I plugged a powerline wifi adapter in the mains socket close to my tube preamplifier. Now there is ticking sound. The peamplifier is an IEC Class I device, the chassis is connected to the mains protective earth. The signal ground is connected to the chassis with hum blocking antiparallel diodes (35 Ampere Graetz). The mains input of the preamplifier has "some" AC noise filter.
If I place the powerline adapter in a different socket several meters apart (perhaps on a different phase? I have a 3-phase installation in the house) the noise disappears.
Is there any way to block this noise? It seems data is being propagated on the mains wiring and it is disturbing the audio cicuitry. I am looking for a more effective filtering.
If I place the powerline adapter in a different socket several meters apart (perhaps on a different phase? I have a 3-phase installation in the house) the noise disappears.
Is there any way to block this noise? It seems data is being propagated on the mains wiring and it is disturbing the audio cicuitry. I am looking for a more effective filtering.
Powerline ethernet adapters are placed on outlets which share the same phase from the breaker. As you discovered different phase removes noise.
That means you need to have the powerline adapter on that other phase from audio branch but then also find a suitable matched outlet in the destination room which the other adapter is located to provide the network connection you require.
I cannot speak to how the data signal is modulated onto the AC line and what type of filter could completely eliminate it.
That means you need to have the powerline adapter on that other phase from audio branch but then also find a suitable matched outlet in the destination room which the other adapter is located to provide the network connection you require.
I cannot speak to how the data signal is modulated onto the AC line and what type of filter could completely eliminate it.
Powerline adapters are RF transmitters on the power line 🙂 This means you pollute the mains voltage yourself in various ways. If you wish to filter and have clean mains voltage again the powerline system will not work properly. Chicken-egg issue.
This can be solved by using wired ethernet. When using ethernet wall sockets it also looks OK. Many seem to think this is difficult but retrofitting often is doable. You will have reliable fast connections and cleaner mains power.
Secondly the power supply of that amplifier is not well designed if it lets the pollution through.
This can be solved by using wired ethernet. When using ethernet wall sockets it also looks OK. Many seem to think this is difficult but retrofitting often is doable. You will have reliable fast connections and cleaner mains power.
Secondly the power supply of that amplifier is not well designed if it lets the pollution through.
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Secondly the power supply of that amplifier is not well designed if it lets the pollution through.
You are right, but could you give me some hints how could I make my preamplifier more tolerant to mains disturbances?
You are right, but could you give me some hints how could I make my preamplifier more tolerant to mains disturbances?
I have Powerline adapters in my home. They interfere with my older vintage valve guitar amps, but not more modern stuff (valve or solid state).
It seems to be conducted interference: using a well filtered power strip for them suppresses the interference enough. I didnt try the supposedly filtered pass-through socket on the powerline adapter, but I suppose that would mitigate it too.
I guess then that your first step is to try a filtered power strip. If that sorts it, then fitting a good emi power filter to your susceptible gear should sort it. Or just use the filtered power strip. 😁
If it is being picked up as radiated noise, then there's a whole other voyage of discovery!
Good luck.
Cheers, and regards,
Ant
It seems to be conducted interference: using a well filtered power strip for them suppresses the interference enough. I didnt try the supposedly filtered pass-through socket on the powerline adapter, but I suppose that would mitigate it too.
I guess then that your first step is to try a filtered power strip. If that sorts it, then fitting a good emi power filter to your susceptible gear should sort it. Or just use the filtered power strip. 😁
If it is being picked up as radiated noise, then there's a whole other voyage of discovery!
Good luck.
Cheers, and regards,
Ant
Still solving problems at the root by not letting them exist is most effective. As explained you have introduced (apparently strong) RF both via mains and via air. The closer to your equipment the more "benefits" you enjoy. Disable/remove both for testing and check the difference. Is the convenience worth the deterioration?
Filtering what you injected seems counterproductive in a few ways as the powerline system wants good signals to function right. It is like testing the fire extinguishers function by starting a house fire.
The laymen solution would be to use L1 for power line adapters to function right and connect audio to L2 or L3. That will not prevent the radiated RF. Rearranging wall socket wiring is comparable with the time and effort to install a wired ethernet network so no gains there. It is in many countries also forbidden to work on mains installations when not certified.
In short: you have discovered RF to be an enemy of good audio.
Filtering what you injected seems counterproductive in a few ways as the powerline system wants good signals to function right. It is like testing the fire extinguishers function by starting a house fire.
The laymen solution would be to use L1 for power line adapters to function right and connect audio to L2 or L3. That will not prevent the radiated RF. Rearranging wall socket wiring is comparable with the time and effort to install a wired ethernet network so no gains there. It is in many countries also forbidden to work on mains installations when not certified.
In short: you have discovered RF to be an enemy of good audio.
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And... better?
Many clever guys mention that RF can't be heard. That is too simple as intermodulation products are heard by ear. If one happens to live near a cell phone transmitter one will understand quickly. RF introduced by whatever medium is hard to get rid off. I have experienced devices to lock up from strong RF caused by another favorite the famous SMPS.
So it still is advisable not only to not use RF introducing devices but also have the extra filtering for RF introduced by environment/neighbours. IEC chassis mount inlets with built in filters may do a good job but not all are good. If you wish to upgrade those for known good ones by Schaffner, Schurter, Corcom etc. please choose one with a suitable current rating and ALWAYS check the built in fuses rating. They can be quite effective provided the PE connections in the home installation are good. Filtering on a per device basis is best. Power distributors with built in filter are OK but less effective.
Input filtering of preamp/amplifiers is also advisable. Clip on ferrite beads are nice for testing if you lack the equipment to measure.
Many clever guys mention that RF can't be heard. That is too simple as intermodulation products are heard by ear. If one happens to live near a cell phone transmitter one will understand quickly. RF introduced by whatever medium is hard to get rid off. I have experienced devices to lock up from strong RF caused by another favorite the famous SMPS.
So it still is advisable not only to not use RF introducing devices but also have the extra filtering for RF introduced by environment/neighbours. IEC chassis mount inlets with built in filters may do a good job but not all are good. If you wish to upgrade those for known good ones by Schaffner, Schurter, Corcom etc. please choose one with a suitable current rating and ALWAYS check the built in fuses rating. They can be quite effective provided the PE connections in the home installation are good. Filtering on a per device basis is best. Power distributors with built in filter are OK but less effective.
Input filtering of preamp/amplifiers is also advisable. Clip on ferrite beads are nice for testing if you lack the equipment to measure.
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Hm, good advices, especially the ferrite beads. I have IEC socket with built-in filter in my preamplifier. I have to check whether all metal parts of the chassis sides, bottom and top are connected to the safety earth pin of the socket.
Now my system is dead silent.
Now my system is dead silent.
Check the brand and type of the IEC with builtin filter. Not all are good. That one is not good as it passed garbage.
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Please see the article on ferrite beads attached to: https://www.diyaudio.com/community/threads/general-purpose-dac-clock-board.413001/post-7765137
Also of possible interest from Bruno Putzeys: https://ptt.purifi-audio.com/blog/tech-notes-1/this-thing-we-have-about-hysteresis-distortion-3
I gave up on them. I couldn't be bothered to jump through the hoops to negate the noise they introduced. I put the effort into getting a good router and WiFi signal which had more general benefits.
Theres no doubt that powerline adapters are horrible from.tthe interference / EMI point of view. Radio hams hate them for the hash / mess that the house wiring spews out. JP is entirely correct: eliminating them and replacing with hard-wired ethernet, or a good wifi, is a better option. Prevention being better than a cure and all that.
As long as it works for your use case. At the moment, it doesnt for us in our house.
But for me, only my vintage stuff seems to suffer from the interference, so I can live with it with a filtered power strip. YMMV of course....
Cheers, and regards,
Ant
As long as it works for your use case. At the moment, it doesnt for us in our house.
But for me, only my vintage stuff seems to suffer from the interference, so I can live with it with a filtered power strip. YMMV of course....
Cheers, and regards,
Ant
There are no real substitutes for wires and also not for clean power. Both are essential if the goal is highest quality. All other concessions are detrimental for quality.
If you pass the red line and let convenience and features have more priority over quality then there is no experienced problem. Then all is OK. Fans in audio stuff, SMPS, bluetooth streaming, power line adapters, lossy compression.... One can then worry about details but in fact tubes are then only nice to look at and class A is then a hollow phrase. One does have the time to worry about caps dielectric then 😀
If you pass the red line and let convenience and features have more priority over quality then there is no experienced problem. Then all is OK. Fans in audio stuff, SMPS, bluetooth streaming, power line adapters, lossy compression.... One can then worry about details but in fact tubes are then only nice to look at and class A is then a hollow phrase. One does have the time to worry about caps dielectric then 😀
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