Linear Power Supplies for NAS & Switches

G'day musicnuttyboy,  how do you know the SMPS units are noisy ? they are made to a much better standard than a few years ago & should comply to an emissions standard.  

I have SMPS on both my Synology NAS & Netgear switch & I cannot detect anything that is either audible or performance affecting & that includes using a lab grade linear 12vDC PSU to compare. That said I do have both downstream of my UPS & its isolation transformer & have both SMPS mains & 12vDC cables fully loaded with ferrite.

I agree its a good move to ask around for others experiences, but I would be wary of getting a linear PSU only to find it does nothing or ... worse

Fair comment Mike-B but my comments re noisy SMPS come from what I've read on this forum and others many times. 

It does appear to be a common held belief from what i can see but hey i might be wrong as It's not something i can personally substantiate.

Like RFI I can't say I've suffered from the infections.

Of course there are those who seem to seek out such troubles just to be able to recommend a never ending list of solutions.

My tip?    JLTTFM

OK,  I would let this thread run & see what comes back. 

I am not saying SMPS units are perfect, far from it, but how is noisy detected & how does it affect the audio replay & is a different PSU audibly better.  I have yet to find out but I suspect a lot of this is left over hearsay from a few years back when SMPS units were extremely basic & no doubt noisy,  but from my research I can see the latest SMPS schematics are far more complex;  however does that translate into less noisy,  I'm not sure but suspect it does.  

Practically everything in the home is SMPS these days, TV's, BRP's, PVR's, PC etc .......... & also remember a lot of hi-end audio has moved to SMPS & I don't hear bad things about them, the reverse in fact.

You're correct that some very high end gear has SMPS's, so clearly they aren't all bad. However, my understanding is it's all in the design and the cheap plug-top type are an issue.

It will be interesting to hear what views others have.

I originally commenced replacing SMPS with the Israeli devices to good effect.  Looking for a more cost-effective solution I tried  a T***dak from HK but it had an adverse effect on the mains just being plugged in, even on a different spur.

My best solution for the 'noisy bits' involves 300va or 600va toroidal screened isolating transformers, lots of ferrites, and black PSUs from the usual Israeli supplier. Also keeping maximum separation of the DSL / wifi router from my upstream switch.

Ferrites are cheap and easy to put onto mains and DC leads of SMPS, and they are an easy way to find out if your SMPSs are causing a problem.

Remember you need ferrites on most of them for it to be a valid test as if you miss one and it is a noisy one, it'll look as though the ferrites have had no effect.

You may also need to put ferrites an all your audio and network leads if you have a lot of radiated RFI in your environment.

I have a Qnap HS-251 Nas and having a "spare" linear power supply from HDPlex I used it for the NAS: I didn't notice any SQ improvement but is looks like very professional and fancy 

The powersupplies for the NAS and network equipment should have no impact, unless they are very poor quality with respect to their filtering  or faulty. If this is the case they could inject HF electrical noise onto the mains which may affect nearby audio equipment... Or if really noisy equipment further away.

By the way the device having a CE mark is not neccessarily a good indication of the device being compliant.. as it only has to be type tested and is applied by the manufacturer. The key spec is EN 50082 but even here, this is only typically type tested and degree of compliance can vary from device to device and production run to production run.

it is best to use a reputable/quality manufacturer where devices have serial numbers.

Simon

Thanks Simon and all the other contributors.

The removal of the SMPS's is purely down to getting them off my mains. Unfortunately the logistics of installing a dedicated circuit in my proprty means i'm stuck with what iv'e got so removing the pinch points appears to makes sense.

The other option i'm considering is a balance isolation transformer but i've read very mixed views on that subject. 

@Musicnuttyboy, do you hear notable difference in audio performance when you remove the suspect devices with the SMPS? Is one device notably worse than an other? If so that might be the guilty culprit..

The SMPS's are on my NAS and associated switch so used for audio playback. I'll copy some albums onto a stick and play from that which will allow me to listen with and without the SMPS's connected.

Unfortunately that doesn't cleanly test for the influence of the SMPSs on the mains.

If there's no improvement then, the SMPSs are OK and not degrading the sound.

However if the USB stick playback is better, then there may be a problem with RFI pick-up in the network cables.

If the USB stick playback is better, then switch the router, switch and NAS back on, but continue to play back from the USB Stick.  If this degrades the sound, then one or more of the SMPSs is likely to be the culprit.

You can also test the effect of the network connection by comparing USB playback with and without the network cable plugged into the streamer.

After a long time playing with ferrites and other RFI suppression, my system now sounds as good from the network as it does with just a USB stick, so it can be done even in areas with quite a lot of RFI and mains problems.

For the last fortnight I've been using an HDPlex LPS to power the fanless PC I use as my digital source.  Made a significant improvement to sound for not much money and seems well built. But I'm   afraid I have no idea if it would bring any benefit when used to power a NAS.