Does Improving PC PSU and Reducing PC EMI/RFI Improve SQ?

[astacus21]

you can try isolate the power pinouts of pci bus and make a psu for your soundcard. Take a look at this:
http://www.interfacebus.com/Design_PCI_Pinout.html

[earflappin]

Hi Peter, any updates yet on your experimentation with different power supplies for your new StarTech outboard PCI expansion chassis?  i'm living vicariously through you on this ya know.....   

[PeterSt]

I planned to spend yesterday on this, but instead got involved in DAC stuff. Today I was out, and now it will be somewhere this week I'm afraid. Not before Wednesday.

I am as curious as you, but it really takes some time to set it all up, switch PSUs and stuff.

[PeterSt]

But before I forget to tell :

Yesterday I got the projector screen out of the ceiling, and it has got a kind of high current (surging) motor;
Getting it down was not a problem, but stopping it when it was down, was. The music PC rebooted. Ok, it was time to stop listening anyway (movie time), but not quite intentional.

All will imply that at stopping the motor a power peak will have occurred, and I guess the 0,000001nF capacitors in the (switching) PSU couldn't buffer the peak.

I may have told before that the 12V power connection to the board goes via a kind of loosish connector (coming from the brick), and it already happened that just touching the power cable a bit, caused a bick crack through the loud speakers.
Notice that the box is never to be powered down when the PC is running, nor should it be powered up then (it is not hot pluggable).

So, that we already know.
Peter

[PeterSt]

Back again on this one ... but I guess it will be my last post about it.

48 hours ago I brought the lot over to a friend's W7 machine;

The stereo was at a longer distance from the PC, so we started with a longer cable. Nothing. (this worked on my Vista)
A shorter cable - Nothing.
A short cable - bingo.
Next moved the PC towards the stereo, but ... nothing.
Huh ?
Many hours later I went back home without result.
Back home though ... nothing.
Huh ?
A driver had disappeared from my PC too, suddenly, but yesterday I found which (system, mobo) driver that was, downloaded that and restored it, but ... nothing.
Many many hours of attempts later, I just rebuilt everything as how it was before the expansion box, and now I have sound again.

In the mean time 48 hours no response from the supplier.

To me it looks like the W7 attempts have changed something to or the PCIe board, or the remote board. I can't tell. Anyway this obvioudly shouldn't happen. Something can just be (hardware) broken as well. Again, I can't tell.
Notice that PCI extension is a strange thing to begin with, and possibly this solution is just too cheap. If 300 euro is cheap ... but anyway, down the drain for me.

If I ever get an answer from the supplier I'll let you know. Especially if it is a stupid answer.

Prrrt
Peter

[earflappin]

Sorry to hear that!  In your experiment were you using the ExpressCard in a laptop or were you using a desk-top PC?  Dang, I was looking forward to hearing about the power supply experimentation.....   

[PeterSt]

The desktop.

As a kind of "last resort and prove what is going on" I wanted to try the ExpressCard, but in such a situation your laptop has to support that. The one I have here, sadly, does not. And I didn't hunt for a converter (which does exist (PCCard (PCMCIA II) to ExpressCard).

Well, I can only say I am sorry.

[earflappin]

No worries as the Aussies say....    Not your fault...you were just another victim of Murphy's Law....anything that can go wrong, will go wrong, and usually when least expected....   

Hopefully StarTech tech support can fix the issue.  Otherwise you should demand a full refund.

[Nick]

Hi,
Just caught this thread on PCI power supplies and though I would post my experiences generally on PC power supply and power mods to PCI cards. Sorry for the long post, got a bit carried away but I hope it adds to the experience out there.


PC switched mode supplies seem to be bad news for audio. My experience is that different supplies give much better results than others but I got fed up with the hit and miss approach to buying ATx supplies on the chance they would improve sound quality so I ended up going down a different route....

I currently use a ATx supply (selected for low noise levels) for my CPU and mother board. For everything else the systems has external (outside the PC) linear laboratory bench power supplies (6 in total) on;

1) All cooling fans (nasty things for Sound Quality)

2) Hard drive (both 5v and 12v supplies) I only have one powered up while playing music

3) PCI USB card. The USB PCI card is where it gets more interesting. I have cut the supplies from the PC’s PCI bus to the card (got the PCI Bus standard pin from out on Wikipedia). I now have 3 high quality +5v and +3v linear supplies (Audiocom 2 X Q-Powers and 1 Invisius supply) physically on to the USB card. One supply runs the clock area of the card, one the main USB chipset on the card (see USB chip set note below) and the last seems to run the USB output drivers. In addition all of the bypass capacitors on the USB board have been upgraded for N Type Black Gates and OsCons. I started by powering the separate piggy back supplies from the PCs ATx supply but they now run from an external smoothed lab 12V lab supply outside the PC.

