside... There is an interface, patterned on PS Audio's HDMI-based standard of their latest transport and DAC, available from www.kandkaudio.com/, that enables remote I2S with likely less degradation than just extending the I2S lines longer. I haven't used this interface myself, but I do have a lot of respect for this company's work and if you need to do a remotely-located I2S connection and don't want to go the EXAU21 or other USB-connected interface, the K&K setup is said to work well with the Juli@ (they have a specially-setup interface card JUST for the Juli@. It isn't on their website, but there are posts about it on their Audio Asylum board).
Back to the EXAU21, it, as a device, has some impressive advantages over the Juli@:
1. It is a single-purpose device (USB->I2S) with a one-way signal flow, from the computer out. As such, both it's physical design/construction and it's logical firmware/driver software are simpler and likely more straightforward than the Juli@'s. And as we cMP tweakers know from the Steppe optimizations, simpler can make significant improvements in sound quality.
2. It's I2S output is galvanically isolated from the computer, strongly reducing the probability of computer-generated noise being impressed on the output datastream.
3. While it's powered from the computer's USB 5v, it can be easily setup to use a separate supply to reduce the impact of noise from the computer on its processing.
4. Because it mounts at the end of a USB cable, it has the inherent ability to bring the I2S to a remote DAC.
But there is one key attribute of the Juli@ that make it worth continued consideration... At $130-$160 new, you can get roughly three Juli@ for the price of one EXAU21. And at that price, you can afford to modify it with the comfort that a error won't wipe out almost $500 USD.So how do we help the aged (2003 or 2004-vintage) JulI@ compete with the new and greatest EXAU21? First we start with a comparison. After getting further details about the two raves on the EXAU21 improvement over modified Juli@, it was clear that the two Juli@, while both modified to a level above a stock card, were not at the same level as my current base modification. Both DID have non-motherboard 3.3v power supplied, replacing the stock LDO (Low Drop-Out) regulator which reduces the impact of computer noise on its processing. One used a shunt regulator, the other LiFePO4 batteries, both good choices. But both still used the 5v computer power from the PCI connector.
What have I done in the past that improves on this? First by providing cleaner 5v to the Juli@ digital section in addition to providing clean 3.3v. This is important as there are several devices on the Juli@ digital section that use the 5v directly instead of the 3.3v from the regulator.
Then I also do a a mod which I saw referenced on either the cPlay or cMP thread. It was originally posted by a guy named 'Marcello' here: http://forum.rightmark.org/topic.cgi?id=4:504-5 . Basically, he recommended adding a couple of local reservoir caps across the power to the main digital input/output chip (AK4114). He also recommended replacing the crystals, something I haven't done yet (my hat's off to you, Mihaylov, for having done the crystal replacement!)
My base Juli@ mod starts with:
1. Cutting the 5v power fingers on the Juli@ digital section PCI connector & feeding it with 5v from a good linear supply with a quality (Dexa) regulator
2. Replacing the 3.3v LDO regulator on the card with another quality (Dexa) regulator
3. Replace the filter caps around that regulator with larger & higher quality units
4. Put on the caps recommended by Marcello on the AK4114
This is all well and good, Back in the day, when I did all of these things along with similar mods to the analog section of the Juli@, I got HUGE improvements. It was one of the big three upgrades that I've experienced while playing with cMPs (the other two were installing hybrid/linear or fully linear supplies for the MoBo & performing the Steppe upgrades through Steppe 4). Of course, cleaning up the power to the analog side was a large part of this improvement.But now I want to take my Juli@s up a notch. So I spent some time understanding the Juli@ better, first by identifying all the active devices on the Juli@ digital section. Here's the list:
VT1721 ENVY 24 HT-S (3.3v) PCI Audio Interface... It takes the signal off the PCI buss and converts it to I2S along with other conversions and signal routing
XILINX XC9536XL (3.3v) Programmable logic chip that appears to be the main controller of how the card operates
AK4114VQ (3.3v) Digital signal interface that provides SPDIF in and out along with additional signal routing
HC125AG (5V) CMOS Buffer/Line Driver that appears to enable the switching of the SPDIF input and output signal
24LC02B SN0542 (3.3v) EEPROM 2K 256 X 8 SER EE 2.5V IND 1/2 ARAY WP - I think this is related to the control of the card, but it might be used to buffer music data
PLT133/T10 (5v) TOSLINK output
PC900V (3.3v) photocoupler SPDIF input
AV73-01L (5V) I cannot find any info on this chip, but it sits between the VT1721 & the XILINX and as such, likely plays a very key role
What to do with all this new knowledge? Looking at what devices we have there and how they relate to each other, while the separate power is good, the basic 'Marcello' mod does not really address the big power consumers/RF polluters. Also, it focuses on addressing the SPDIF, which I don't use.
