[ngiachin]

Quick question...I was wondering if anyone know of any tips/trips for reducing interference inside a pc case. I am building a PC to use as transport and probably DVD player/video scaler. I would like to make it as "quiet" as I can. I am using a Antec Aria case, so I do not have a ton of room. Can you wrap the cards in any type of foil or emi/rfi paper?

Second question....

I am using this setup in a pretty high end setup. I am using two modded 4channel adcom 2354 amps to quadamp a pair of Linkwitz Orion speakers (best speaker ever made?...we'll soon see). I am alittle curious as to using the htpc to feed direct to the amps. I have always been told how terrible digital domain volume control is, but then i've heard opposite arguements. Any opinions on this? Right now I have a little dared 2000a tube pre-amp that I can experiment with, but I was wondering if anyone had any additioanl experience.

Third question...

Any other advice anyone could provide me would be well appreciated. this system is definately costing a boatload of cash, but I am trying to use as many unconventional methods as I can...it is a bit of an experiment. Thanks alot.

Nik

 

[VitaminJosh]

Quote:

Originally Posted by ngiachin Quick question...I was wondering if anyone know of any tips/trips for reducing interference inside a pc case. I am building a PC to use as transport and probably DVD player/video scaler. I would like to make it as "quiet" as I can. I am using a Antec Aria case, so I do not have a ton of room. Can you wrap the cards in any type of foil or emi/rfi paper?

Tin foil works somewhat for dampening some of those noises. Not aluminum foil, I mean real tin. Aluminum foil would have to be crazy thick to notice any difference. Why even bother though? Most good audio cards have pretty good filtering already. If it really bothers you that much, why not go for a sound card that has all of it's electronics external to your PC?

 

[ngiachin]

Josh,
Well, it does not really bother me, I am just trying to gain some expert advice on an area I am not very experienced in. If there were little tricks or tips, I figured you guys would know. As far as an external solution...I don't want to spend much more than 300 on a card and was originally looking at a 1212m w/ opamp and class-a bias mods. Any other suggestions?

 

[Mr.Radar]

The EMU 1212m has some of the best power filtering of all the soundcards on the market today and you definately can't go wrong with it.

 

[shimage]

Quote:

Originally Posted by VitaminJosh Tin foil works somewhat for dampening some of those noises. Not aluminum foil, I mean real tin. Aluminum foil would have to be crazy thick to notice any difference. Why even bother though? Most good audio cards have pretty good filtering already. If it really bothers you that much, why not go for a sound card that has all of it's electronics external to your PC?

Faraday cages work by reflecting EM fields. The ideal faraday cage is a grounded, perfectly conducting box. As such, I don't understand why you'd want to use tin. Aluminum is one of the best conductors on earth, so it doesn't make sense to me to use anything but aluminum foil.

I read somewhere on this forum instructions on how to build a conducting shield for one's soundcard (you want to make sure you don't short anything that shouldn't be shorted). Elsewhere in that thread, I think the fellow said that it didn't help at all...

 

[ngiachin]

Really? Interesting...I am just going to build up this machine normal and see where we are...thanks for the input.

Quote:

Originally Posted by shimage Faraday cages work by reflecting EM fields. The ideal faraday cage is a grounded, perfectly conducting box. As such, I don't understand why you'd want to use tin. Aluminum is one of the best conductors on earth, so it doesn't make sense to me to use anything but aluminum foil. I read somewhere on this forum instructions on how to build a conducting shield for one's soundcard (you want to make sure you don't short anything that shouldn't be shorted). Elsewhere in that thread, I think the fellow said that it didn't help at all...

 

[VitaminJosh]

Quote:

Originally Posted by shimage Faraday cages work by reflecting EM fields. The ideal faraday cage is a grounded, perfectly conducting box. As such, I don't understand why you'd want to use tin. Aluminum is one of the best conductors on earth, so it doesn't make sense to me to use anything but aluminum foil. I read somewhere on this forum instructions on how to build a conducting shield for one's soundcard (you want to make sure you don't short anything that shouldn't be shorted). Elsewhere in that thread, I think the fellow said that it didn't help at all...

