How is this possible? Shunyata power line filtering (with video)

[audio_tony]

* USB power is notoriously noisy. It has no effect on the digital audio data but sometimes it gets into the analog circuitry. Usually the DAC (or audio interface, etc.) filters it out but sometimes the filtering is imperfect. If you hear the noise it's usually a high-pitch noise from the computer's switching power supply or from the digital switching inside the computer. The computer's power supply is pretty-well isolated from the AC power line.

People keep saying this, but for the most part, USB power isn't noisy at all. No, it really isn't.

The biggest issue with USB fed DACs is ground loops.

I did some measurements of USB fed DACs using a Pi, Intel NUC and a laptop, none of which had this famous USB noise.

With some laptops, the power brick itself can cause noise on the USB, but this is noise injected from the power supply and not USB noise as such.

I have 3x PCs that I use for audio testing (i3, i5 and i7) and none of these have noise on the USB bus. Modern motherboards simply don't suffer from PSU noise in my experience.

USB noise measurements

USB noise measurements, Raspberry Pi, Intel NUC, PC, USB DAC

gtkc.net

 

[antcollinet]

The biggest issue with USB fed DACs is ground loops.

This.

 

[617]

Expensive amplifiers are basically just huge fancy power supply filters which are then modulated by a transistor. The power supply filter isn't an additional element of the design, it's like 70% of what you're buying.

Clean power is essential to the function of electronics. We've figured out to make very efficient, very clean power at low cost. If we didn't, put computers wouldn't work and our tvs would flicker.

OK, let me sum up what has been mentioned in this thread and what I have learnt:

1. Noise in mains power lines is common. It can be injected via radio transmissions, other household appliances, and Ethernet over Power.
2. This has no effect on performance of audio electronics if there is a decently designed power supply. This has been tested by Amir in several reviews of power conditioning products.
3. The only way noise can affect audio electronic performance is via the ground.
4. Common loop ground filtering via galvanic isolation can be applied if necessary.

 

[egellings]

Are you plagued by weird noises in your system that can not be linked to ground loops ?
If not... you don't need any of this.

Every wire is also an antenna so it will pick up all nearby radio stations (micro-volt at best).

Filtering of mains is not voodoo or a black art. Some well placed inductors and capacitors can already bring improvements.
Measured improvements does NOT mean this will result in audible improvements.
These are separate things and all electronic equipment should be immune to crap on mains... simply because mains is NEVER 'clean'

I use just bog-standard UL/CE-approved power cords that come with the equipment and I've not had any problems with noise or sound quality issues attributable to them at all. They just get the job done adequately.

 

[solderdude]

I have never been plagued by any of this either.
That's why I asked if he experienced any of the described problems.

 

[Balle Clorin]

I have tested and measured these things and my simple EMI meter is much more sensitive than the Isotek one. And a simple Bajog filter for 50 bucks does a better job than an Isotek “cleaner” for 1500 usd..
Power filtering does reduce mains noise , but mains noise is not a problem at the output on any amplifier or Hifi things … So it does nothing to the sound quality.

A light dimmer or washing machine makes poweline noise. But do you notice a difference with the dimmer or not ? I do not.
My home got a new higher capacity power inlet, and the noise according to the EMI meter dropped by 75% , but it was no change to the Hifi sound..

 

[Keith_W]

Expensive amplifiers are basically just huge fancy power supply filters which are then modulated by a transistor. The power supply filter isn't an additional element of the design, it's like 70% of what you're buying.

Clean power is essential to the function of electronics. We've figured out to make very efficient, very clean power at low cost. If we didn't, put computers wouldn't work and our tvs would flicker.

Well, yes. It would be a great answer if the question was "does this power gizmo improve the sound of my amplifier". But I did not ask that question! I was baffled at how this thing could possibly work on the other socket which it was not plugged into.

 

[fpitas]

Well, yes. It would be a great answer if the question was "does this power gizmo improve the sound of my amplifier". But I did not ask that question! I was baffled at how this thing could possibly work on the other socket which it was not plugged into.

At a guess? It has a biggish capacitor or capacitors that shunt some of the high frequency noises.

 

[Soniclife]

I was treated to a demo of ferrites yesterday in my audio system. It happened because I learned that my mains electricity is *very* dirty and I am told this noise it affects audio quality. I’ve also been told that components themselves create considerable noise. I have been “infected” with the audiophile bug so I feel compelled to want to improve the SQ. My visitor brought 4 power cords fitted with as many ferrites as would fit on the power cord. The first cord was just plugged into an outlet and allowed to dangle. We listened and I swear I could hear a slight improvement. We then replaced the ordinary power cord on my tube amp with a ferrite loaded power cord and I almost immediately I detected an improvement in clarify. Individual instruments stood out. We went back and forth several time in classic a/b fashion and always detected an improvement with ferrites in place. We did the same with my DAC and my Oppo 205 with similar results. The ferrites were encircling a $300 power cord and covered the entire length. I would appreciate any explanation of how this can possibly work. What kind of noise do ferrites target? Is it the same noise as Shunyata power cords?

You have a great opportunity to learn something really important, that your brain makes stuff up and lies to you, and you shouldn't trust it. As already pointed out you should repeat this using a blind test, and it needs to be double blind, once this is done, and it's ears only things will look different. Go back and forth between sighted and unsighted, until you are satisfied you have the truth of the situation.