The key chips that need additional power supply filters & noise suppression are the XILINX & the ENVY VT1721.
And given how I use I2S only and not SPDIF, I can just remove the AK4114, HC125AG, and PC900V as they are SPDIF-only.
Continuing to look closely at the card, the designers of the Juli@ look like they knew what they were doing (as far as I, who doesn't, can tell). There is a bypass capacitor at each power input to each device... These are the 'BCnn' chips on the back of the card. This is a good practice and provides a place to hang additional bypassing/filtering caps. Of course, the ENVY VT1721 has 12 power inputs! The XILINX is a bit more modest with only 3! But additional caps across each power input will help a good bit.
I'm looking at several options for this:
1. Large-value (100uf-1000uf) ceramic caps
2. Good digital filtering caps like Oscons
3. Good film caps, either SMD or small polypropylene.
4. Small Black Gate caps (I have enough around to do 1 or 2 cards)
Each option has its benefits and drawbacks. The Oscons would be the easiest to do, some of those bypass caps are very close to other components and it would be "very hard" to get a larger ceramic or film SMD cap mounted on top without shorts (and only just "hard" to solder in the leads from an Oscon!).
For more some more info on these options, see these threads:
http://www.diyaudio.com/forums/digital-source/190033-upgrading-modding-new-oppos-bdp-93-bdp-95-a.html
http://www.diyaudio.com/forums/pc-based/197116-xonar-st-stx-mods.html
http://www.diyaudio.com/forums/digital-line-level/196474-ess9018-try-new-try-more.html
http://www.diyaudio.com/forums/digital-line-level/151846-anybody-using-new-ess-vout-dac-es9022-4.html
http://www.diyaudio.com/forums/audio-sector/187748-pushing-limits-tda1543-nos-dac.html
Then there's the crystals. There are two, 22.5792MHz (for inputs/outputs at 44.1/88.2/176.4) and 24.576MHz (for inputs/outputs at 48/96/192). Upgrading these crystals will make a difference, but I strongly suspect that a large improvement will come just from the process of powering them separately.
Also, there's a good bit of processing happening, especially (again) at the XILINX & the ENVY VT1721 (and the AK4114 if you're using SPDIF) and it's got to be radiating a lot of RF. If you follow audio reviews, you'll have seen mention of the 'Mask of Silence' used by Arcam in their fairly recent highly-reviewed gear (the IAR suggests that the Arcam AVR600 may be the best preamp-amp combo available at the time of their review bar NONE... with a surround-sound processor just basically thrown in for free! See here: www.iar-80.com ) Reading this and other reviews of Arcam gear, both in the IAR & elsewhere, strongly suggests that this is done with a stick-on ferrite sheet... Good thing to try here (I got some from Mouser or Digikey).
So these are the additional hardware mods I plan to do on the Juli@:
1. Better power bypassing/filtering of the active components
2. Clock upgrades
3. Additional RF surpression on the noisy chips
4. Removing the chips I don't need
I post this to get comments and suggestions on these and other techniques to improve the Juli@.And as this progresses, I'll update my original 'Juli@ Follies' sub-thread on the cMP thread: http://www.audioasylum.com/cgi/t.mpl?f=pcaudio&m=48851 to provide a single place to capture the reference data about the Juli@.
