What can I do to minimize electromagnetic radiation from power amplifiers?

[RayDunzl]

If anyone cares to measure some radiated electrically produced force, stick your probe someplace in the vicinity of the stators of a big electrostat playing loudly.

 

[Deleted member 9685]

- Measurement

You can measure AC magnetic field and AC electric field below 100khz with consumer-level EMF meters such as ME3830B which I have.
With a more expensive EMF meter such as ME3851A, you can measure magnetic field and electric field below 400khz.
ME3851A is more sensitive and thus more appropriate.

Both electromagnetic radiation and electric field can be masured by V/m. I suspect electric field and electromagnetic raidation are interchangeable because they can be expressed in the same unit.

For electromagnetic radiation or electric field between 100khz and 30mhz, you can use Tecsun PL-600.

Above 30mhz, you can use TriField TF2.

I think it is measurable. Rather than intellectualizing over whether class AB amps produce a lot of magnetic field, I'd rather buy an affordable class AB amp and measure magnetic field around it with ME3830B. If I had ME3851A, I may also measure electric field portion of electromagnetic radiation around it. ME3830B is not sensitive enough for measuring electric field portion of electromagnetic radiation.

Usually, intense magnetic fields are created by pieces of metal moving against each other(e.g. motors) or hot lines that are not matched by neutral lines. I don't yet know other sources of magnetic field. In my imagination, as long as load current(hot line) and return current(neutral line) are evenly matched in a power amplifier, there should be no intense magnetic field around it.

- Sources of EMF

• Power supply noise.
  • Linear power supply generally cleaner than switch mode power supply although actual results depend on implementations.
• Electromagnetic radiation at class D PWM frequencies
  • A class AB amp doesn't have this problem.
• Electromagnetic radiation at audio frequencies??
  • All power amplifiers have to operate at audio frequencies.
  • Emosg Spion or ME3851A may be able to measure it.
  • I want to compare class AB and class D at audio frequencies.
• Electromagnetic radiation at other frequencies
  • This is probably due to other kinds of electronic circuitry in power amplifiers.
  • I think most of it can be measured with Tecsun PL-600.

- Possible Practical Solutions?

• Compare class D with class AB amp.
• Use shielded audio cables.
• Linear power supply or a better switch mode power supply. You can also attach noise suppression measures(e.g. common mode choke) to a switch mode power supply.
• Whole-house dirty electricity filter if you want to go extra mile. Whole-house dirty electricity filter is good for lengthening equipment lifespan and is also known to have health benefits over long term.
• Fabricating a custom faraday cage for your amp. Making one would be tough for me because I don't know much about making physical stuff.

 

[JustJones]

There is an electromagnetic field around every wire in your house and any appliance that uses electricity. I'm confused what you're trying to accomplish?

 

[Deleted member 9685]

There is an electromagnetic field around every wire in your house and any appliance that uses electricity. I'm confused what you're trying to accomplish?

Creating low-EMF environment. Power amplifier is an aspect of it. If you research, you can surprisingly do a lot to almost eradicate electric field and magnetic field. I have done so over the last few months. If you have money, you can reduce EMF faster.

For example, just by grounding your power amplifier to electrical ground, you instantly eradicate almost all electric field around your power amplifier. When you touch an ungrounded metal power amplifier, you can feel tingling sensations on your finger. That means electric field is between 500~2000V/m.

 

[JustJones]

If you don't have an EMF then you don't have electricity. I think the Amish have figured out how to reduce the EMF in their environment.

 

[Deleted member 9685]

If you don't have an EMF then you don't have electricity. I think the Amish have figured out how to reduce the EMF in their environment.

The goal is to minimize EMF without giving up electronic appliances. It's possible.It just takes research over time. It's not practical to not use any electronic appliance at all.

I understand that EMF research is not interesting for many people. If you are not interested, you can choose to browse other threads.

 

[JustJones]

If you reduce EMF by 50% what have you gained? What's the purpose? Energy savings?

 

[Deleted member 9685]

If you reduce EMF by 50% what have you gained? What's the purpose? Energy savings?

My goal is to reduce EMF by at least 99%. It's attainable.
Although it's about health for me, this thread should be about reducing EMF from power amplifiers.
Let's keep it strictly about technicalities of reducing EMF from power amplifiers in this thread.

If you are not already interested in reducing EMF, I request that you go to other threads. I'm not here to convince you to reduce EMF if you are not already interested. I'm not an asshole that keeps bothering people with unsolicited advices. I'm just here to do my own technical research with people who are interested in doing the research with me.

 

[JustJones]

Put a steel mesh screen around it.

 

[Deleted member 9685]

Put a steel mesh screen around it.

I think that's a good material for faraday cage. I think shielded audio cable and faraday cage can go a long way.

 

[solderdude]

For example, just by grounding your power amplifier to electrical ground, you instantly eradicate almost all electric field around your power amplifier. When you touch an ungrounded metal power amplifier, you can feel tingling sensations on your finger. That means electric field is between 500~2000V/m.

You feel the leakage current of the power supply. When a device has a 3-prong mains plug it should be connected to a grounded (3 prong) mains outlet. Period.

 

[zelig]

 

[Chromatischism]

Let me guess: you think cell towers are harmful to your health, too? And Wi-Fi? AM/FM radio? TV broadcasts? Satellite radio and internet signals? GPS?

You might want to avoid sunlight while you're at it.

 

[mansr]

Should we tell him about neutrinos?

 

[StefaanE]

Go to Ikea and buy this to put your amplifier in:

 

[Harmonie]

Why just the amplifier ?

Build your house in !!!

 

[Harmonie]

More seriously and not related:

Do you folks in US have smart (electrical) grid ?
In France they impose you little by little communicating electrical counters.
These use Ghz waves to monitor your consumption in your home so many debates about freedom, health harmful aso.
I simply wonder if there is not a lot of dirt added in the power line delivering no more simply just 50Hz anymore.

Would that influence our Hifi ?

 

[mnemonix]

More seriously and not related:

Do you folks in US have smart (electrical) grid ?
In France they impose you little by little communicating electrical counters.
These use Ghz waves to monitor your consumption in your home so many debates about freedom, health harmful aso.
I simply wonder if there is not a lot of dirt added in the power line delivering no more simply just 50Hz anymore.

Would that influence our Hifi ?

Wifi also works at GHz frequencies similar to the radio bands used for smart meters. Do you believe this influences your HiFi?

A smart meter introduces nothing, dirt or otherwise into the power line.

 

[Harmonie]

I see,

So we have clean power ? Even better than DC from batteries ?

 

[StefaanE]

I see,

So we have clean power ? Even better than DC from batteries ?

Not necessarily, but the crud on the lines is not coming from smart meters.