Power supply filter for computers

[juanpmar]

Jim Smith, the author of "Get Better Sound" a book and DVDs that I recommend to read because it has a lot of tips, exactly 202 tips, for installing and voicing the system and room (hey Scroobius, maybe there you could find the solution to your L shape room!) send by email new tips in what he calls "Quarter Notes" to the ones who bought his book. In the last one, Vol. 3 #2, he talks about a little filter that, in his opinion, helps to reduce RF contamination from the computer to the digital devices connected to the system.
This is his opinion about it:
"It’s a simple (but excellently engineered) power supply filter for computers. It was originally designed to prevent grunge from infecting the performance of ham radio stations.
I got it, put it on another circuit, and was amazed to hear my system improve so much. When things sound louder, even voices, that’s usually a sure sign that you just reduced background noise. Reduce background noise and you increase the effect of musical dynamics. Increase musical dynamics and increase your musical involvement."

The price: $106

Here is the link to the mentioned filter: http://arraysolutions.com/Products/nqnaclinefilter.htm

If there is any one that knows such a device please let us know.

Juan

[manisandher]

Hey Juan, interesting you should come up with this right now. This afternoon I had my 'noise sniffer' out to test a few things. And something occurred to me. My issue with noise is not that noise emanating from the computer and is possibly affecting the sound of the DAC - Peter assures us the NOS1 'takes care' of any noise coming down the USB line. No, my issue is that the computer's SMPS corrupts the same AC mains that feeds the other hifi components. This I can easily see with my noise sniffer. So this afternoon, I got out an old isolation transformer that I had sitting in my basement and connected it to my 'clean' mains. I used this to power one of my 'powerful' PCs with a SMPS. And you know what, this totally stops any noise from the SMPS entering the 'clean' mains (according to the noise sniffer anyway).

I'm happy! I can now use a 'proper' PC to run XX, without worrying about noisey mains, or potential ground loops by running the PC off another circuit.

It looks like the product you mention might work in a similar fashion. But looking at its cost, it's cheaper than most 500VA isolation transformers. Whether it's as effective, I'm not sure. One thing that I'm pretty certain of is that my 'noise sniffer' is pretty sensitive - it's specified to detect noise from 100Hz to 2MHz, and can detect a single dimmer switch 3 floors up in the house. The isolation transformer seems to stop the noise dead.

Mani.

[juanpmar]

Hi Mani, great job testing your system with the "noise sniffer". I don´t have such a sniffer so I don´t know if the mains are polluted by the computer or not. Anyway just for precaution I use a power conditioner built with two isolated big 500va transformers with some other filters inside, this power conditioner is connected to the mains with a Foundation Research LS2 cable that also has a kind of filter. I connect both the dac and the computer to this filter but each of them to a different transformer that as I say are isolated from eachother. The PC is connected to the conditioner also with another Foundation Research power cable, for the dac I use a Grover Huffman power cord with no filter at all.
I think that probably is enough filtering, maybe too much, I don´t know... Besides the system uses a dedicated power circuit different than the one for domestic uses.
Some time in the next days I´ll try, just to see if I notice some improvement, to put the computer completely outside from the dedicated circuit where the system resides.

Here there is some kind of sceptic information about different conditioners, filters and cables: http://www.epanorama.net/phpBB3/viewtopic.php?f=14&t=133293

Juan

[cfmsp]

Here is the link to the mentioned filter: http://arraysolutions.com/Products/nqnaclinefilter.htm

If there is any one that knows such a device please let us know.

Juan,

I use a custom version of this filter between my computer and AC circuit.  A fellow computer audiophile asked Ed Wetherhold to add some additional filtering to deal with frequencies not usually addressed by typical filters.

You might want to ask Ed if he would consider another run?

As I recall, the price increase for the add'l filtering was nominal, although the box was twice as big.

clay

[juanpmar]

Thank you Clay, what´s your opinion about the W3NQN-7 filter?. Have you compared it to other filters or power conditioners?.

Best regards, Juan

[cfmsp]

Thank you Clay, what´s your opinion about the W3NQN-7 filter?. Have you compared it to other filters or power conditioners?.

Juan,
I think any of the Array Solutions filters are likely a bargain, but I've only used the custom model, designed to operate at a higher frequency than normal audiophile filters.

The filter definitely improved the sound of my system when used between computer and AC, but I've not compared it head to head to other filters.

I also use Audience Adept AR1Ps (which I bought used, as I don't consider them great value when purchased new), in line with the Array Solutions box

I've also heard great things about PS Audio filters like the Ultimate Outlet and it's replacement the Duet, which is supposed to be even better.  Note: I recently picked up a B stock Duet from Parts Connexion at a great price, but haven't listened to it yet.

These are the boxes I use for the computer side of the setup.

If money is no object, perhaps the Ayre LX-5e would be a consideration.  Charles Hansen knows a thing or two about isolation & filtration.

Note: I never plug anything else into the same filter as a computer, or the same duplex, for that matter.

[Scroobius]

Hi Juan - I like the look of the rf filter very nice & properly engineered not like the half baked cable solutions that hifi gadget suppliers sell. The book and DVD's from Jim Smith looks very interesting and I think I will be buying them - not sure if I can solve my room issues without bricks, mortar and a trowel but maybe there are other things I can do to help so watch this space. Nice recommendation.

 

[stoneman]

I read Jim's "Get Better Sound" newsletter too and it got me thinking about better PSUs for PCs.

Has anyone investigated this please?

I have a Hush Technologies PC which I believe is actually based on a laptop - it has an external PSU which is generic looking and feeds a thin cable into a 3-4mm dia. plug in the back of the case.

Is it possible to (and would there be any sonic advantage in) improving it?

regards
Andy

[juanpmar]

Hi Andy,

I can think on two ways to improve your sound:

- Changing the cable to a better one with or without filter, that depends on the power supply specifications of your computer

- Plug in the computer to a diferent circuit than the one where the sound system is. To do that you need to have a specific circuit for your sound system different than the one of the home. This is the best solution imho, even if that´s the only thing you do, you are going to get better sound for sure.

Please put the details of your system configuration in your profile so we can help you in a better way.

Regards, Juan

[PeterSt]

Plug in the computer to a diferent circuit than the rest of the sound system. To do that you need to have a specific circuit for your sound system different than the one of the home. This is the best solution imho, even if that´s the only thing you do, you are going to get better sound for sure.

Don't count on this too much !

Sound will change alright, but try to interpret it for its real merits.
If I do this, it only brings (measureable) misery. But, I am talking about dedicated earth pins for the both circuits. This matters.

Peter

[juanpmar]

But, I am talking about dedicated earth pins for the both circuits. This matters.

Well, if you live in a home with your own garden etc maybe you can have two different earth pins but I live in downtown Madrid in a community building and there is no way (as far as I know) to put another new earth pin only for me.
What I can say is that even with the same earth pin but having a different circuit coming from different circuit breakers the sound is not only different (maybe) but for sure better, better for my taste, which of course is subjective because I can´t measure it.

Regards, Juan

[PeterSt]

I meant : when you have separate earth pins things get *worse* ...

[juanpmar]

Hi Peter,

I meant : when you have separate earth pins things get *worse* ...

Sorry, I understood the opposite. Does it means that having the computer in other different circuit than the sound system but with the same earth is ok?

Regards, Juan

[PeterSt]

"OK" I don't know, but not extra-bad I think.

Peter