Greg in Mississippi
Everything matters!
Edits: 10/13/11 10/13/11Follow Ups:
Today i accidentally put 3,3v on the 5v-point of the Juli@ and it worked. I use only the digital part.
The 5v 'fingers' of the card are broken to disconnect the mobo-5v. 5v is suplplied by a linear psu. The regulator is capped before and after (capped 5v-grnd and 3,3v-grnd).
Today i used this psu to charge a LiFePo4, so it was set to 3,6v to do so. Later on i reconnected the Juli@, and forgot to set the psu back to 5v. Juli@ worked! Then i connected the LifePo4 to the 5v-point of the Juli@ and it sounded better than with psu.
I checked the datasheets of the digital chips, and they all work within the range of 3,0 - 5,5v.
Next step will be desoldering the regulator and feed 3,3v to both 5v and 3,3v holes on the Juli@-board.
Still, could somebody try this tweak and report, because i'm not shure i did right. If it works right, we could save one supply on the digital part of Juli@.
Douwe
Hi Douwe,
I can confirm it.
I could easily check it.
I have 2 power lines running from a 5 volt linear PSU.
One power line runs too a 5 V -> 3,3 V regulator and from here too the 3.3 volt input on the
Juli@ card (I unsoldered the stock regulator).
The other power line runs too the 5 Volt header on top of the Juli@ digital part.
(I use optical out too my Lavry DAC)
I hooked up this second 5 Volt line too my TTI PL330TP linear PSU and regulated it down from 5 V too 3,3 volt.
The juli@ digital part keeps working on 3,3 Volt.
On 3,3 volt the current is 0.13 A.
On 5 Volt the current is 0.18 A.
On 2.2 Volt the Juli@ digital part stops working.
So you are right.
Only 3,3 Volt will do.
I hear no sound quality differences between 5 Volt and 3,3 Volt.
Nice find.
Mark
cMP2 PC > ESI Juli@ > Van den Hul Optocoupler MkII > Lavry Black DA10 > XLR Mogami Gold > Klein & Hummel O300
Yes there is...right at the bottom of where you post a response you will see E-mail replies...just check the box.
That sounds real promising. I am not able to check this because I need to buy another juli@ to experiment with. I once used a 12 v lead acid battery (regulated down to 5v) to power the 5 volt rails but I ended up frying the juli@ card and was reluctant to go back. But If I could LiFePo4 (which I use for the 3.3v feed) that woud be real convenient. I have extra LiFePo4's and the requisite chargers. So let me understand you ran 3.3 v to the 5 v hole-through input on the card? Does the LiFePo4 feed go through regulators or did you bypass?
Wow, that's fast theob! is there a setting whith which you are told there are new posts? If so, please tel me know.
Yes, i cut the 5v-fingers, and put the LiFePo4 into the 5v-hole on the card (DVCC1). I did not bypass the regulator, did not feed the P3V3D1 hole.
I googeled on regulators and understand they only regulate if the difference in/out voltage is higher than 1,5v. If not, no regulation (and so passing through the 3,3v i guess). So there would be more to gain by removing the U1 regulator.
BACKGROUND...I've spent much time over the last few weeks planning and executing some of the extreme JulI@ digital modifications I began outlining above. My direction has gained focus and changed somewhat from above:
1. Improve the power fed to the key processing chips.
2. Reduce EMI & RF interference produced on the card & fed into it from the computer.
3. Improve the signal processing.
SIMPLIFIED DAC...Before starting this inquiry, I first simplified my downstream processing by replacing my fairly complicated AK4399-based DAC (6 regulators, dual-mono output stages) with a fairly simple one based on the ESS ES9022. This is a very fine, low-cost ($2!) DAC from the same people who created the ES9018 chip used in Twisted Pear's Buffalo DACs and the latest Oppo Blue-Ray players(among others). It is an I2S-input only chip (like the AK4399 and many other modern DACs, but unlike the ES9018) with an onboard output stage. Only a single power supply of +3.3v is used for both the digital processing and the output stage. It uses an onboard charge-pump to create -3.3v to allow its output stage to provide a full 2v level.