4) Not done this yet – but I want to mod an old Audiocom Superclock 3 that I have to 48mhz (common USB card frequency) to upgrade the PCI card USB clock. I expect this to be very effective from past experience.


The replacement of the USB PCI card bypass capacitors is very easy to do and easily audible - well worth the effort (even still running on the ATx powered PCI bus motherboard 5v and 3v rails). Cutting the PCI 3v and 5v rails on the USB card and running from the piggy back linear supplies makes a bigger difference (really cuts down on digital hash), using the external 12v lab supply better makes it better again.
Although my experience is with PCI USB cards this stuff will work on sound cards, if you have digital audio processing or particularly analogue audio functions (eg UDB, FireWire, SPDIF, Soundcard DACs, line level OP-Amp outputs etc) on your PCI board I would expect even bigger changes to sound with similar power supply mods.

Note on USB Chipsets - For other folks using PCI USB this may be useful in helping to home in on good sounding USB boards. My experience of on mother board USB has been poor with very little chance for upgrade. On the USB PCI card front I have tried most of the USB chipsets and a lot of boards for sound quality including NEC, VIA, OPTI samples. I have also tried PCI Express USB cards but most of these are just regular PCI USB cards (usually with an NEC chip set) with a PCI Express to PCI bus bridge chip on the card. By far the best cards for me have been normal PCI USB cards with the NVidia chipset, a much better sound and responds better of all to the power mods described above. The NVidia chipset takes some getting hold of but Startech USB cards still ship with NVidia. If anyone knows of any pro audio targeted cards I would be very interested.


Downstream outside the PC the power supply obsession continues I am using an M-Audio Transit for SPDIF conversion into my Audio Note DAC. The Transit card currently runs 6 separate supplies on the board feeding most of the important vcc rails on each of the 3 chips in the Transit card. These supplies are in turn powered by a Lab bench supply. In addition the Transit 6Mhz clock has been upgraded with a modified AudioCom Superclock 4 this also has its an additional separate AudioCom Invisius  +12v supply.
For my setup the power supply mods above have taken sound quality from a very high quality digital audio system into the realms of high quality analogue (vinal) playback. Well worth the time and effort.


Regards,
Nick.


Ps Peter, I have to say XX 09y-4 is absolutely stunning, thanks for a fantastic player,

[PeterSt]

Wow Nick, that really "sounds" fantastic !
Might you run into some ever made picture ... it should look impressive ...
But you don't need to of course.

I guess it just is all about this.
Peter

[earflappin]

Nick, thanks so much for your post!  This was exactly the kind of information I was looking for....someone who had actually run this type of experiment.  I use a Lynx AES16 PCI card that outputs AES/EBU to my DAC and want to try what you've done.  Can you provide a link to the site where you bought your power supplies?  How loud are the fans and are there any power supply alternatives which run silent?  Also, some pictures would be greatly appreciated when you have time!

Thanks again.  Greatly appreciated. 

[PeterSt]

How loud are the fans

Fans ? ... well. Maybe linear power supplies with fans exist hahaha

Only kidding.

[leifchristensen]

very nice comments Nick
just up my alley and something I´ll try in my own setup
what single psu update would you give first priority?
I now use asus p5k-e mobo spdif output x-former isolated to my buffalo dac but plan to run mobo usb to hiface-I2S to buffalo I2s input
best
Leif

[AUDIODIDAKT]

Just caught this thread on PCI power supplies and though I would post my experiences generally on PC power supply and power mods to PCI cards. Sorry for the long post, got a bit carried away but I hope it adds to the experience out there.

This is nice info Nick, Thnx for sharing your experience

What I'am interessed about is this:
I can only imagine what the difference would be when powering your soundcard seperatly, this is pretty important IMO. (also shielding and galvanic isolation ofcourse)
This is a must !

But would taking it step FURTHER, as in give the MoBo a seperate PSU plan, result in better SQ ?
Is this because of stable powering or reducing the EMI/RFI ?
And what should need a seperate psu: RAM, CPU, NB, SB, SSD or all?? and why ?
(hdd's, vga and fans (maybe 1 case fan in there) should already been removed)

And how about booting (start-up)(+12V line I belief is the one being switched)?

Very interesting discussion btw.

Roy

My mobo has like 7x +12V, 4x or more +5V and some +3,3V (what needs +3,3V ?)

[leifchristensen]

3,3 vdc is for harddiscs
best
Leif