Mains noise suppression - seeking for advice

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ginetto61

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Mains noise suppression - seeking for advice
« on: 6 Feb 2019, 04:19 pm »
Hi !   after reading some interesting words about how dirty the mains voltage can be i decided to take some action and i bought on ebay this device

https://www.ebay.com/itm/OLED-Digital-AC-Noise-Meter-EMI-Tester-Wideband-AC-Power-Ripple-Analyzer/292907454245?hash=item4432a50f25:g:yBAAAOSw3BJcMwGA:rk:4:pf:0

i really do not know if it is dependable but actually i am reading indeed some noise changing from 150 mV up to 800 mV i guess depending on the switch on of some appliances in the home grid ?
Anyway,  i have also bought a Adam Hall not filtered power strip
https://www.thomann.de/it/adam_hall_874716_power_strip_1_u_19.htm
my idea would be to place something  just before (or even inside with a little DIY work) this strip to improve things.  A filter ? an isolation transformer ?
I have looked around but i am very confused and a little scared by the price of some units. 
here in Europe we have 220VAC nominal. 
Any kind advice would be very appreciated
Thanks a lot.  Regards, gino

P.S. i am usually listen music files from a personal computer through headphones driven by an old benchmark dac1 1st edition.

rollo

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Re: Mains noise suppression - seeking for advice
« Reply #1 on: 6 Feb 2019, 05:21 pm »
There is a DIY filter called Felix here in the Lab I believe. You could measure then insert Felix and measure again. Or you could borrow a well known PC from a dealer or friend. Same procedure. :popcorn:


charles

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Re: Mains noise suppression - seeking for advice
« Reply #2 on: 6 Feb 2019, 08:42 pm »
But  150 mV up to 800 mV is quite! Any component hi-fi component should deal with way more than that.
But you might be able to track down even that small amount of noise.
Does it change with time of day, day of the week, season or which hi-fi components are on?
It's best to attack noise at it's source.

Elizabeth

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Re: Mains noise suppression - seeking for advice
« Reply #3 on: 6 Feb 2019, 09:30 pm »
Here is ny experience with a noise sniffer. The exception is I was already doing plenty to get rid of the noise.
link to my thread https://www.audiocircle.com/index.php?topic=162162.msg1727059#new

Folsom

Re: Mains noise suppression - seeking for advice
« Reply #4 on: 6 Feb 2019, 10:37 pm »
But  150 mV up to 800 mV is quite! Any component hi-fi component should deal with way more than that.
But you might be able to track down even that small amount of noise.
Does it change with time of day, day of the week, season or which hi-fi components are on?
It's best to attack noise at it's source.

Depends on the frequency, too.

ginetto61

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Re: Mains noise suppression - seeking for advice
« Reply #5 on: 7 Feb 2019, 07:58 am »
But  150 mV up to 800 mV is quite!   Any component hi-fi component should deal with way more than that.
But you might be able to track down even that small amount of noise.
Does it change with time of day, day of the week, season or which hi-fi components are on?
It's best to attack noise at it's source.   

Hi ! yes that is what i am reading.  Yes it is changing i think due to some appliance on the circuit waking up i think.  It was just a quick first test.
In the weekend i will get a power strip and place all my power cord on it to test one by one and see if they have any effect on the noise. 
I will try to look inside the unit and see how the sockets are connected.  I hope they are not in series.  I think that some kind of re-wiring could be possible.  Like star earthing or similar.  It will be a testing bench.  I like it because it has socket on the front and on the back. 

There is a DIY filter called Felix here in the Lab I believe.
You could measure then insert Felix and measure again.
Or you could borrow a well known PC from a dealer or friend. Same procedure. :popcorn:  charles 

Found ! thank you very much !   https://www.audiocircle.com/index.php?topic=25757.0

Hi ! very interesting.  Is the Lab a dedicated circle on this site ?  this is what i would like to try first.  A simple passive DIY filtering solution.  It could be quite beneficial.  Anyway i would like to make clear that i am quite confused about power supplies in general.  Just to give you an example and speaking of digital sources i read often that very clean voltage for clock circuits is mandatory to provide stability and that smps are not the best solution.  And then i see master clock generators using smps ... so i get confused a lot.  Now i have bought this little and unassuming device and indeed it measures some kind of noise. 
So the testing can start.   I will try all the power cords i have already at hand and see if they lower this noise.  Maybe i will discover a hidden gem ...

Depends on the frequency, too.   

Hi ! i understand that without a proper wideband scope the measurements are very limited.  And that is indeed my long term idea.  To get a proper scope.  Unfortunately i have little free time now and also often moving from place to place.  But when i will be settled down i want to make this my full time hobby. 
With a scope i could see directly the effect of a filter i guess.

Here is ny experience with a noise sniffer. The exception is I was already doing plenty to get rid of the noise.
link to my thread https://www.audiocircle.com/index.php?topic=162162.msg1727059#new

Hi ! thank you very much indeed.  I am studying the thread.  I am not very educated in electronics.  I hope to understand the most. 

Thanks to all of you sincerely.
Kind regards, gino
« Last Edit: 7 Feb 2019, 12:22 pm by ginetto61 »

Elizabeth

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Re: Mains noise suppression - seeking for advice
« Reply #6 on: 7 Feb 2019, 01:12 pm »
My experience with the noise sniffing device made it clear to me, that a few devices, particularly digital devices add a gret deal of garbage to the AC line. and some device actually reduce the grunge on the AC line.
The worst offenders for me are my five disc CD changers. But the expensive Marantz SACD player adds no garbage to the line at all.
For non stereo equipment offenders, the worst is my laptop charger, seconded by the recliner motor power device. And finally a dimmer switch on a separate circuit. (I moved the two power supples off the Audio AC, and the CD changers are separated by using them from a dedicated power conditioner.

rollo

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Re: Mains noise suppression - seeking for advice
« Reply #7 on: 7 Feb 2019, 05:53 pm »
  Yes Digital throws some nasties on the line. Try un-grounding your digital if using on same AC line as analog gear. When I stated PC previously I meant power conditioner not power cord.
  Do you have a dedicated AC line ?



charles

ginetto61

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Re: Mains noise suppression - seeking for advice
« Reply #8 on: 11 Feb 2019, 09:07 am »
My experience with the noise sniffing device made it clear to me, that a few devices, particularly digital devices add a gret deal of garbage to the AC line.
and some device actually reduce the grunge on the AC line.  The worst offenders for me are my five disc CD changers. But the expensive Marantz SACD player adds no garbage to the line at all.
For non stereo equipment offenders, the worst is my laptop charger, seconded by the recliner motor power device. And finally a dimmer switch on a separate circuit.
(I moved the two power supples off the Audio AC, and the CD changers are separated by using them from a dedicated power conditioner.   

Hi ! very interesting again thank you.  Actually peeping inside some filtered power strips of good reputation (and high price) i see that each outlet is individually filtered.  I guess these filters work both ways ... suppressing incoming and outgoing noise.  They seem to work very nicely.  This for low current outlets. That is what interests me more.