So i replaced my PSU and my PC sounds much better.

[DJNUBZ]

I just wanted to tell you guys about an upgrade I did today. I replaced my cheap cpu power supply with a Seasonic X-400 fanless PS. Not only is my PC almost silent now, my Xonar ST sounds much better. This could be because my old PS was an underpowered generic piece of junk but it could also be because of the low (<20mv) ripple from the PS. I was going to build a linear PS for the card but now I wonder if it is really needed. Is it stilll worth building? Is there any way to get the ripple smaller?Seasonic X-400 Fanless PSU | silentpcreview.com

[geraldfryjr]

I have had the very same idea of building a linear supply to power the computers in my system.

At first I had quite a few ground loop problems especialy when hooking up the sound card to my mixer.

Most all of those issues have been resolved by a new power cable configuration.

However I run my amplifiers wide open and the noise floor of all of my equipment is at least -100db or better.

I get a 60hz residual noise has high as -60db measured in the system using an FFT program and can be heard in the speakers when they should be dead silent.

It is not loud enough to be annoying it just annoys me that it is there,However it is high enough to be to be a problem in final master recordings.

Although I haven't yet traced this source down ,I believe it stems from the computer power supply's,possibily on the ground side.

Before I had solved the ground loop issues, It was very evident that there was substantial noise being introduced when the computers were on and disapeared when they were off.

They also disappeared when I lifted the ground on the mixer or the computer and I wasn't about to run the stuff with that type of configuration.

So, I then tore it all apart and started over.

I still have issues of noise getting in the cables that feed various T.V.'s and video monitors that goes away when the computers are shut down.

Right I am using two computers.

One is a dell dimension 4700 and has a matrox video digitizer card and seems not to be effected and causes very little noise if any.

The other one is a Dell Dimension 2400 and has a tuner card in it for video and it is this one that is creating havoc on the system and it makes no difference if the side panel is on or not.

I have thought about adding more filtering to supply outputs and line inputs,but I haven't gotten that far yet.
I'm not about to go out spend big bucks on a supply if the results are going to be marginal.

I think a linear supply would be super in this type of situation.
I still have the power supply's from a couple of mainframe computers (DEC and NCR) that I tore apart.
I have been seriously think of using those in this type of appilcation.

I'm sure that a Linear supply could be built for less than what some switching supply's of equivilent power rating are selling for.

The only drawback of course is the size and getting it to fit in side of your average computer case.
This might be an issue for some ,but, not me. jer

[DJNUBZ]

I had a Dell Dimension that had the PSU go bad a few years ago. The problem I ran into was that Dell uses a proprietary plug on their PSU and motherboards so you have to use their parts. I am not sure if your models are the same way but you might want to look at that. Do you have an O-scope? If so you can see how much noise you are getting from your power supply.

If you were to go with a linear PS you would be better off building it into it's own case. Just remember that you have to have very good regulation because computers don't like fluctuating voltage.

If you can use an aftermarket power supply I recommend you try the Seasonic I posted. Its low ripple and fanless design might be perfect for the work you are doing. If it doesn't fix your problem you can always return it.

[geraldfryjr]

Yes I do have an O-scope that is how I found all the noise on the ground side.

Right now all is quiet since I rerouted all of the cabling except for some 60hz coming from some where.

I just haven't taken the time to trace it down yet as there is at least a mile of cabling just on the audio side alone.

I will look into the seasonic power supplies as I have read many good test reports on them.

My little Dell's use the normal AT type power supply connectors.
My Dell 1600 SC server has a dead mother board with a brand new power supply but I am not sure if it uses the the standard or proprietary power supply connector.
I'll have to get it out again and check.

My DEC supply has a 1500va transformer and is compleat with regulators although I would have to put it back together and design a 3.3v regulator for it.
I was planning its use for a monster class a amplifier,but I have several large transformers that I can use aswell.

It would be nice to have all (several) the computers running on a single supply in there own rack with no fans running and water cooled with the cooling unit in a seperate location other than main studio and sound room because of the noise.
It is not that bad ,but it is a different situation when you are recording instruments.
Those are my future plans anyway.

Right now I am getting as much 100mv of RF noise on some peices of equipment an less on others.
Although this is fairly normal, but I know from past experience that this can be virtualy eliminated.
I know I desperately need a new ground rod and that may be the cause of the whole problem.
Right now I can not use any tuners while the computers are on. jer

[qusp]

if you dont sort your ground issues, all the quiet power in the world will not save your recordings. balanced ins and outs will help, but likely there will still be residual hum

[geraldfryjr]

Oh yes,Now that it is summer time I ill install a new ground system and the cool thing is that I live on a lake and that will make for a very efficient and simple ground system. jer

[KlipschKid]

Hi,

I have a Silverstone ST40NF 400W fanless smps psu in my desktop. It's very similar to the Seasonic.

I have an AMB Sigma11 50W linear psu in an Intel Atom based music PC.

Definitely the AMB psu is better, but with all the noise pollution from the mobo/PC components, personally I wouldn't bother building a 400W linear supply for my desktop unless I had run out of other projects to keep me busy. And even then I might think my time would be better spent hacking the components on the mobo - better caps, oscillators, regulators, etc.

But that's me.

[syklab]

Hi Klipschkid,
Would you mind to give more detail on the AMB Sigma11 linear PSU? Is there any DC-DC convetor in your Atom PC ? How to eliminate that ?I am planing to build a E350 based musice PC and think about how to improve the PSU.

Thanks

[multi]

Hi
I am using my computer as a CD player. What is the best sound card?
How does a computer with a good sound card compare to a CD Player.
I have friends who have spent 20thousand + dollars on CD players and they don't sound that much better to me.
Phil

[KlipschKid]

Originally Posted by syklab

Hi Klipschkid,
Would you mind to give more detail on the AMB Sigma11 linear PSU? Is there any DC-DC convetor in your Atom PC ? How to eliminate that ?I am planing to build a E350 based musice PC and think about how to improve the PSU.

Thanks

Hi,

The AMB psu is DIY - and very good indeed - read about it here :

The &sigma;11 Regulated Power Supply

I used 3x 4700uF caps for C5 to keep ripple as low as possible under a 2 amp load with peaks up to about 3. I use a 60VA trans. It gets hot. I also used a large offboard heatsink - something around the same volume as the populated pcb. I'll post a photo later if you want so you get an idea of the space needed.

The Intel board uses about 15W and I estimate the Onkyo card to consume about 7W more. I sometimes need to connect a notebook dvd drive too and that adds another 5W or so.

I think the E350 uses a lot more juice, so I'm not sure it's a good choice for a linear psu. You'll need a large transformer and it'll get hot, plus you'll need some large heatsinks. Space and cooling might become serious issues.

AFAIK every mobo uses dc converters - and why not when mobos generally expect to get noisy smps power anyway. Plus there are billions of transistors constantly switching states at high frequencies which is gonna generate large amounts of noise.

I'd love to hack the mobo and improve the power but I'm not sure the huge effort would reap much in reward. I've done some soundcards and found them really hard to desolder. So I figured the simplest way to improve power was to use the Sigma11 so the source psu is as good as it can be, but to do this I needed an ultra-low power mobo; Intel D945gsejt.

cheers