With only one voltage feed (most high-end DACs such as the ES9018 and AK4399 have at least one for the digital processing and one for the analog processing, if not more) and very minimal options that can be selected, I thought this was a good way to minimize the variables so I could better hear the impact of the Juli@ mods.
Here are a couple of pictures of my initial implementation of the ES9022 DAC card (provided by EUVL on DIYAudio) mounted on a baseline-modified Juli@ digital section. The Dexa regulators are used as pre-regulators here:
Here is the same card with the Dexas bypassing the on-card monolithic regulators:
BTW, some have suggested that a very good implementation of the ES9022 (and its replacement, the ES9023) will better a merely-good implementation of the ES9018, so I do not feel I am limiting myself by going with this $2 chip. (see the last few posts in this thread: http://www.diyaudio.com/forums/digital-line-level/151846-anybody-using-new-ess-vout-dac-es9022-5.html). It certainly competes with my AK4399-based DAC and with the Dexa regulators bypassing the on-board ones, I'd rank it as slightly better.
THE MODS SO FAR...
Before going on to what I've done so far, you might want to go back to my first post in this thread and revisit what I've done in the past to improve the Juli@ digital sections.
So far on this round, I have worked mostly with my first area of focus, improving the power feeds:
1. Replace my traditional input filtering using 2 1000uf Black Gate Standard capactors with a combination of conductive polymer capactors and high-value ceramic capactors. These capacitors are both designed to work effectively to higher frequencies than the BGs. Also, I installed them in a manner to minimize lead length inductance to preserve their high-frequency capabilities. I did this by installing them at the bypass caps at the input to the 3.3v regulator on the back of the Juli@ digital card. These bypass caps (labeled "BCxxx") are helpfully positioned as close as possible to where they are needed, so they are better mounting points for these add-on caps, especially coupled with very short lead:
2. Move the Dexa regulator I have traditionally mounted on a heatsink about 6"-8" from the Juli@ and mount it directly on top of the 3.3v Dexa on the JulI@ card. This again reduces inductive high-frequency loses, both for the 5v chips on the Juli@ and at the input to the 3.3v Dexa.
3. Feed both the 5v & 3.3v Dexa regulators separately from my 11.5v raw DC source instead of having the 5v Dexa feed the 3.3v one. This provided greater voltage headroom to the 3.3v Dexa, but eliminated the advantage of feeding it from a well-regulated 5v source AND the advantage of the short connection from that source provided in #2 above. To gain some of this back, I added more conductive polymer caps at the input of the 3.3v Dexa.
Pictures coming later!
4. Install additional bypass capacitors at the power input to each of the key chips. While the stock Juli@ is well-designed in that it has the small bypass "BCxxx" capacitor on the back of the Juli@ cards at each of these locations, recent chatter on DIYAudio suggests further gains with higher values.
While I haven't measured the BCxxx caps, I suspect they are between .1uf & 1uf. The caps I added are 100uf. *** Update *** The BCxxx capacitors already on the Juli@ are about .5-.6uf each. ***Note that I haven't yet installed additional bypasses across BC10, BC11, and BC12. Since they have other components directly next to them, it is much harder to install the caps here and not cause a short. I have practiced on an old Juli@, but plan to wait until I get through most of the other mods to do these just in case I damage the card when I do them
SONICS?Step 1, replacing the add-on power supply filtering caps provided a very nice improvement in detailing, dynamics, & bass power & definition. Also instrument solidity and texture was improved.
Step 2, provided more of the same, but with the addition of greater instrument separation & layering.
Step 3 was originally disappointing as I did not add more power supply filtering at the input of the 3.3v Dexa. I could hear greater precision, but dynamics and bass took a step backward. Redoing it with the added caps at the 3.3v Dexa input brought back the dynamics & bass and made it an acceptable alternative. Since step 2 & 3 are alternatives, not a direct linear upgrade, I need to go back an forth a couple of times to see if I can identify the differences between them and decide which I prefer. I suspect long-term I will like 3, but I may try an additional Dexa (probably set to 7.5v or so) before the 3.3v one to see if I can get the best of both worlds.
