XXHighEnd

Thanks to Anthony for this one. Yesterday I received an AUDIO GRADE USB 3.0 PCIE CARD - the one that Anthony is using and can be found here here: -

http://ppaproduct.blogspot.tw/2013/07/audio-grade-usb-30-pcie-card.html

This card is all about low jitter with a special low jitter clock and a custom wound silver o/p transformer.

With ten hours burn in I have to say I am surprised by how much this has improved the sound. The whole range is improved from top to bottom. A glassy hard edge has been removed (although I have to say I did not think there was one before!!). The sound now really has an analogue quality. Elvis Costello latest album "Wise Up Ghost" (what a great album IMHO) has a hard over processed edge to it like most of his previous albums but is sounding almost analogue and warm now - voices sounding real and warm instrument tone much improved.

So why a "Bert Must Have"? well Peter has told us that jitter sends him totally crazy.

If anyone else has one of these cards I would be interested in their feedback because here the improvement is not subtle.

Cheers

Paul

Wow...glad you got one and like it Paul.  Like I said earlier I have not compared my card to the mobo port because of the difference the card made with my previous pc and dac, but I should do that.  If your card burns in like mine it will get to its best at about 200 hours with further extension both high and low.  I have the original V1 card and you would have the V2 card.

On my previous setup this card really improved again with a good linear power supply.

Cheers,

Anthony

Ok ok ! I will order one too... But what to do with the Sotm USB 3 PCIe card... use it to plug my keyboard or my mouse ;)

Alain

Done !

To put this in perspective I hear a much bigger improvement in sound quality with this mod than I heard with the upgrade in the clocks in NOS1. But there again I expect that the two upgrades work together - with the improved jitter in the USB signal in perhaps we can expect that the NOS1 clock upgrade really starts to show.

Cheers

Paul

Haha Paul,


If you don't mind ... I have no idea what you are talking about here !

Peter

This goes back a long time but in the early days of this blog I seem to remember you saying that Bert had a particular aversion to jitter. Or maybe it was someone else and my memory is going?

Cheers

Paul

Paul, that guy is named Carlos and it is through him how I started XXHighEnd. I just searched "jitter" in this forum and the oldest post which comes up speaks of him.

Regards,
Peter


PS: Why XXHighEnd ? (http://www.phasure.com/index.php?topic=5.msg8#msg8)

Ah my memory I must get a new one or an upgrade!!

Paul

Hi Paul,

I've just fed my PPAstudio card with a cheap lab linear 5v rail...a nice step-up in performance again.  I wonder what a 'good' linear psu would achieve?  I gave a brief rundown of changes the linear psu made over in the linear psu thread.

Cheers,

Anthony

Thanks for this experiment Anthony and thanks for doing all of the "heavy lifting." I've gone ahead and ordered Paul Pang's usb card and can't wait to hear the difference it makes in my system. I wonder now, however, if I should also be thinking of upgrading the PSU in my XXHE PC(you've just gotta love this hobby!). Along those lines, if you have thus far gotten good results with a relatively less expensive linear PSU, what higher end PSU's are you considering next(specs and all)? Also, how would the Sonore PSU fit spec-wise with the PPA card and XXHE PC?

Esau

Hi Esau,

Please let us know how you go with the PPAstudio card, good or bad.  The more impressions of this product that we get with the NOS1 the better, and if we are lucky a general consensus will emerge and we will have found a reliable cheap upgrade.

I will work through the linear psu thing for the XXHE PC in the coming weeks so keep an eye on that thread.  My audio system with the NOS1 sounds so good right now that I reckon I have plenty of time to thoroughly work through the linear psu stuff and end up with the right power supply in the end.  Who knows, at the end of it all there might be a product that you can build yourself or have someone build for you.

Cheers,

Anthony

EDIT:  I just re-read your post Esau, and I failed to answer one of your questions.  The linear psu project is designed to spec and design a multi-rail linear psu especially for the XXHE PC.  This means that an off-the-shelf supply is probably not going to be either available or suitable for the job so I foresee some kind of diy in my future.  It would be nice if everyone that wants one of the supplies can either make their own or have someone make it for them.

Well, I stil have the XXHE PC but the NOS1 was sold a year ago to my good friend AlainGr(yes, that Alain). Alain, alas, does not own the XXHE PC(at least as far as I know) but he does state that he has plans to purchase the PPAstudio usb card.  Perhaps when my economic portions have improved a bit(i.e., my wife finishes remodeling our home - we had our kitchen totally gutted and remodeled and now we're adding a 2nd bay garage with a deck on top) I'll be able to purchase another NOS1.

Anthony, thanks again for the information on the linear PSU. I'm not a DIY guy but I know someone very capable who would build one for me for a reasonable fee.

Esau

Anthony hi,

There is potentially a cheap way to see how much headroom the TCXO power supply has for improving sound quality.

I found the supplier of the piggy back board on your card online before I built my DIY clock and looked at the layout. I think its likely that the TCXO is run from a 3.3v supply derived from the 5 volt supply going to the piggy back board. It would be easy to check the pins on the TCXO with a volt meter to see if this is the case.

If it is a 3.3v supply then powering the TCXO with a 3.3v nominal voltage A123 brand LiFePo4 battery will give you an idea of what a really very good quality linear supply will do. I tried these batteries after reading about John Kenney's experiences using them to power clocks in his HiFace modified interfaces. There like nothing else I've come across.

It's important to get the A123 brand as the chemistry is different to other brands and this makes a difference. If you can find them 2100mah A123s are about £10 (uk). A good place to try is suppliers of radio controlled model cars and plane. With one of these batteries the chances are that you can leave the clock running for 2-4 days between charges so could even be used longer term but testing this way will really highlight if its worth investing more money on a good linear supply for the VCXO.

Cheers,

Nick.

Paul hi

I don't know that card you have well so I'm making an assumption in the comments below that the card has both the USB chipset and or the USB 5v inline supply and the clock powered from the molex supply plug.

If this is the case then I'm not surprised that applying a "clean" supply to the chipset and or 5v inline supply does not sound so good. I think this may be a similar situation to what was happening here.

http://www.phasure.com/index.php?topic=2640.msg28369#msg28369

Again assuming that the usb chipset / 5v inline supply and clock are fed from the molex if you were to isolate the clock supply and put the battery or linear supply on that only but keep the molex connected to the SMPS then I think the result might be a good one. The only reason this seems to work is that the clock is transformer decoupled, so the good supply to the clock improves its performance but does not influence the USB chipset / 5v supply.

If the assumption about the molex powering both the USB card and or 5v inline USB supply and clock is wrong then please disregard these comments, time to think again :)

Looking forwards to hearing the card at mine when you come by.


