Impact of AC Distortion & Noise on Audio Equipment

[restorer-john]

Once more: 99% of the people buying these products cannot identify any audible problems like this.

Absolutely. That's what I said in the post above.

All I am saying is don't throw the baby out with the bath-water. People these days focus on absolutes. They are either black or white. Such is not the case with filtering, particularly targeted and specific filtering. I know you know that.

 

[pma]

People these days focus on absolutes.

... simple absolutes, that is too bad. The society is polarized and the same applies to audio community. Extreme positions are not good and not helpful. In fact both have attributes of blind faith.

 

[Francis Vaughan]

Hang around any high-end forum and you clearly see why people buy them. They get them, plug them in, and all of a sudden veil is removed. Backgrounds are darker, microdynamics improved, etc., etc.

Sure, there are no end of idiots. They buy special cables and cable lifters for the same reasons. But I'm not sure the prime goal of ASR is to save these people from themselves. They refuse to be convinced about a lot of other woo, so why would measurements here help? Whilst they are seriously annoying, I don't think they deserve the attention being given to them.

OTOH, readers here care about technical and scientific facts. There really are people that would like to know about real issues with AC sensitivity, and have some quantified understanding. It furthers the state of the art. Showing that some indefinable veil is lifted or not isn't what nost of us here care about. We do care about real world issues, and quantifying them. Nobody here is ever going to consider buying one of those silly tube based bits of rubbish, so testing them doesn't really interest us. However knowing if a legitimate device is resistant to audible interference from power line modulation caused by signalling or perhaps noisy equipment in the vicinity would be of great value. There is a lot of evidence this matters. Not because it lifts veils or not, but because it is annoying.

 

[Mrgoogle]

Amir, DAC went crazy by noisy main supply ?! can you verify it why , maybe you get ground loop problem through your PC and AP and BK and DAC .
your "state of art DAC" sadly has not galvanic isolation between USB port and analog port ,
my NAIM DAC has galvanic isolation between USB port and analog output .
see here >>>> https://www.naimaudio.com/sites/default/files/products/downloads/files/naim_dac_august_2009.pdf

 

[Bars]

Hi,
I'm new to this forum and definitely no expert.
Does this mean my Thor power conditioner is pretty much useless?
Also not sure if it covered here but would adding dimming light where my Home theatre is cause distortion or hum in my setup?
Appreciate any help.
Regards,

 

[Mrgoogle]

Hi,
I'm new to this forum and definitely no expert.
Does this mean my Thor power conditioner is pretty much useless?
Also not sure if it covered here but would adding dimming light where my Home theatre is cause distortion or hum in my setup?
Appreciate any help.
Regards,

see film posted earlier

 

[JohnYang1997]

Amir, DAC went crazy by noisy main supply ?! can you verify it why , maybe you get ground loop problem through your PC and AP and BK and DAC .
your "state of art DAC" sadly has not galvanic isolation between USB port and analog port ,
my NAIM DAC has galvanic isolation between USB port and analog output .
see here >>>> https://www.naimaudio.com/sites/default/files/products/downloads/files/naim_dac_august_2009.pdf



View attachment 145435

The implementation of the isolation doesn't support usb 2.0.
And one wouldn't see any ground related issues when using balanced connection.
There are even ways to interface unbalanced output with balanced input to eliminate ground loop issue.

 

[Mrgoogle]

The implementation of the isolation doesn't support usb 2.0.
And one wouldn't see any ground related issues when using balanced connection.
There are even ways to interface unbalanced output with balanced input to eliminate ground loop issue.

I like NAIM implementation . they separate even DAC clock from USB and all digital parts , you can read in my link in details , but I think ground loop makes in some case problem especial if you connect single ended analog output to one side and USB port to other side , wonder if Amir measure the single output of DAC in his setup ? it will be interesting to measure all digital input vs DAC analog outputs

 

[uwotm8]

It's basically the same. The best mains noise filter is the rectifier with the large capacitors. The biggest noise as DC supply is what? It's the 50/60hz mains frequency residuals

That seems uncientific to me - PWM PSUs were actually made as undemanding "plug-it-anywhere" solution while linear PSUs are promoted as a "high quality" solution. That said, I'd like to see a "traditional" amplifier like, say, NAD 320 tested too, especially with that generated high distortion (which I believe is pretty rare in real life).

