Power grid interference: What does it look like measured with different tools?

[Chrispy]

What you have to worry about is impedance. AC from wall sockets is normally really good/low impedance, that is why electric motors that are used in a lot of equipment can be run from it (people in the construction industry generally don't need expensive power conditioners for their power tools for example). It is however possible that you have bad impedance where you live, but that should not be considered as a normal/acceptable situation.

So AC regenerators, especially an uninterruptible power supply often do not give an audible improvement. If the music sounds lighter and is missing bass with a power conditioner, it is most likely because it has worse/higher impedance.

All you had to do was record some music from the line level output of hi-fi equipment with and without a power conditioner, but the reason we don't see that is because decent hi-fi equipment smooths out the DC and removes the AC interference (called ripple current) by using capacitors or some other electronic component.

You're probably better off upgrading your capacitors than buying some questionable AC regenerator. Just know that they can store enough energy to kill you, know what you are doing before capacitors are replaced.

But please use a surge protector as voltage spikes can actually be an important problem for a lot of capacitors. AC interference is not necessarily important. You don't have to believe in me, because Paul McGowan from PS Audio that makes the expensive power plants claims the same in the video below.


I don't think that looks normal at all. There could be something seriously wrong with the grounding of his house wiring. SMPS should be very noisy, above 75 watts is where some have power factor correction that is not noisy. Does anybody have a better explanation?

How important is clean power?​

Who do you work for?

 

[Audiofire]

Who do you work for?

I don't work with this, but learned something about it like in this video (asked in a private message and the user really meant what my credentials are for writing on the subject).

EEVBlog #1116 - How to Remove Power Supply Ripple​

 

[FriedChicken]

I'm not worried about audio equipment getting really any interference from the grid. They have massive capacitors that will simply demolish any power line ripple.

I'm more curious how this might affect a plasma TV which AFAIK uses high-voltage DC, but I could be wrong.

 

[Doodski]

I'm not worried about audio equipment getting really any interference from the grid. They have massive capacitors that will simply demolish any power line ripple.

I'm more curious how this might affect a plasma TV which AFAIK uses high-voltage DC, but I could be wrong.

A plasma TV will use a PWM (Pulse width modulation.) power supply that will "demolish" any ripple or distortion in the incoming AC waveform. It's all taken care of in the design.

 

[NiagaraPete]

OP = fresh meat to be grilled.

 

[Killingbeans]

Most electronics then address this with a strong feedback loop, which diminishes the detail we were looking for in music in the first place.

That old song again I don't suppose you have a good explanation of how a feedback loop would have that effect?

(I know this thread has been necromanced. Sorry if OP is long gone from this forum)

 

[keantoken]

By far the main way mains noise becomes audible is through ground loops. If you hear mains noise without having a ground loop then the equipment manufacturers have done something horribly wrong, or you have a really nasty interference source and your stereo is probably not the only thing affected.

 

[FriedChicken]

A plasma TV will use a PWM (Pulse width modulation.) power supply that will "demolish" any ripple or distortion in the incoming AC waveform. It's all taken care of in the design.

I figured as much, especially considering I have a Pioneer Kuro and not anything cheap, that will have high quality components in the full stack. The AC in my house is clipped at the top end from the switching power supplies, but I don't think any power conditioner will fix that, only an AC regenerator or a dedicated line.

 

[Doodski]

I figured as much, especially considering I have a Pioneer Kuro and not anything cheap, that will have high quality components in the full stack. The AC in my house is clipped at the top end from the switching power supplies, but I don't think any power conditioner will fix that, only an AC regenerator or a dedicated line.

@amirm has performed extensive tests with very very distorted AC power supplied to a test unit(s) and the result was that even with very distorted dirty AC power the power supplies of the test units where more than capable of smoothing out the AC waveform when creating DC. For a PWM design that dirty AC power becomes even less of a issue due to the manner in which a PWM power supply operates.

A regen unit is very handy for a metrology lab where parts per million accuracy are required in measurements. For home use even with high end audio gear it's snake oil.

 

[FriedChicken]

@amirm has performed extensive tests with very very distorted AC power supplied to a test unit(s) and the result was that even with very distorted dirty AC power the power supplies of the test units where more than capable of smoothing out the AC waveform when creating DC. For a PWM design that dirty AC power becomes even less of a issue due to the manner in which a PWM power supply operates.

A regen unit is very handy for a metrology lab where parts per million accuracy are required in measurements. For home use even with high end audio gear it's snake oil.

There have been reports of a dedicated line producing better sound for amplifiers. I think maybe the outlet got starved or something? At least according to this guy:

 

[Doodski]

There have been reports of a dedicated line producing better sound for amplifiers. I think maybe the outlet got starved or something? At least according to this guy:

If the AC mains line is loaded down due to peripheral loads around your home/audio setup then the incoming voltage will be reduced and then the total voltage output of the linear power supply will be reduced accordingly.

For a PWM power supply they have a inherent advantage of being able to compensate for a reduced incoming voltage level and so there will not be a reduction in the voltage(s) supplied to the component from the PWM power supply.

I never watched the video. I have seen several of his videos and he is apparently gifted with golden ears and nobody else can hear stuff like he does. He's full of it. Snake oil salesman....

 

[FriedChicken]

Wouldn't surprise me.

I do sometimes worry about how much current I draw from my system when I've got the 60" Kuro, the M65 Amp, the RX-A810 receiver, and various peripherals all plugged into the same outlet, although it is wired for 20A.

 

[Doodski]

Wouldn't surprise me.

I do sometimes worry about how much current I draw from my system when I've got the 60" Kuro, the M65 Amp, the RX-A810 receiver, and various peripherals all plugged into the same outlet, although it is wired for 20A.

If you where exceeding the main AC circuit's parameters then the circuit's 20A breaker would trip. If you are curious about power draw then get a power meter from Home Depot and check it.

 

[Chrispy]

There have been reports of a dedicated line producing better sound for amplifiers. I think maybe the outlet got starved or something? At least according to this guy:

Why on earth would someone follow this guy's lead?

ps I've tried his videos before, find him more doofus than helpful

 

[Audiofire]

I do sometimes worry about how much current I draw from my system when I've got the 60" Kuro, the M65 Amp, the RX-A810 receiver, and various peripherals all plugged into the same outlet, although it is wired for 20A.

It's basically not the problem. As mentioned, the circuit breaker would trip if the amperage gets close to where the power cables could overheat. The problem is actually something called power factor, and the way some devices draw current in a non-linear way (also called peak current). The AC mains is supposed to be a pure sine wave and some devices use power factor correction to imitate that.