Cheers,

Nick.

Nick, I reckon you guys should pull that card out after you listen to it so you can have a good look at what has been done to it.

Keep us informed.

Anthony

Anthony hi,

I'm really keen to take a look at it, also to listen to my modified card along side it. Im guessing Paul is focused on tweaking it so some of the details may out before we get together  :). I'd be interested to put my scope on the clock. It wont tell anything about phase noise etc but will give a picture of signal amplitude and rise time. The key points from messing  about iv done here appear to be oscillator performance, quality of the decoupling (the transformer and matching) of the clock circuit and the clock's power supply. No surprises about these factors but as always implementation is so important so i'm really looking forward to seeing Pauls card.

Best,

Nick.

Hi Nick,

I have the audio grade usb3 card and did some test today. First I used a external battery Konig 5V-2.1A 7000 mah (normally used as backup for an ipad) via a usb-molex cord. This is no success! Maybe not a good battery to test with, but that is the outcome. Next I tested with an external linear peaktech lab power supply. Much better. But the normal internal bequiet power supply (pure power 530W L7) still beats that....

Some other results of the tests: PC without the hood is much better, more open sound. Also the harddrive outside the pc box made a nice improvement.

I have a little problem with the usb card, only the 5V leads may be connected. It seems that the card is leaking through the 12V leads. But it works fine without the 12V leads in the molex.

I checked the card it seems that the additional components are connected via some small leads soldered to the molex. So connect this to a separate battery seems possible.

kind regards 

Further tests with the USB Audio Grade PCie card. The card comprises a normal USB3 PCIe card with a piggy back card that has a low jitter clock and a silver output isolation transformer. The piggy back card picks up 5V from the incoming MOLEX connector which I disconnected I then connected a dedicated linear 5v supply to the piggy back board. The supply from the PC SMPS remained connected to the molex on the main PCIe card.

This seems to be slightly better than having both the PCIe card and its piggy back card from the same supply from the Seasonic SMPS. But it is a small improvement I would say.

The piggy back board seems to have a DC to DC converter but it has a big heat sink glued to it so not easy to see but anyway it probably produces 3.3V for the clock. It gets the heat sink warm to the touch so it is probably a regulated supply rather than "chopped" supply - it would be interesting to see if a battery supply 3.3v direct onto the clock improves things. Well maybe but it is not an easy thing to do with this board maybe something to do on a rainy day.

Cheers

Paul

Hi Akremer,

I'm going to get a look at the card when Paul comes over to mine soon. As I mentioned above if the molex powers either the cards USB chip or is used for the 5v USB leads power supply then using a supply other than the pcs own internal supply proberbly won't sound best. My guess is that the PCIe bus signal / USB d+ d- signal suffers greater noise if the signal source and end points are not powered by the same supply. If this is right then it's better to use the pcs supply as this is used at both ends of the PCIe bus transmitting  / and receiving the data.

The exception is the USB boards clock power supply. If this is isolated from the power to the isb chip and the 5v usb lead supply then using a good supply is likley to improve the clock and since it is transformer decoupled at its output the smoothed supply to the clock doesn't cause the problem above. I think Paul's post is saying he found the clock supply to make a small difference.

I can not measure to pinpoint these ideas so could be something else happening.

Cheers Nick.

Yo,

Although this is not completely off topic, I have the feeling it is distracting.

Peter

Peter hi,

Yes definatly off topic, might it be a good idea to move the last 8 posts concering the clocked USB 3 card to this thread ?

http://www.phasure.com/index.php?topic=2749.msg28645#msg28645

Regards,

Nick.

Ok, I just did so. Thank you Niick.

Btw, split from under this post : Re: Investigating a full linear PSU for the XXHE PC and NOS1 (http://www.phasure.com/index.php?topic=2726.msg28777#msg28777).

Peter

Now I've had this card in my system for 300 hours and I am sorry to say that it doesn't deliver the goods.

The burn stabilised at about 200 hours as indicated by PP.
I've noticed a mounting issue late in the process, but fixing that didn't bring the sq forward.

The card deliveres a smooth subtle kind of sound where all sharpness has been tweaked out. The tone can be described as natural with lots of details. However, the low end is unfortunately completely gone as is the impact of the fundamentals, leaving the sound robbed of dynamics and musical momentum. Also I've noticed "strangeness" for lack of an adequate description in echoes and instrument decay. Note that most listening was with win7.

Other XX settings did not bring any relief.
Furthermore I've found that the sound was somewhat inconsistent, sounding better or worse at times even after burn in.

Installing the old card again, the sound becomes much more interesting and instruments have real body again. This is especially noticable on the sound developement (attack, decay etc) of keystrokes on the piano.

Regards,  Coen

I forgot to post some ponderings about this experiment.

1) an "improved" clock at the pc side does NOT make the influence of XX settings powercords etc inaudible. Actually they have the same effect.
The PC "noise" is still able to slip through. Maybe for the better ;).

2) the perfect clock signal and its alledged beneficial effects may be ruined at its implementation. To me the x former is highly suspect, it is able to pick up any noise in the PC since it is unshielded.

3) I think this "better" clock needs to be at the other side of the USB cable ie in the NOS. First any good clock gets noisy again as it passess the USB link (pcb, contacts, plugs, cable, etc). Second the USB mode of operation (async) sets the timing on the receiving end.

Some food for thought for those who are experimenting with clocks. I am looking forward to your findings!

Regards,  Coen

Great stuff Coen.

I myself think that any transformer isolation will radiate as hell. But this is quite personal thinking as usual.

Best regards,
Peter

Coen,

Not a great result, sorry to hear the clocked card is not working out there. I have not heard the card you have but will get a chance in a couple of days, Paul will bring his PP card to my place so it will be very interesting to take a close look and have a listen.

The replacement USB clock I built started out with a similar sized SPDIF transformer but this was only temporary and it was replaced quickly with a 100mhz rated micro signal transformer / choke combination. The replacement units are targeted at ethernet isolation. Anyway sound really improved. Another thing that helped was capacitor decoupling the transformer on its input and outputs but capacitor size was important to sound. This all sounds like it would degrade the waveform but it seems not from the audiable results.

Re-reading your experiences it sounds like something is wrong. It's really the opposite  of what I would have expected. Of course is could be that you existing set could just have an excellent USB port setup at the PC and the new card is just not a good !

Anyway I'm looking forwards to hearing Paul's PP card and we will report back on what we hear.

Regards,

Nick.

Coen hi again,

I'm defiantly with you that the transformer is very important I don't know about the PP card's trafo so could not comment specifically on that.