Step 4 added more detailing & separation, but was a smaller improvement than the others so far.
CERAMIC CAPACITORS?
One caution I have on all of these mods so far is my heavy use of ceramic capacitors. I remember Marsh & Jung's Picking Capacitors and how ceramic caps were some of the worse measuring & sounding caps at the time. But I see that several things are different today:
- Back then, audio circuits did not involve much if any digital processing. Today, digital sources are the standard. And building a good digital circuit is different than traditional analog circuits (and this drove the creation of surface mount components, among other techniques). Digital circuits have to be well-behaved in the megahertz to gigahertz ranges. And large, long-leaded teflon, polyprop and polystyrene capacitors just don't work well in these ranges. Making a good digital circuit means doing things a LOT differently than making a good analog circuit.
- Ceramic (and for that matter, electrolytic) capacitors have gotten MUCH better over time. While I wouldn't use the same components in both digital and analog circuits, the small, short or no-leaded ceramic and high-frequency electrolytic caps I'm using here are now good choices and the same components you see in other high-end digital circuits. Also, they are the same type of components already on the Juli@... Just more and better of them.
I did detect a bit of harshness when I first put in any of the ceramic caps... And that has diminished as they have broken-in. With a couple of weeks of time on steps 1 & 2 by the beginning of this previous weekend, the sound was very smooth and not harsh at all. Adding the components I used in steps 3 and especially 4 brought some harshness back, but now a day or two later, smoothness is returning.
WHERE TO NEXT?
My next steps are to continue with improving the power feeds and reducing EMI & RF interference produced by the card. These will include:
5. Remove chips not needed for I2S connectivity... The TOSLINK output, the digital input optocoupler, the SPDIF input/output AK4114, and the SPDIF buffer/selector. I only have a concern about the AK4114 and whether the card will continue to operate with it disabled, so I will try disabling it first on an old, sporatically-functioning Juli@ (one of the first I modified).
6. Reduce RFI & EMI pollution by shield the chips using a stick-on ferrite material and installing ferrites on the power supply lines (Thanks hfavandepas!). I also plan to try conductive foam as a absorber of RFI/EMI, as championed by Elizabeth on the Tweak Asylum.
Then I want to improve the signal processing:
7. Upgrade the on-board clocks using the Fidelity Audio Micro Clock which can be purchased with the two clock frequencies needed for the Juli@. While I don't expect these clocks to equal the higher-priced upscale clocks, I do expect to hear a strong hint of what they can do for the sound.
And finally, complete step 4 by going back & install the additional bypass caps I deferred.
AND BEYOND?By the time I have gotten to this point, I hope to have information on devices I can use to provide galvanic isolation at the I2S interface.
Then my question will be: Will I be stuck using the Juli@ at the GA-H55M-UD2H level or will the H61 motherboards with the non-native PCI slots work ok for an audio setup using the Juli@?
Greg in Mississippi
Everything matters!
Edits: 11/14/11 11/15/11 11/15/11 12/02/11
Hi,
Great job! You are going as crazy as me!
Regarding remove of chips the 74HC125 need not be removed. Alternatively, just lift pin 14 Vcc (the pin above the "D" of DGND1). Check its connection to the reg.
http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXrytxt.pdf
74HC125 is driving the Dig trans and optical output. Without power supply, the trans will no longer work, hence no need to remove. The optical output will not be working too, but it will still draw a small amount of current.
Edits: 11/20/11
Jack,
In any case I did just what you suggested for the 74HC125. BTW, the comments made (partly by you) in the thread about a year ago on a tube SPDIF buffer thread here helped me understand how that part of the Juli@ card works... thanks!
I also removed the TOSLINK connector (by un-soldering it) and the digital input optocoupler (by just twisting it off with pliers, since it is an easily-obtained part if I wanted to undo the change).