This is what I actually like in reviews: if something doesn't work in your usual scenario, than make it work in exotic mode. Exactly to show how exotic it is. Like Mythbusters. Yep, you can make house explode with insecticide spray - but you'll need 600 cans sprayed, not 6

 

[JohnYang1997]

I like NAIM implementation . they separate even DAC clock from USB and all digital parts , you can read in my link in details , but I think ground loop makes in some case problem especial if you connect single ended analog output to one side and USB port to other side , wonder if Amir measure the single output of DAC in his setup ? it will be interesting to measure all digital input vs DAC analog outputs

The issue of ground loop mains lies on the downstream device. If the downstream device is earthed then the issue is much more prominent. Not very prominent otherwise. It's because we don't use 5V supply from the USB for most of our devices.
The issue is more prominent on D10s as it is completely USB powered.
A straightforward solution is to add balanced input and output.
And it's not a matter you like their implementation or not. It straight up cannot work in our dacs or any modern high resolution dacs for that matter. Something that supports high speed usb 2.0 is needed for things to work fully as intended.
Amir always post one dashboard with USB in and single ended output. No issue has been found. When you chain different devices together, you start having issues.
I'm now even recommending using XLR inputs even with RCA outputs unless both devices are floating with no leakage current issue present. Bruno Putzeys also has the same recommendation.
This is how you actually solve the issue.

 

[BranoO]

And what about source (mains) impedance impact on power amplifiers? For example, PS Audio often point it out in their marketing claims. IMO, it is much easier, cheaper and more effective to do it in the power source stage of an amp itself (robust transformer, rectifier and capacitors), so stuff like PowerPlant is, in my opinion, a waste of money. But anyway, have you (amirm or anyone) tested this (probably non-existent) phenomenon on your own?

 

[respice finem]

There goes another myth...
I'm not very surprised, considering even a cheap switching PSU in a PC can provide DC stable and "clean" enough to run a modern CPU.

 

[b4nt]

A single box in a lab env may perform very well.

I had to add some stuff (mainly basic copper wires) and to mod a bit my last setup, made of different boxes (mix of SMPS and transformers, all being acceptable). Connecting my 30W soldering iron to mains was poping in audio, my fridge motor startup and more also.

 

[JohnYang1997]

And what about source (mains) impedance impact on power amplifiers? For example, PS Audio often point it out in their marketing claims. IMO, it is much easier, cheaper and more effective to do it in the power source stage of an amp itself (robust transformer, rectifier and capacitors), so stuff like PowerPlant is, in my opinion, a waste of money. But anyway, have you (amirm or anyone) tested this (probably non-existent) phenomenon on your own?

Unless the voltage saggs under the normal operation condition. There's no practical issue.

And that's why regulated power supply is better. Namely wide input range SMPS. SMPS comes with other potential issues but here is what it vastly exceeds at.

Linear regulated supplies can work but generates lots of heats. And they can only reduce voltage not boost voltage. There's only so much headroom you can design into these regulators.

 

[b4nt]

Unless the voltage saggs under the normal operation condition. There's no practical issue.

The fix being well known.

 

[PierreV]

Are you having "layering" problems with your stereo that such devices solve? Let's pray not....

I am definitely having layering issues with my setup.
The culprit has been identified: gravity.
Additional devices worsen the issue.

 

[JohnYang1997]

The fix being well known.

View attachment 145442

This is not a fix....

 

[b4nt]

This is not a fix....

Joking

 

[Addicted to music]

Go to any audiophile forums and you will bound to see talk on DC components on the mains….. Lots of solutions to including circuits to reduced DC on the mains….and nearly every discussion is brought up due to “hum” that’s audible and becomes annoying….
Audible “hum” and the assumption is it’s 50/60Hz. Another assumption is that because toroidal transformers are sensitive to DC, then the assumption here is that DC is assume to be the likely cause.
When I was working on industrial kodaks, in the PDC ( Power Distribution And Control) area use to deploy mechanical and Solid State Relays. Both types of relays use to fail, with Mechanical relays the components it powered would be dead! No power, lost of function. However SSR solid state relays were a different beast, one SSR was use to power a transformer that was a stepped down to drive other components, you knew that the SSR has failed and leaked DC into the circuit because the room that this equipment would live in would reek of something on fire! And the client would place a call to say something is burning in the equipment. If you seriously have DC on the mains than any transformer that’s connected would overheat and you would smell it.
Audible “hum” is caused by many factors such as; over mains voltage, Ive measured 263VAC where it should be 230-240VAC, ground issues through wiring and even worn supply electrolytic filter caps, a faulty transformer etc. Buying a Power filter/conditioner or regenerator isn’t going to resolve your “hum” issue, process of elimination can!

 

[Addicted to music]

Once more: 99% of the people buying these products cannot identify any audible problems like this. If someone did, sure, buy whatever and if it solves your problem, good for you.

Hang around any high-end forum and you clearly see why people buy them. They get them, plug them in, and all of a sudden veil is removed. Backgrounds are darker, microdynamics improved, etc., etc. Stuff like this review of Niagara 1200 from AudioQuest:

http://v2.stereotimes.com/post/audioquest--niagara-1200-power-conditioner/

View attachment 145433

This is what you are hearing, is it?

Or this: https://www.audiophilia.com/reviews/2020/2/14/audioquest-niagara-1200-power-conditioner

View attachment 145434

Are you having "layering" problems with your stereo that such devices solve? Let's pray not....

what’s the bet that that they have a commercial interest