I was looking through USB host chip data sheets and it seems they commonly use a x 20 multiplier circuit to generate the 480mhz line speed of the USB link from the 24mhz clock. My thinking was phase noise in the 24mzh base clock that generates the 480mhz clock has to be a bad thing. With this in mind the transmitting USB device's clock phase performance could be important. I'm trying to find an explanation of how this happens but at the receiving end the USB chip will have to 'clock in' the data as it arrives. The clocks at both end of the link are nominally 24mhz (for the NOS and and NEC usb chipset at the PC) but they will not match exactly. For this reason I'm guessing that the receiving USB end my have to lock onto the transmitting (480mhz) data rate and it might be that a good clock at both ends improved to stability of the lock and reduces transmission errors.

Experience here has been that the PC end clock does help quite significantly but the largest difference by far has been changing the clock at the DAC end of the USB link.

Best regards,

Nick.

EDIT put the /quote in the wrong place

Interesting report Coen, and very informative in a number of ways.  One of the things that I have always wanted to do since I got into this computer audio thing is to build my own pc case.  There are a number of reasons for this but one of them is so that I can run the USB card in relative isolation to the mobo and power supply to minimise the amount of unwanted electrical action between them.  I have toyed with building a little metal shield to slot over the USB card in an attempt to isolate it, but have always come up with other projects.

I have the original V1 version of the PPA USB Card, which is a more elaborate and more difficult to build version of the V2 card that you have there, so there are some physical differences, but my listening impressions are quite different to yours Coen.

Based on your reports, and Nicks experiments with the NOS1 USB clocks, it does seem at this stage that the best gains are to be made with the NOS1 USB clock.  I really want to hear about the Nick/Paul get-together this weekend and associated investigations and impressions.

Cheers,

Anthony

Hi all,

Thanks for the replies. I genuinely feel that there is very little positive to report especially now my regular card is working out splendidly.


Its not what I expected either, but somehow this doesn't work out.
I allready have an (rather cheap) IBM OEM USB3 card with similar TI chip. It does draw its power from the PCI-bus and not from a separate Molex and it has bigger on board buffer caps. The crystal seems some generic type in a cylindrical container. Maybe its just a lucky combination in my setup.
Perfect? Well it does work particularly well, but I can identify areas that could be improved upon. I consider archieving these improvements a bonus rather than a neccessity. With the PPA card the sound was and remained unacceptable.

Anyway I am also interested in the findings of others about this card especially when used as intended so power from the psu and no batteries and stuff for the clock.
An "improved" clocking still seems like a good idea though Peter may have run lately into the limits of lowering the noise (like the phase and amplitude noise in the clock signal). At present time does not permit experimenting with clocks in the NOS1. I am not surprised sound differences are more profound there.

Wrt the working of USB2/3 likely the datasheets of the chips will state the tolerance between the masterclock and the external clock. Internal circuitry of the USB transciever will lock in if you stay within these limits. The main benefit of a better clock is a lower (phase) noisefloor IN the substrate of the chip translating into less (phase) noise on the datalines and thus in the DAC chips. Something like that, because the DAC clock signals are generated by separate clocks.

Though we can reason out a lot only the experiment will tell what it practcally means. Keep up the good work guys!

Regards, Coen

I really start to wonder ...

For a completely different project I have had made a bunch of small PCBs which go in beteen USB and the DAC board and they digitally isolate the i2s. This can not work in itself because it implies 250ps of jitter caused by the isolation chips;
I had the PCBs made to proove that isolation can't work anyway for several reasons in my mind and they were made for testing on the NOS1. So, it is my assumption that it goes wrong for other reasons than too high jitter (and notice that the NOS1 oscillators carry 200fs of RMS jitter, while this thus implies 250ps - some 1000 times more).

But what if it works after all, outside of the jitter issue ...

From another situation I already know how this amount of jitter sounds and I think it is just enough "doable" to judge whether any PC (or USB) influence can still be passed on. But who knows, maybe the net result is even better. So while I have these PCBs laying around for 3-4 months by now, maybe I should put some components on them and try it out.

In the mean time, right at this moment we're applying the 24.xxx audio oscillators on USB ... See if Nick's failure on this happens here too ...

Peter

At ordering the components I just saw that it is 100ps. Still bad but better.

If you want it to work with an VCXO if it doesn't I think you will have to make the voltage slightly adjustable to stay within the USB chips timing tolerances...

regards, Coen

I originally wondered about the Molex on the pcie card. I think this has to do with cost savings to provide for a powerfull USB3 spec 5V line (X2).

On second thought this introduces an undesirable architecture.
Now the PCIe will only provide for 3.3V, 12V and Ground. Connecting the molex a second 12V and Ground path are introduced only to harvest the 5V. Not good.

So ideally the molex is not connected. So can the card do without the 5V? The NOS1 can. We can use a separate molex adapter to feed the xtal with a "star" 5V since it is galvanically isolated. I am not shure of the latter however since three wires of the xfirmer are terminated on the clockboard.

Anyway i makes sense that the effect of the card is psi and motherboard dependent and that the mod could and should be modded!

Regards, Coen

Coen hi,

Peter is working with the audio clocks used in the NOS, they are fixed frequency and the specs are exceptional but unfortunatly they are not available in 24.000mhz. The closest frequency available is 24.5mhz, when I tried these out I could get the PC USB card to work with the 24.5mhz oscillator but not the NOS interface end at this frequency.

It would be great if they can be made to work though.

Cheers,
Nick.

Coen, exactly my thinking. And I am almost sure it will work without the Molex connection. Will try tomorrow ...

Peter

Guys,

Best sound here is from powering both the USB chipset and the 5v aux usb supply from the PCIe 3.3v bus rail.

I think it is possible that only having one common power rail noise spectrum on the 3.3 volt supply to each of these systems helps prevent the NOS USB d+ d- lines, and the data transmitted from the PCIe bus the USB chipset from seeing diferential noise from separate supplies. The 3.3v power from the pcie bus rail may not be the ideal but at least there is a common noise spectrum experienced by bus components the USB chipset and in the 5v aux usb supply.

The USB card clock performs best for sound quality here with a high quality low noise separate supply but only if the clock and its power supply are decoupled from the USB card by a transformer. Leave out the transformer and prepare to listen to jitter  :(

In summary USB card power and 5v aux USB power from the PCIe bus and USB clock power as clean as possible but transformer decoupled clock.

Hope this is useful.

Best,

Nick.

Hi Nick,

You're well Ahead of us but we're catching up!