Immediate results (no break-in time for something like this!) seemed like a slight increase in HF clarity, but was not large. I have higher hopes that un-powering the AK4114 will produce a larger improvement, but I still need to confirm that it's removal won't stop the card from functioning in I2S mode. I have an older, somewhat sproratic Juli@ that I'm setting up to test this and I hope to do that test sometime this week.
I am still getting a little of what I identify as the ceramic cap signature. They've been running in for about a week (maybe 150 hours total on-time)... If it persists over the next several days, I'll try disconnecting them. If that removes what I'm hearing, I'll try different caps there (small organic polymers next). Got any suggestions for a good low-inductance local digital circuit bypass?
A related question here... back when you first posted here about your extreme mobo mods, you'd suggested that you were looking at simplifying the process by just cutting or disconnecting power pins instead of doing full chip removals. Now in your latest posts on removing chips, cutting power pins is not mentioned. Is this is a bad option for eliminating chips on a motherboard? Not that I am afraid of pulling chips, just lazy!
TIA!
Greg in Mississippi
Everything matters!
Greg,
I don't think AK4114 can be removed, it should be responsible for I2S output. See p.29.
http://www.asahi-kasei.co.jp/akm/en/product/ak4114/ak4114_f04e.pdf
Ceramic cap never sound good to me. Oscon caps do a better job than ceramic, Siemens Sikorel is even better. I also like Philips or BC but they are no longer available. Panasonic caps (those 105 *C, series M or FM, body in blue and word in gold colour)do a decent job although they aren't as good as the above or Black Gate.
For GA-H55M-UD2H, the following can be removed by cutting of their legs off and removing legs by solder,those smaller ones like video chips are too small to be cut off (I've tried):
- IDE controller next to the P24 connectors. However, the regulator below the roll of 3 SATA connector must be removed by desoldering.
- the sound chip at the corner
Better SQ improvement can only be done by removing the video chips however.
I just found it more neat and tidy using hot air gun to remove chips. Now I can heat up the chip directly with a temperature controlled hot air gun (just bought) and pick up a chip with a sharp nose plier. Tried on small chips like the video one on unused boards with full success without tamper with any other components.
Good luck
Jack
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: 11/21/11
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!
To remove chips, would it be posssible to only cut the power-pins of the chip? Maybe more easy to do than removing the whole chip. I'm asking because i'm thinking of removing chips from mobo.
Douwe
Douwe,
That should work ok in almost all cases... and if you plan ahead and do it carefully, you can reattach it if things don't work as you expected.
I will be doing that when I test disabling the SPDIF-related chips from the Juli! I'm pretty comfortable I can remove the opto-coupler, the output connector, the TOSLINK connector, and the buffer, but not as sure on the AK4114. I plan to carefully lift the PS pins on that chip using a fine soldering iron and a needle to make sure my I2S outputs still function with that chip disabled. If it does, then I can remove it completely.
Let us know what you do AND POST PICTURES!!!
Greg in Mississippi
Everything matters!
Thanks Greg, for me it will take some time (job, family) i hope to work on it during christmas holidays. Will post pictures then.
Good luck with the Juli@!
Douwe
Rick McInnis, Dawnrazor, & Mihaylov, thanks for the discussions about the Lynx recently in the cMP & cPlay threads. This prompted me to go to Mihaylov's site (which is a treasure trove... thanks Mihaylov!). There I found a link to the Fidelity Audio website where they have a small, dual output clock module (their Micro Clock) that looks like it would be a GREAT upgrade for the clocks on the Juli@. It comes stock with what on paper appears to be a good regulator & voltage reference right onboard plus it features two seperate clocks and can be had in the 22.5792 & 24.576 values needed for the Juli@! And at it's pretty affordable for two high-quality clocks with on-board power!
Yah, one building block found!
Everything matters!
