[caudio]

It is said that PC can NOT provide sound as good as CD player because the power from PC switch power supply is dirty.

And the only way to remove the noise is to use the LC circuit as filter.

Does any one used the choke(s) between the switch power and the mother board as the filter(s)?

 

[caudio]

To audio, we actually are hearing the power. The source; amp are just the switches to control the output of the power. Therefore the power is some what critical. Using choke is the only way to remove the noise from the PC switch power supply.

If not understand what is a choke, see this:

 

[leeperry]

don't believe everything "they" say....a quality PSU is far from being as crappy as most ppl think.

that's a Seasonic S12-II 500 Watts :
http://www.canardpc.com/img/dossier/.../s12ii-04b.jpg
http://www.canardpc.com/img/dossier/.../s12ii-03b.jpg

and quality soundcards carry "sanyo os"-like caps to clean up the incoming current...like the Asus STX/ST do.

 

[lxxl]

There are many quality PSU that provide clean power. Few brands off my head are Corsair, Seasonic and Silverstone. Check the rating system in some of the online stores and you'd know which is good.

Personally I have 2 Corsair PSU.

 

[Kursah]

I have a Corsair HX520 and PC Power and Cooling Silencer 750 Quad, both are great and from what I have heard provide clean power. They are both 80%+ efficient too. There are definately a few good quality PSU suppliers, but you will pay more for it, to me it's worth it overall.

 

[mattpwill]

I use an Antec Signature 650 PSU (the best you can buy for power quality, in theory), and tried powering my Tripath TA2020 amp (with its line-in unconnected) from it (the +12V and ground on its own molex cable) while it simultaneously powers the PC. There is to my disappointment a lot of noise made through the amp whenever the PC is processing something. The same noises that old laptops give off from their onboard sound. I tried everything to diagnose (undervolting, underclocking, disconnecting all components possible, checking connections), but nothing removed the noise. This lesson taught me the importance of power filtering. It gets the "crosstalk" from the rest of the components connected to the PSU

Does power filtering affect sound quality in any way? I assume that sound cards need more complex power filtering than an amp with its own toroidal supply?

 

[leeperry]

the STX has 2 decoupling Sanyo-OS caps to filter noise out.

and SI actually made an internal card w/ a Tripath chip, maybe you can look at its PCB layout : sonic tio board - Google Image Search

I really like the idea of this board, too bad it's EOL..and the STX/ST soundcards are dead silent! but I guess not everyone is as skilled Asus when it comes to PCB shielding...so maybe it's a good thing that this card is unavailable after all

 

[Uncle Erik]

That would only remedy one of the problems with a switching power supply.

The bigger problem, in my opinion, is the massive amount of RFI (radio frequency interference) that a switching power supply throws off. It's like having a little radio station inside your computer that's generating static that's picked up by wires and components, just like an antenna, then feeding it into the sound.

Whether or not the AC is clean is an entirely different matter.

The only way around this is with substantial shielding - which can be ad difficult as waterproofing the computer. RFI reflects, bounces around and gets in through the tiniest of openings or can even be conducted by shielding.

Otherwise, you have to use a linear power supply. You can, of course, but it'll be heavy, complex and expensive.

 

[Philski]

I have been experiencing the same problems, a persistent electronic static sound that's always present in the background (unless the volume is really cranked up). After a lot of faffing around, I found that the noise disappeared completely by disconnecting my laptop from the mains. Duh.

Sooo... I need a really high quality PSU. Leaving the laptop to run on batteries isn't really an option as the Toshiba Satellite I am using has a woefully poor battery life (<2 hours). I have looked at Corsair, Antec, and the others recommended here, problem is that the most they will output is 12v, and my laptop needs 19v (at least that's the output stated on the transformer). Does anyone have any ideas about how to get around this, and whether there are any quality PSUs on the market aimed specifically at laptops, or at least are able to supply 19v?

 

[leeperry]

yes, I know exactly what you mean. I get it on the STX on the HP out if I select the RCA out in the drivers...but as soon as I select the HP out, it goes away.

I also get it on the mobo Realtek chip...I think the only ways to overcome this issue is to run on batteries OR to have a properly shielded soundcard PCB. any PC PSU will still be a switching design.