As far as I can see now the ppa transformer does NOT galvanically isolate the clock. Two red wires are attatched to the clock output ports where one is connected to the ground. Peeking between the clock and usb board i can see that the former is connected to a (one) film capacitor which in its turn is connected to one of the old xtal pcb islands. The other island seems not connected. There is a black wire from the xfomer to the clockboard ground. This is either a screen or shield or the second leg of the x- former output. I think the latter so no isolation... Why then use an x-former? Bandwidth limitation? Voltage adaption?

I'll take off the clock board tonight and see whats really below it.

Regards, Coen

Hey Coen,

Maybe it could be nice (well for me) if you can more clearly talk about what you see. For example, your "the former" seems to refer to two (!) read wires while I think you mean one of them, which now makes not much sense (to me).
Also, you might put some attention to
"i can see that the former is connected to a (one) film capacitor which in its turn is connected to one of the old xtal pcb islands."
which to me seems wrong in the first place. Not sure, but I'd say that this "former" needs to be connected to the old xtal island which from there goes to ground through the cap. Or ?

This is all not crucial of course, and it seems that I try to help you which I don't think is necessary at all. However, I am always eager to find messed up things (designs) and this seems to be one.

Btw and might that help, an active osciallator (not voltage controlled assumed) has "inputs" for voltage and ground, and for output the one clock wire;
Running the output through a transformer might not be the best idea for the signal itself (I keep on saying that any analog device is too slow for this) but may imply groundloops again (somewhere at the other side). But the supplies (gnd and V) can sure go through the transformerS.
For real isolation it needs three transformers, but I'd still wonder what happens with the still not-isolated ground at the other side.
We (or I) can also say : this never can work unless far (!) more complicated schemes are applied, and they won't lend themselves to apply on existing designs. That's what I think of it.
Mr. Pang (I think is his name) may have found himself for the same half-decisions. Any good for the better ? I again don't think so because the result will be out of (veryfiable) control ?

Peter

Hey Nick,

I can't even get that to work (with the 24.5);
Questions :
Did you power the card through the Molex for this ?
Did you install the (Nec) driver or anything else for this ?

The card with the original oscillator works here with neither. So I wonder whether it needs more with the notice I can't easily pull a Molex supply from the PC (read : not all that easy to briefly try whether this helps).

Thanks,
Peter

Peter hi,

The USB 3 card that worked with the 24.5Mhz clock has an NEC chipset (2 port) using the standard windows 8 driver.

I removed the standard 24mhz crystal and its resonant caps and connected the 24.5Mhz "audio" clock. The test clock was powered by Battery and between its output and the NEC USB cards clock inputs its was decoupled through a signal transformer. The USB card was plugged into the PCIe bus for power so just standard PCIe power no use of Molex etc.

It may be the type of test you are trying, I did not do extensive testing on the card with the 24.5Mhz clock. It showed up on device manager and I could read an attached USB stick drive without problem in Explorer but it would not manage connect with the NOS.

Hope this helps.

Best regards,

Nick.

Sorry missed this. You have me there.. :)

This is strange surely that should work. I know you mentioned it is hard but maybe if you can just power the card from the PCIe bus and debug from there with the standard clock in place.

Could it be  windows 8.1 driver problem by coincidence ?

Regards,

Nick.

Yea, I knew that would go wrong with my English ...

"Works with neither" was meant to be read as : Just works with the normal MS driver and without the additional Molex supply.

Ok, thanks. But probably we tweaked the 3.3V supply wrongly; this was some digging in datasheets and where to get the 3.3V from, because it is quite tough to measure while it runs in a PC case ...
(yes, a battery would have been more easy, but I didn't want to do that)

Cheers,
Peter

I was wondering... When you mention that the molex is not necessary, how to let XXHE know that the connection is established with the NOS1 ?

Alain

Alain, because it's (3.3V) just fed through PCI(e). Well, I didn't examine whether it is really 3.3V in my case (can be 5V ?) but the NOS1 doesn't need any supply through USB, so ...

Peter

I know this, but I did the test this week-end (I left the molex disconnected)... XXHE brings an error message saying that there is no sound card... And there isn't any to select... As soon as I connect the Molex, all is back to normal...

?

Alain

Here it works without the Molex. I think others claimed that as well. Quite confusing ...

To tell the truth, the only way I could "cut" the 5V was with the Sotm card and only after starting XXHE for the first time in a session...

So that is confusing for me too...

Alain

Alan hi,

I think you said you were getting a Paul pang card. If so, looking at Paul's last weekend the clock is powered from the molex. If the molex is not connected there is no clock signal to the usb chipset so the card will not run even though the USB chipset is powered fon the 3.3v PCIe bus rail.

If your not on a Paul Pang card you got me  :)

Cheers,

Nick.

Hi Nick,

You are right with everything :) I have a PP card now, I removed the Sotm card.

I was not aware that the 5V was for the clock... But is it also used for the USB power running from the PC to let's say a powered USB device ?

Regards,

Alain

Hi Alain,

I am having a look at the V2 PP card and I don't think that the 5V for the USB port is generated from the Molex plug, I think that it comes from the PCIe port.  Power goes directly from the Molex plug to the clock (which is the yellow board that is offset mounted) and I see no sign of anything other than the clock signal going to the usb card itself. 

Regards,

Anthony

Alain hi,

IIRC when usb3 was introduced the new maximum current for the external 5v supply to connected devices went up. This means that up to about 0.5 amps per usb port cards use the 3.3v rail of the pcie bus to make the external 5 volt supply with a dc to dc converter. If your external devices need more than 0.5amp you use the molex, which can supply greater current to the 5 volt external supply.

So the 5v external supply comes from either the pcie bus or the molex depending on if you have the molex connected. The usb chip always gets power from the pcie bus 3.3v supply. I think the Paul Pang card works in this way as well. It also takes its clock supply from the molex from what a saw of Pauls card.


Hope this helps.

Nick.

Of course...I did not even think of the existing connection for the Molex plug.  So probably yes, the 900mA (top end of USB3 spec) for the USB port may well come from the Molex plug.

Hi Anthony and Nicks,

Thanks for the precisions. This brings a new question... I actually use a iFi iUSB power supply for my external SSD (contains the OS + XXHE)... Would it be (better: could it be) better used if I modify a cable to allow for a molex adaptor to power the molex ? Or would it just increase some other problems ?

Regards,

Alain

Sorry for being so cryptic about the clock signal isolation transformer.

If you still want to byte into it here's the deal:

In short the clock isolation transformer has:
- a primary winding with one leg connected to the clockboard ground and
- a secondary winding with one leg connected to the clockboard ground.

There is also:
- a black wire form the isloation transformer that is probably connected to the shielding of the transformer. It is soldered to clockboard ground.

- the second wire of the primary is connected to the output of the crystal oscillator (wich is dc decoupled by a small capacitor first).
- the second wire of the secondary is connected (via a film type capacitor) to - only - one of the connections where the original crystal has been on the USB3 board near the NEC chip.

The groundplane of the clockboard is connected to the USB board ground ONLY via the ground of the 5V supply (the twisted silver and red wire).
This was kind of a relief since now it is NOT an alternative groundpath of the regular USB card circuitry.

In short primary, secondary and shield all share the same clockboard ground. I think in this case clocksignal return currents have to travel however via the 5V ground wire. This must be some kind of trade off since I think the way that Nick solders both secondary wires to the original clockmounts (don't you Nick?) would be the way to go...

As far as I have been able to investigate the 5V is supplied via the MOLEX and is filtered by a pi filter with a "big" HF choke (top of the board) before being offered to the pins. Marketing rap says this will increase the quality of the data transfer (less loss, higher speed). So forget about a similar noise spectrum here....

I'm gonna let this brew in my head for a little while.

regards, Coen


p.s. before anyone overlooks it: the above is NOT how to create galvanic isolation (if one should want to persue that). Your batteries and special 5V clock supplies will be connected to the USB board ground anyway.

Coen hi


I didn't get time to trace through the connections on Pauls PPA card so this is interesting. Certainly different to the way I have set up my "lash up" clocks. Most of the advice that I have seen in the past recommends to make sure that the clock live wire and the clock ground are connected to the clock signal input and the ground point next to the chip that is being fed the signal.

Personally I have always tried to connect the clock ground to the ground pay of one of the two resonant capacitors that get removed when the old crystal is removed.

I don’t like making comments on someone else’s implementation because  I really don’t know that much about this stuff and there could be good reasons for the implementation, so take this with a pinch of salt but my thoughts...

It seems that the Paul Pang card has a long return route for the clock signal ground current.  There would not need to be much low frequency noise in that ground loop to cause the bass problems that I experienced in my system at the week end.


My lash up clocks have their grounds isolated by the transformer, I think this is important for sound based on past experience with directly coupled clocks. Also the loop back the transformer secondary is kept as short as possibly by attaching both the clock signal and the ground close to the NEC chip where the old clock components were.

I have to say I'm really looing forwards to trying the two third party 24mhz clocks that have been ordered. I know them to have very performance and they are galvanicly isolated. there is quite an investment though so I'm sweating until they are in and performing.
 

Cheers Nick.

Hi

I just wanted to update on my experiments with the PP card.

As stated above I was not satisfied with the sound of the stock PP card. Assuming that noise is an issue and that the grounding scheme is a little odd I went to look for hidden potential in the card. As result I have tried and tested an alternative clock connection and different routings for the power supply of the card and clock board.

In chronological order I tried the following:

First I moved the leg of the transformer secondary from the clock board to the PCI card ground at the location of one of the removed capacitors (boy are these components small!). The whole idea is to vastly reduce the return path for currents generated in the secondary.
Soundwise this added some welcome body to the sound and better dynamics. Still the low end lacked power and it all sound a little 'rounded'. 

Then I moved the 5V/GND power supply from the PCIe molex directly to the clock board using a molex to SATA psu adapter cable, leaving the Paul Pang supply wires in place. The thought is to have a cleaner ground and 5V for the clock than for the USB cable. This is another big step in the right direction. The whole sound became louder and very musical, natural and organic. Perfect for classical, but unfortunately just not that suited for rock and the like.
Maybe important, but I did not modify the PC PSU molex, so in this setting there is no double 12V/GND routing anymore, only 5V/GND.

This inability to rock motivated me to disconnect the ground wire to the PCI-e card on the clock boards power supply. In the end there is an extra ground path created with this wire connected.
Without this wire only the 5V is connected, supplying to both the clock and the USB cable. Ground for the PCIe is provided by the motherboard.
This experiment was short lived, since now all naturalness and body was gone.

The next step was to disconnect both supplies from the clock board, now there is no 5V anymore. Now clock and PCIe card are fed by separate supplies from the PC PSU and no 5V is available on the USB cable.
This sounded better than the former, more dynamic and fresh. Closer listening learned however that cymbals sounded muted without body and that on crescendos the sound became thin and disorganized. Also, though I am not really good at this, there was no illusion of depth anymore.

FWIW reconnecting only the ground of the 5V to the PCIe, the roundness of the full connection returned.

Now as I feel a little tired with this card-in, card-out business, I switched on my lab supply and fed 5V/GND to the molex of the PCIe. Just as a hunch. Now we're talking! A rich dynamic sound, super musical, fantastic voices, tight bass and forever decaying sounds.

Now whats left to do is to swap the linear supply to the clock board and connect the PC PSU to the PCIe card molex.


Anyway all these experiments support my theories of grounding as well confirm findings of others. Some stuff I took away sofar:

1.  there is something with the 5V on the USB lines. It just sounds so much better with the 5V in place. This was already established in the USB cable thread.

2. The clock should have a SEPARATE 5V power supplies from the PC psu to the clock board and PCI-e card. This is the only way to be shure they have a common reference ground. I am inclined to state that only the 5V should be connected at the PCIe cards molex and not the ground, but I did not test that with an extra PSU wire.
Anyway a separate clock supply to avoid ground currents in (loops) in this apparently sensitive area is a great idea from the above findings. This is probably one of the reasons that the DEXA clocks work so well (if they do  ;)).

3. In retrospect the improvement in sound is amazing. For reference I refit my old USB3 card. No chance, a familiar sound but now mechanical, flat, harsh. Not that I ever noticed before! At this moment I can hardly imagine further improvements, but as we believe Nick and Paul, there is a vast potential still waiting!

I hope we can get to the bottom of this USB thing and address it in its root cause. For now this was a great learning experience.


regards, Coen

p.s.: please note that I have been talking about the PP v2 card!

edit: I noticed that my report missed some rationale. Now that only few have read it I have updated.

I just read it now Coen. Superb if you ask me.

Regards,
Peter

Coen, excellent stuff and quite timely too.

Great that you have given a second opinion about a lab supply onto the PPA card doing good things...I am glad we both agree on that point.  It is interesting the things you had to do to get it that way though.

I am confident enough to say that not only does the quality of the clock on the USB card matter, but the the quality of the power supply and ground loops also affect things, most likely because they affect the timing of the clock and the regularity at which it spews frames forth into the USB cable.

This all leaves me thinking about the clock implementation on the PPA card (and Nick and Pauls DEXA clocks).  I think we can do it better...the right clock on a USB board designed to better implement that clock (independent power circuits, layout of clock on board etc.) so that we can get away from wires between the upgrade clock board and the USB card as well as guarantee that the clock is as unimpeded as possible.  Almost certainly this would cost a fraction of the purchase price of a DEXA clock by itself and we should be able to get it to sound at least as good, or maybe even better.