Hey GStew,
I wish I could compare the lynx and the Juli@ for you guys, but I dont have the Juli@ and well I use the analog outs anyhow. But I think the Lynx can be everybit as good as the juli@ if not better in terms of the digital out. I say this because of Gordon Rankin:
http://db.audioasylum.com/mhtml/m.html?forum=pcaudio&n=15599&highlight=stellar+Gordon+Rankin&r=&search_url=%2Fcgi%2Fsearch.mpl%3Fforum%3Dcables%26searchtext%3Ddcca
High praise indeed considering the source.
The Juli@ though can do rates past 96k while the Lynx is limited to 96k. Looks like the Lynx has a smaller driver footprint.
Anyhow your post about a clock echos my own thoughts in a general sense. I have been looking at the antelope clock and wondering if that would be a good thing to add to the lynx. Though I cant quite figure out if it would work with the Lynx. I bet it does. Any thoughts??
No one here remembers the bending of our minds
is it almost too good a price?
Looks like it still uses crystals but maybe they all do. One wonders if you are going to go to the trouble if it would not be better to get two of the good ones? The good one is using a crystal too but looks like there is all kinds of other stuff on the board to "correct" it. Of course, there are those, namely Peter Daniel, who think these things sound worse than the crystals they replace. I have never experimented with any of this stuff but I tend to think Peter is right. I am sure the sound is different! Simplicity has much going for it and I tend to think the lowly crystal might be the best compromise.
I have seen somewhere someone selling calibrated crystals, or I suspect, more precisely, selected crystals to get as close as possible to the needed frequency. This seems the best way to me. I will try to find those again and let you know. I am nervous about removing components from the board.
I am intrigued with your improvement ideas but can tell you I would be really nervous removing those big IC's from the JULI@ board. It is fragile; bad enough using those SMD pads for "regular" caps, can't imagine what would happen from the heat required to remove something with forty pins! Micro dikes would be safer if there is such a thing.
Please tell me more about NOT using JULI@ CONTROLLER. Have you removed those drivers and does JULI@ still work? Sounds like a great idea if it will work!
Take care,
AFAIK. So that's not a problem.
My read of the additional circuits on their clocks are that both of them include significant power supply regulation and referencing... better on the premium, but not bad on the micro. Then the premium also has a buffered output (to drive longer cables from the clock) and divided outputs (1/2X, 1/4X) needed in some equipment, but not needed for the Juli@.
But since one of their premium clocks costs about 2x their micro clock with two clock outputs, you'd spend 4x as much to use two of them. And they look to use the exact same crystal module... just better power and optional outputs on the premium module.
I don't doubt their premium clock would be better, but I also have seen Peter D's comments and am looking for a way to try a better clock without breaking the bank in case I decide (like Peter) that I prefer the original clocks.
I also like the size. I'm planning to hang a lot of stuff off the Juli@ for this round of mods... their micro clock should still fit right on the board and give a very short clock signal path. And if I like it, I can do some power supply upgrades that will move it towards the premium clock's level.
And I think the main benefit of going with add-on clocks for the Juli@ is because you'd be powering them with separate power supplies which would be MUCH cleaner than motherboard power and even cleaner than the power on a Juli@ that has separate supplies (due to all the processing that's going on in the Juli@ itself polluting the voltage rails). Providing the clocks with their own cleaner supplies would improve their accuracy, stability, & jitter level. And probably sound better.
As far as selected clocks, my understanding is that clock stability & lack of jitter are more important than the absolute frequency. You don't want them to be far off, but I understand that high-quality crystals are pretty darned close. Someone please correct me if I'm wrong.
Then as for un-soldering chips, I agree that could be a real pain. The devices I want to experiment with removing are the ones associated with the SPDIF output... U6 & U8, PC1 & PC2, J4, and OPT1. The harder ones are U6 with 44 pins & U8 with 14. When I experiment, I will use a 'junker' card & carefully pry up only the power supply pins. That way I can reverse it if there's a problem.
BUT if it works out ok, I'd just plan to cut them out with an X-Acto knife or similar, which shouldn't be too hard. The other devices are all much simpler to remove with most of them being through-hole devices.
Really, the hard part will be soldering on the additional filtering caps.
Later!
Greg in Mississippi
Everything matters!
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: