Do you need AC Noise Filtering For Your Audio Devices?

[Plcamp]

The only reason FM transmissions are not called common mode noise is because they are intentional.

so yes, it is possible for unintentional rf noise to disrupt audio equipment. Indirect ESD is also common mode noise.

that doesn’t give reason to suspect a majority or anything near a majority of products are likely to experience problems. I think it highly unlikely in the vast majority of environments

there will always be exceptions

 

[Pdxwayne]

The only reason FM transmissions are not called common mode noise is because they are intentional.

so yes, it is possible for unintentional rf noise to disrupt audio equipment. Indirect ESD is also common mode noise.

that doesn’t give reason to suspect a majority or anything near a majority of products are likely to experience problems. I think it highly unlikely in the vast majority of environments

there will always be exceptions

Thanks! If one has a setup that contains a certain device with such exceptions, would using external AC filter even help?

 

[Lambda]

Common mode noise relevant at all for audio quality?

Yes it can be.*
As shown you can do lot of things to make it "not as bad"
like isolation transformer, common mode filters,track down all noise sources etc.

Or just use Balanced connections

*maybe its bellow hearing threshold

 

[Pdxwayne]

Yes it can be.*
As shown you can do lot of things to make it "not as bad"
like isolation transformer, common mode filters,track down all noise sources etc.

Or just use Balanced connections

*maybe its bellow hearing threshold

Thanks!

What if the issue is on the power amp, which is the last one on the chain before speakers? Then using balanced connections wouldn't help in that case, correct?

Also, let's say the amp is capable of 20hz to 100khz response. If there are lots of noise in area that is not audible, lets say 66khz, would those extra noise cause the amp to not function as well in the audible range, like below 20khz? I wonder if there is already such study available.

 

[Lambda]

What if the issue is on the power amp, which is the last one on the chain before speakers? Then using balanced connections wouldn't help in that case, correct?

Don’t fully get this. if the amp itself is a noise source it's not a verry good amp...

it is not like using a balanced connections is magically solving all problems but it is less like for noise to enter the system over the balanced connection.

lets say 66khz, would those extra noise cause the amp to not function as well in the audible range, like below 20khz? I wonder if there is already such study available.

Sure it can be causing inter modulation. but at very least it would waste power and put load on your tweeters.

But if you hear no problem there is probably no problem.

 

[Pdxwayne]

Don’t fully get this. if the amp itself is a noise source it's not a verry good amp...

it is not like using a balanced connections is magically solving all problems but it is less like for noise to enter the system over the balanced connection.


Sure it can be causing inter modulation. but at very least it would waste power and put load on your tweeters.

But if you hear no problem there is probably no problem.

I know this one is a "marketing" video. But he claims the benefits are in the audible range.

If the video really is showing a difference, it would mean even modern digital audio devices can still benefit with external filter?

If I am going to verify his claims, do you think checking like this would work?

Play REW sweep from laptop -> DAC -> ADC -> laptop -> capture via REW.

First plug everything to normal power strip and run sweep.

Next plugin everything to Furman power conditioners and run same sweep again.

Compare the captured graphs in REW?

Thanks!

 

[Plcamp]

“What if the issue is on the power amp, which is the last one on the chain before speakers? Then using balanced connections wouldn't help in that case, correct?”

Guess what the very first thing a good (unbalanced) power amp does? It applies the input signal to a differential amp, and one dominant reason it does that is to forcefully reject common mode noise.

 

[respice finem]

Furman isn't snake oil, many German studios use their stuff.

 

[Lambda]

it would mean even modern digital audio devices can still benefit with external filter

if it is not already properly filtered and uses unbalanced connection.

Furman isn't snake oil, many German studios use their stuff.

but snake oil marketing...

looks like they selling an isolation transformer. isolation transformers can real make a difference.

 

[Plcamp]

Furman isn't snake oil, many German studios use their stuff.

Just because many people use x does not mean x does anything useful.

Just because some population of folks believe y, however popular such people are, does nothing to validate y.

I do not dispute that series inductors, single ended or common mode, in conjunction with well engineered shunt elements and faraday cages can rf isolate an ac power supply from its load.

But the claims of benefit, without mentioning that those benefits are likely to make no difference in many circumstances just isn’t worth considering, unless you have a specific problem that you have reason to believe this specific filter can solve.

Agreed?

 

[respice finem]

...but snake oil marketing...

All marketing is (bordering to) snake oil somehow... "Marketing is the Art of selling a cuckoo clock bundled with 50kg of bird seed"

 

[respice finem]

Just because many people use x does not mean x does anything useful.

Just because some population of folks believe y, however popular such people are, does nothing to validate y.

I do not dispute that series inductors, single ended or common mode, in conjunction with well engineered shunt elements and faraday cages can rf isolate an ac power supply from its load.

But the claims of benefit, without mentioning that those benefits are likely to make no difference in many circumstances just isn’t worth considering, unless you have a specific problem that you have reason to believe this specific filter can solve.

Agreed?

Basically yes, but what would you say from a marketing position? I don't think it is realistic, if we start to expect that everyone will just present the raw data and shut up. Selling stuff doesn't work that way

 

[Plcamp]

Basically yes, but what would you say from a marketing position? I don't think it is realistic, if we start to expect that everyone will just present the raw data and shut up. Selling stuff doesn't work that way

And that’s precisely why we need places like this.

 

[Lambda]

A studio is a very dynamic environment with lots and lots of gear that gets reconfigured all the time.
Musicians bring in there own old crappy and gear...
And Studio time is super expensive.

So it makes sense to uses isolation transformers.

 

[Pdxwayne]

“What if the issue is on the power amp, which is the last one on the chain before speakers? Then using balanced connections wouldn't help in that case, correct?”

Guess what the very first thing a good (unbalanced) power amp does? It applies the input signal to a differential amp, and one dominant reason it does that is to forcefully reject common mode noise.

Would that differential amp help if it is the power supply of the amp that have noise issues?

Thanks!

 

[Plcamp]

Would that differential amp help if it is the power supply of the amp that have noise issues?

Thanks!

Think about that question.

Were it internally generated noise of the same amp, that amp’s specs would never sell. It would never make production. It wouldn’t exist.

 

[Pdxwayne]

Think about that question.

Were it internally generated noise of the same amp, that amp’s specs would never sell. It would never make production. It wouldn’t exist.

No, not internal generated noise.

It was more about if the power supply could be susceptible to outside interferences,
like the cases in post #60 video:

https://www.audiosciencereview.com/...ring-for-your-audio-devices.21057/post-700461

 

[respice finem]

Just a "loose thougt" - do all amps meet their stated specs? After all tests seen here, we all know the answer.

 

[stunta]

Maybe I test a few power strips to see how they do.

That would be great.

If a decently power strip does the job without limiting current, that might dissuade folks from spending thousands of dollars on fancy audiophile conditioners. I bought a shunyata unit once and it made the sound much worse - the woofers started bottoming out.

 

[tifune]

Q about this - Amir's review of the Meizu non- Pro was contested a bit and one of the suggestions was his PC USB was polluting the outcome. Assuming that's true, and I'm not sure it is although a few other reviewers got far better results with a phone, would an AC filter help in that scenario? Or is that issue internal to the PC/Mac? Or neither, both...? It doesn't have to be the Meizu, that was just the first one I thought of but I wonder if it would help with any dongle connected to a desktop.