Anthony 

Sooo, I have recently received my Silverstone USB3 card (the same model that Peter has had great success with - the SST-EC04-P) to compare with my PPAstudio V1 USB card. I finally put it in the XXHE at the beginning of the week to give it some hours and today I have been swapping in and out between them with and without my lab linear psu.

Interesting is all I can say...I prefer the Silverstone card.   More clarity and resolution especially noticeable in mids and highs.  By comparison my PPA card is a little smeared and slow which I can really notice on the strike of a piano key and the presentation of voices.  The most important thing for me though (as Peter would know) is that it seems as though the 'speed' or 'resolution' has improved along with clarity of the presentation.

The next step was to pull out the 5v molex connection from the XXHE SMPS and replace it with a 5v rail from my lab LPS.  Both cards improved along the lines of clarity and presence with a less harsh top end, but the Silverstone was still clearly different and clearly the one that I preferred.  The improvement in top-end resolution with the LPS is very good and the 'twangy' things in particular gained flavour and detail. 

With both the change to the Silverstone card and the LPS powering it seems as though a couple of 'veils' have been lifted which indicates to me that the Silverstone card is less noisy than the PPA card.  What features make it less noisy?  Well I don't know for sure.  It could be that the clock is closer to the speed of the usb clock in the NOS1 (correction calls), or that more care has been taken in the layout of the PCB itself or that less noisy components have been used or all of the above.  It could also be that as Coen has deducted with his V2 PPA card, that my V1 PPA card has grounding issues and that improvement is there for the taking.

Coen, I encourage you to post some photos of the mods to your V2 card so that I might apply them here as well and see if I can corroborate your findings.

Looking at the two usb cards, the layout of components is radically different but the NEC USB controller chips are from the same family (one supports two ports, the other four).  I can't help but think that the Silverstone is simply laid out in a more logical manner and this has something to do with what I hear.

Anthony

Hey Anthony,

You just managed to describe quite exactly what I perceive from the Silverstone, so I guess it is a general thing ?

What I noticed is that the Silverstone doesn't contain a single electrolytic (this was at some first glance, so maybe one is hidden somewhere). And 3 times less components (compared to that more general one I have and upon which' layout all seem to be based (but not the Silverstone)).

What I also didn't investigate further - but seem to have noticed with a 5 second look, is that there's no normal 24Mhz crystal on it. Could even be an active one (did I see 4 legs ? I think I did).

Peter

There is a 24MHz crystal near the Molex plug on the Silverstone.  It is only a small clock, similar in size to the ones found on the motherboard.

The Silverstone does seem to have its own general sound Peter, and I find that most interesting because until I had tried it I could not really detect a sound of the PPA card, but in hindsight I was hearing that card in everything.

Looking at that USB PCB schematic I emailed you a couple of weeks ago I think the layout of the Silverstone can be improved (eg. location of clock) plus a fair bit of stuff left off the PCB that we just don't need (such as the low power state circuitry - which we will never need).  Most of what is left after that is for the power supplies (3 voltages) which can be done better.  I am also wondering what can be gained by severing the power from the PCIe bus leaving only the data lines in operation and running on 100% external power.

Anthony

Let's say that this is what my special setup is about. :)
Its effect should be two folded ...


Well, I think this was my very first remark (in the forum) about this card, that it a. fairly (up to very) much presses its own nature of sound to all but b. that I could not "envision" that this would ever start to bother be as a flavour. This was right at day one of using it, and it still never happened (so never will by now).

Actually you need to do one thing only (but may require a better speaker) : focus on the size of cymbals.
Cymbals can easily be too large hence don't differentiate in size, or like it was with the start of Windows 8 - too small. But look now. You can now right away see all the different sizes and this is just caused by this card.
Or what I also said : you can not dedicate a frequency to its "flavour". It just allows for a sort of separation which should be named resolution but with the upside down effect : resolution enabling gaps. Too me this looks like "faster" though I see no "faster operation" possible anywhere in this domain.

Too much guessing at this time.
Peter

Here you are at the bottom of this post.

The ..75 picture shows that the x-former connection at the clock board is unaltered. The thick red en black wire come from the molex to sata adapter (the molex part has been ripped open to harvest the red +5v and black GND wire). The original PPA white/red power wires have been disconnected and are currently fed from the linear supply.

In the other picture ..76 you can see how I connected the x-former to the capacitor (horizontal on the aluminum block under the clock board with golden wires) and to the ground connected (outer) leg of C16.
It requires removal of the black synthetic and the x-former leg at the 330 (ohm resistor) position.

You can see that I am no craftsman and I warn you that it is tricky stuff to get the x-former connected to C16.

good luck!

regards, Coen

[I put in the smaller versions of the pictures as well because it could be more clear - Peter]

Hi Coen,

Thanks for those photos!  They really helped.  This week has seen the Silverstone USB card usurp the PPAcard as the preferred digital deliverer to the NOS1.  Spurred on by Coens experimentation I have taken the soldering iron to my V1 PPA card (Coens is V2) to see what would happen.

Firstly, I desoldered the power-in wires for the clock board (the red and silver twisted pair that run from the Molex to the clock board) and soldered in new wires to the clock board that will connect to a 5V supply (not via the molex plug).  I swapped the PPA card into the music pc did NOT connect the 5V molex, pressed play and....mweh...still not in the same league as the Silverstone...a colouration just as it was before.

Step 2.  I de-soldered the ground wire for the secondary? of the transformer from the clock board and, because the removed capacitor was inaccessible on my V1 card I connected it to the ground wire that originally ran from the molex plug to the clock board, but was now hanging free.  Again I put it in the music pc (without connecting anything to the molex plug) pressed play and...wait a minute...this is much better...on a par with the Silverstone, at least.

Well not quite.  I think that it is better than the Silverstone.  The resolution of the vocals, the cymbals, my-oh-my they are noticeably improved:  flesh, nuance, nice.  Coen, you are onto something here...very nice.

Of course I will do more listening over the coming days to make sure that I like what I hear, but it looks like the PPAcard is back in my good books.

See the photo below for my mods (following Coen of course).  Note the new (heavy) wires onto the yellow clock board and the silver wire from the molex plug connected to ground of the transformer.

Cheers,

Anthony 

[I put in the smaller version of the picture as well because it could be more clear - Peter]

Good work Anthony,

I'll return to the ppa card after the silberstone has settled and look what we can do further. I did not even try a separate supply for the clockboard yet.