The person probably found no difference because the noise was leaking back into the system through the ground plane. I wasn't refering to making a conductive shell to reflect, I was just talking about a standard grounded to the chasis ghetto-as-hell cardboard/foil/paper towel approach

If you're going to do a Faraday Cage for a sound card, I think you'd have to modify your motherboard with higher quality components so nothing could leak into the PCI bus. Then what about the power rails? So to cover the wavelength we'd be dealing with a loose aluminum mesh, followed by thick iron housing, and... Oh nevermind. Might as well bust out the conductive concrete!

 

[Glassman]

Quote:

Originally Posted by Mr.Radar The EMU 1212m has some of the best power filtering of all the soundcards on the market today and you definately can't go wrong with it.

based on what? can you elaborate a bit? I see no special regarding supply filtering on E-MU.. rather basic I'd say..

 

[shimage]

Quote:

Originally Posted by VitaminJosh <snip>I was just talking about a standard grounded to the chasis ghetto-as-hell cardboard/foil/paper towel approach </snip>

I was also referring to a grounded cardboard-foil contraption, so how is what you were referring to different? What exactly is it supposed to be doing, and what particular properties of tin makes it an ideal material? I don't know much about (complicated) circuits, so I'm just curious.

 

[Mr.Radar]

Quote:

Originally Posted by Glassman based on what? can you elaborate a bit? I see no special regarding supply filtering on E-MU.. rather basic I'd say..

Notice I said of all the cards on the market today. Many cards, even high end ones, don't use ANY power filtering at all (like the RME HDSP 9632). Compared to real power conditioning it's not very good but it's better than nothing.

 

[Glassman]

I can't see any filtering of +/- 12V opamp supply for example.. other voltages are regulated by 1117 and 7805 regulators as usuall on almost any other soundcard..

 

[Mr.Radar]

Computer power supplies are switching power supplies that output really dirty power (compared to linear power supplies used in dedicated audio equipment) not to mention all the motors and ICs used in a computer. Most cards only use a few caps if anything to reduce the noise on the power lines while the EMU (according to Iron_Dreamer) has decnet power filtering that does make a difference in sound quality. If you want to know more PM Iron_Dreamer.

 

[VitaminJosh]

Quote:

Originally Posted by shimage I was also referring to a grounded cardboard-foil contraption, so how is what you were referring to different? What exactly is it supposed to be doing, and what particular properties of tin makes it an ideal material? I don't know much about (complicated) circuits, so I'm just curious.

A Faraday Cage is closed on all ends, and inside of your computer with a PCI card that's near impossible to do. There are a few reasons that tin would be better for this application. Skin-effect. Aluminum foil is up to 98% pure, so I agree to you it makes a great conductor; but what about leakage? EMI causes a magnetic field in the metal because there is a current flowing through it, which in turn would create the audio disturbance. The less conductive your shield, the less that is going to flow through it. Tin foil is much more dense than aluminum, and will act like a dampener rather than an antenna. I ran an experiment with my Sony SRF-83 before replying to this post - it took me 4 layers of aluminum foil wrapped around it before I lost tune to a station and it turned into fuzz. It took me 1 layer of tin foil. Just to make sure it wasn't the qualities of the tin filtering lower signals than the aluminum; I then tried it on my cell phone. ATTWS GSM, Nokia 6800. It still took more aluminum than tin foil. I heard the disconnect after 6 coverage sheets for aluminum, and 2 for tin. (it was on speaker phone with a locked keypad dialed into my home line)

 

[Adriel]

ERS Sheets. Adhesive version is $30/sheet. Works well on digital chips and power supplies.

 

[Glassman]

Quote:

Originally Posted by Mr.Radar Computer power supplies are switching power supplies that output really dirty power (compared to linear power supplies used in dedicated audio equipment) not to mention all the motors and ICs used in a computer. Most cards only use a few caps if anything to reduce the noise on the power lines while the EMU (according to Iron_Dreamer) has decnet power filtering that does make a difference in sound quality. If you want to know more PM Iron_Dreamer.

you're just claiming what you heard from Iron, I thought so.. like I said, till now I saw nothing extraordinary regarding supply treatment on my 1212m.. I'm gonna improve upon it of course..