Regards,  Coen

I ordered the Silverstone card too. To ensure that the most recent software is used I tried to download the Windows driver and the actual firmware. But there is a wrong download link for the firmware file.
The  correct address is http://www.silverstonetek.com/downloads/Driver/EC04-P_uDP720201_FW2020.rar
Playing music with the card after 24 hours burn in I must say that there is improvement - but only when connecting the 5V molex to a separate linear power supply!

Georg

Hi Georg,

Just a couple of questions:

- In the Silverstone site there is one driver for W8 (the one you mention) and a firmware update: look in this link for Accessories and EC04-P http://www.silverstonetek.com/download.php?area=usa (http://www.silverstonetek.com/download.php?area=usa)
Have you installed also the firmware? So far I´m using the driver that comes with the little cd inside the card pack, have you tried it? Maybe it is not for W8, I´m not sure, but it works...

- What´s the linear power supply you are using to power the card?

Thanks,
Juan

I realized that the driver I have installed with the Silverstone card is the version 3.0.23.0 (the one that came with the cd).

For the ones with this card, what´s the driver version you are using?

Juan

Hi Juan,

I installed the card today and will do listening tests in the next days.

My driver is the same as yours.

Regards,
Stanley

Thanks Stanley, I´ll be glad to hear from your listening tests

Cheers,
Juan

Hi Juan,

I did not install a driver specifically for the Silverstone card because it uses the same NEC USB Controller chip as my PPAstudio card, so there should be no need for a driver change.

Of course there may be a change with a different driver but I seriously doubt it.

Cheers,

Anthony

Ok, thanks Anthony, that´s fine if you are absolutely sure that both cards are using the same driver.

Btw, I´m not sure if you are using a linear ps with the Silverstone card, if so, what are differences you find vs this card powered by the pc power supply? (Sorry if you already have posted about it)

Cheers,
Juan

I am not absolutely sure both cards use the same driver (I have never looked) but they both use the same USB Controller Chip family so the drivers that use that chip _should_ be operationally the same.  Plus you can just plug them into w8 and the native usb drivers will work for both cards.

You could try the Silverstone with both drivers (and even no driver) if you like but I doubt that you will hear any difference.

The LPS that I am using is my cheap lab supply and as Peter would say, it helps "get out the Ssss's" and gives an improvement in clarity that is particularly noticeable in the mids and high frequencies.  I have all kinds of hair-brained ideas for removing noise from the the usb link that I will gradually work through because I think that there is a fair bit still to be gained.

Anthony

Yes I also find that sssss in the Silverstone and those hard highs are the bad part of the card, for the rest the sound is fantastic.

For when we will be able to enjoy your linear ps?. Maybe a small model for the USB3.0 card as the one you're using for the Silverstone would be fine to start. :)

What cable you are using to connect the Silverstone with the NOS1, an USB2.0 or an USB3.0 cable?

Juan

I'm using the cable that Peter sent out with the NOS1...USB2 I think.

The ATX LPS is coming along again after the Christmas/New Year break.  We have added some extra flexibility to the design which will cost a few more dollars but should also improve its performance.  I don't know when it will be ready but we are working on it.

Anthony

Anthony, Juan,

If this goes on a few posts more it will start to live its own life. I mean, the suggestion is put forward that I don't like the S'es (or something) about this card. Well, it is the opposite. I use the card *because* of it. Not S'es in particular, but the separation the card brings forward and what I describe as "more rough highs".

There is much more to this than what can be explained through words and possibly nobody will ever "see" what I'm after with this, nor might you be able to achieve it. But I'll try to give a few hints :

First of, take it that I am capable of more SPL in the highest regions than anyone else, unless you have the same mid-high horn as I use. For the tweeter this is 80W continuous power (over 300W peak). This is not to show off or anything, and it is also not about absolute qualities, but it IS about that I am really utilizing this power and that you can bet that if something is/goes wrong, it will express more easily than elsewhere and it will slamm you in the face.

What's already from quite many years ago (5 or so ?) is that a roughness in the higher regions (say 1000-2000Hz up to maybe 5000Hz) can be (or has to be) smoothened (filled up) with higher frequencies normally lacking. So, without this filling up you can perceived holes in the sound. This will be nothing strange or unusual, but notice that first all must be very speedy to perceive that in the first place; say that when the speed is not on par the sound will be more grey.

Side note : When I must listen to a paper cone driver for the higher regions this is totally unbearable. This is because paper is not fast enough and you will hear ... paper.

So when the speed is there, all is able to follow those 1K-2K frequencies, but because of the less energy in the way higher frequencies (5K and above) these holes appear. So, what I do is linearly increase the power to the tweeter so the higher frequencies present (in that same sound/music which implies the holes) now fills up those holes and sound gets smooth and how it would be in real life. In the mean time the highest regions of the tweeter are fed with close to 20dB more of energy; can be less and depends a but on other circumstances, like the operating system. Btw, I think it just have been the first W7 version where I explored this, because that was an OS with "holes" (SP1 solved that). And notice that W8 goes to a kind of extreme to the other side, where too much highs kills the cymbals; you know my stories about that.

You can already see that I'm operating in "illegal" areas.
But maybe not, because the energy of the high frequencies just *is* more low. Way more. This is because of microphones being less capable in that area and also because of how "digital" works. Well, never mind my (or the) reasons, but this is how I try to improve things, which normally are not even attacked by, say, loudspeaker manufacturers.
And let's not forget Fletcher-Munson curves, which is another reason. Ok ...

Without me changing those curves anymore, the sound of especially W8 is too silky. I can bring this down to the sort of fact that those holes are now overly filled, or better put in the realm of today : the output of the tweeter is too high.
Notice that it is not easy at all to "just" say that, because change a few dials in XXHighEnd and all goes to a very other direction. So, it is about what I perceive from it as a general characteristic and maybe it took those 5 years I apply the tweak to learn that the tweak itself is still OK. IOW, when I remove it, sound becomes quite "bad". Stuffed ears like.

What this Silverstone card does is bring back the holes but now to the extend it should. Maybe I shouldn't repeat myself, but it is about how "separation" is better, where "separation" actually is about resolution but at a somewhat lower frequency. So, on/off gets better of it (off is a hole). In the mean time, 1.186 is able to let the transients better "flow" and where previously a transient was a "one go bang", it now has a slope. This too is resolution, but of another kind and of the highest frequencies.

Still there ?

Although it wil be pure coincidence, what this card does is just right. I could add "to my system", but I don't want to say that because my system tries to do everything and all right and part of it is (thus) that a speaker should not show a flat frequency response curve.
Before we think that I now thus can not judge what will happen to your music reproduction - don't worry because so many other things are different, and this counts for everybody. For example, we could also say that what I am doing is not fair because of a 115dB sensitive speaker which you won't have. And if you only know how immensely much that does to speed ... If I turn this 115dB into 112dB it is already unlistenable for me because sound gets completely dull because of it.

Point could be that possibly I am better capable of judging this all (the higher frequencies) because if it goes wrong it goes wrong with me first. I mean, I just have way more output there and you can imagine that if e.g. an S is expressed wrongly in the base (say the software) over here this is amplified vastly and I will hear it before you ever can.
In the mean time, of course, you can wonder how my "S" won't get way more loud, but it does not work like that. So say the fundamental of an S is a fairly low frequency more square sound and that low frequency is not louder at all in my speaker. This is how the S won't get louder. However, because "square" means "high sine frequencies" it is exactly those higher frequencies needed to let develop the S and wonder oh wonder, how holes would exist with those lacking higher frequencies (of sufficient SPL). So because of the higher high frequency output my S is more smooth.

Got that a bit ?
This is all quite opposite from what intuitivity might tell you.

The Silverstone allows for better separation in the lower frequencies which sure makes the S more rough. Still this works for the better because in those holes now there, there's the opportunity to have higher frequencies sing. I know, this can't be explained by means of S-es but in the end you should be able to perceive them more real. Mind you, when these higher frequencies are there and a means of it is the Q3,4,5 = 1,1,1 setting. But what I told about a few weeks ago with cymbals, is the better example; while the more flattened grey sound is taken out and is turned into "holes", the singing of a ride cymbal comes forward, and right in the middle of smashing rock. This really is totally obvious and the card does it. And funnily enough, this does NOT need those higher frequencies to be louder because which cymbal could be represented well even on cassette tape ? the ride cymbal (hitting it in the middle as intended with a ride). So all that needs is this separation and this card does that.

Long story eh ? Well, it is meant to tell you that you should explicitly NOT try to smoothen that separation, but seek the solution elsewhere. Or just don't use the card of course.
But I think it is already clear from the reports so far that generally the card performs better, but you (or I) may wonder how, if in the mean time it is pereived harsh on the S-es. I don't mean "that is thus impossible" and I merely mean : so what is better then ?". So be careful because at least I never like to be subjective and better is only better when each of the technical elements is better. Each = all of them. And if one is not (could be an S) then this should express throughout though in other elements.

Ok, I'll stop here.
Peter

Peter, I've always liked the "Ssss's" from the Silverstone...that was the big difference between it and the PPA card...a more realistic and resolving reproduction of the higher frequencies...and I don't think that I have ever described them as harsh...I think they are a decent step forward. 

For whatever reason, the "Sssss's" are just better with a LPS into the Silverstone, and on that card I don't even know what the LPS powers.  Since I changed the grounding of the external clock board on the PPA card (thanks to Coen), and am powering the external clock on that card with my LPS I am getting an even better result than when I power the Silverstone with the LPS.

To further my experiments in this area, today I ordered a PCIe riser cable (http://www.ebay.com.au/itm/PCI-E-1X-Riser-PCI-Express-Card-Extender-Cable-Adapter-/250845534252?pt=AU_CablesConnectors&hash=item3a678f182c&_uhb=1) so that I can play around with cutting the power and grounds between the PCIe socket and the PCIe-USB card without damaging the cards themselves.  I intend to try the LPS to inject cleaner power into the cards and then if I can get that to work I will try a battery pack with a super low noise linear voltage regulator that I will build for the project.  Who knows where this will go but I hope to learn from all this before I think about messing with USB card clock mods, such as those DEXA clocks, because I want to exhaust every option before resorting to something like that.

On another side issue Peter, today I found a USB Controller Chip that will accept a 48MHz oscillator (480MHz is the USB frequency, so in theory this will be better amplified than a 24MHz crystal).  The chip is a little simpler to implement than the NEC chip on the Silverstone and PPA cards and seems to be used in military hardware.

Cheers,

Anthony

Anthony, you are funny ...

I just wanted to start a new topic with a suggestion of applying the Silverstone card to the PC without it's bracket touching the PC chassis. This, while I didn't even investigate whether the bracket is connected to the general ground of the card. Btw, it even could be that this is not the case, while the other cards do.

Anyway, now you come up with this riser cable, which exactly does what I wanted to propose (outside of other cutting wire opportunities).
Or remove the bracket ...

I feel this can make a great difference, and I guess you will agree with me right away ...

Regards,
Peter

Yes I agree, but I doubt that the bracket is connected to the ground of the PCIe-USB card, but you never know.

I was thinking about starting a new topic about these upcoming experiments with the USB card to see what (if anything) we need to do to improve noise (in theory - I assume that noise is what makes the difference) from the USB port of the pc.  Maybe you could start the thread off Peter with some reference links to the other threads that have been going in that general direction and then I will chime in with what I am hoping to trial.

Anthony

The best words I can use after reading your long post is: cryptic for me but interesting (I mean the part I'm able to understand).
My system is so different than yours, big horns vs little paper cones, that I'm afraid that your Ssssss is different than mine. However although I can't help further I try to learn from what you wrote.

Kind regards,
Juan

The Ppa card's bracket is connected to psu (and thus signal) ground. Seems good engeneering practice. I bet the silverstone's bracket is connected too.

Regards,Coen

Hi Coen,

I have just had a look at a USB board design that I have here (from Renesas) and you are right, it does seem as though the bracket is connected to both ground layers in that particular design.

Regards,

Anthony

Hi,
I made a combination of a new Silverstone card and ppa card. I replaced the Silverstone clock with the ppa clock.
No final conclusion, but as I hoped the SQ is somewere in the middle of the modified ppa and Silverstone.
The Silverstone freshness, but less Sssses. But all parts are brand new, still need some time to settle.

Remark: with loom and linear psu.
Regards, Arjan

Just reading the thread and was thinking the Same thing  an external xo on the Simple sliverstone Usb3 card

I've a ppa v2 which works best with no moleX connection and lifepo4 direct to clock board

When I first got the ppa usb card I thought it was only a little better than mobo rear port

Decent enough clocks can bet got at mouser Farnell/Newark etc

It seems power supply is everything
Lifepo4 here made a dramatic change

These clocks are extremely sensitive to power supply 
I suppose shunt or lifepo4 for clock supply would be optimal for this application

Arjan, I'm not a huge fan of the clocks that PPA uses but I'm very interested in how you connected the PPA transformer along with the PPA clock to the Silverstone card. I'm considering doing similar and if you have any pics, I'd really appreciate them.

Also, what was your final conclusion once things had run in a bit?

Cheers,
Crom