When to use/how to choose a power conditioner

[RayDunzl]

anybody ever measured noise on their AC mains to see if they need one?

Mains are always noisy.

Your own gear puts in spikes as the rectifiers turn on and off, and the power draw flattens the peaks creating harmonics, along with everyone else's draw on your utility's local transformer.

Measure your outputs to see if it actually creates a problem.

 

[MRC01]

anybody ever measured noise on their AC mains to see if they need one?

There's always going to be some AC line noise. A good piece of audio gear having a well filtered power supply will squash a certain amount of noise. So just because there's some AC line noise doesn't mean you have a problem. How much noise is too much? It seems like you'd have to measure not only your AC mains to quantify how much noise is there (which will vary day to day and time of day), but also measure the output of your equipment to see whether any of that noise is getting through.

 

[NTK]

anybody ever measured noise on their AC mains to see if they need one?

Here is an article I remember reading a few years back. The motor drivers for the newer appliances that use energy efficient BLDC motors (air-conditioner compressors, fans, washing machines, etc.) can back-feed a lot of noise into the AC mains.
https://www.edn.com/why-is-everything-junk-heat-pump-edition/

 

[Wes]

There's always going to be some AC line noise. A good piece of audio gear having a well filtered power supply will squash a certain amount of noise. So just because there's some AC line noise doesn't mean you have a problem. How much noise is too much? It seems like you'd have to measure not only your AC mains to quantify how much noise is there (which will vary day to day and time of day), but also measure the output of your equipment to see whether any of that noise is getting through.

Seems like you should be able to characterize a noise level that will not significantly affect HiFi gear, then see if it is above that level or not.

Or is HiFi gear that variable?

 

[MRC01]

Audio gear of different types from different manufacturers is highly variable in the quality and filtration of the power supplies. Some are over-built like military equipment, some are so cheesy you wonder how it works at all, others after seeing how they're built you might never plug in again due to risk of fire or explosion

What makes this even more complex is that even if the audio gear isn't performing to spec, it doesn't necessarily mean the AC line noise is the cause. It seems to me one would have to measure both AC line noise and equipment output (record the signal and compute an FFT) together at the same time, on different days at different times. A power conditioner makes sense as a solution only if the gear is out of spec and it happens at the same times the power shows high levels of noise. Otherwise, a power conditioner is just an expensive solution looking for a problem.

 

[trl]

anybody ever measured noise on their AC mains to see if they need one?

Mains AC - 230V measured with an 230-115V converter (a coil/inductor placed in series)

Same as above, but with a low-quality (probably defective) SMPS in the same outlet (notice the THD increase due to the DC added on top)

Noise measured between Null and Earth when vacuum runs (it is pretty close to zero without vacuum cleaner)

​

Most of the time I prefer to use an isolation transformer (a cheap one) to my audio stuff (not to my speakers amp) because there's some filtering that is done by the transformer, also the removal of the DC coming from the bad switching supplies (if exists nearby). Also, if a poor SMPS gets inserted into the outlet from the outputs of the transformer, then there's going to be a strange noise coming from transformer's coils, so it's easy to troubleshoot which SMPS is not OK and which one is not.

However, YMMV.

 

[RayDunzl]

Noise measured between Null and Earth when vacuum runs (it is pretty close to zero without vacuum cleaner)

I used to worry about the ugly waves on Neutral to Earth.

Now I have a nice 60VAC sine on my neutral, in opposite polarity to the 60VAC sine on the Hot line.

If that doesn't cause a problem, well...

 

[trl]

I used to worry about the ugly waves on Neutral to Earth.

You might want to measure the DC voltage too, because if it's because 50V, then a Type-A or Type-F RCBO/RCCD might be needed, instead of the cheap usual one Type-AC that can't protect over the DC pulsating currents that could get injected by a bad SMPS. Although, not sure the 115V can actually do any injury to a grown up adult.

 

[Abe_W]

My "power conditioner" is an Equitech 1.5Q balanced isolation transformer.

View attachment 37383

The raw A/C power here likes to make the transformers in my amps audibly groan, this stopped it.

The output AC floats around the earthed center tap of the secondary.

Hot and Neutral are at 60Vac (differential).

It also silenced all the other transformers in the rack, now only faintly audible by using a stethoscope on the enclosures.

I will be electrocuted by it at some point still in the future, according to urban legend and conspicuous and repeated warnings here at ASR. Let me add a pre-need Good bye, Farewell, and Ta-Ta.

Besides, if it's good enough for LIGO, who am I to demur.

How close do you get to this unit's max rated VA with different devices plugged into it?

 

[RayDunzl]

How close do you get to this unit's max rated VA with different devices plugged into it?

It's impossible for me to accurately assess the demand on that 1800W outlet without a peak-reading ammeter.

If "peak" demand from product specs is the guide, I'm way way over.

If I measure the current at the single wall outlet, a few hundred watts is typical during a high demand session.

Roughly:

2 x Krell FPB 350 mcx = 3400W - 200W idle and ramps up (Plateau Bias is the trade name) with demand

Add preamp, TV, cable box, EQ boxes, player boxes on the Equitech

And on the same branch add all the accoutrements for a power hog desktop PC and printer and router and modem etc.

My analysis:

It 's not a problem. I bought the goods to run a 20A dedicated circuit to the entrance box but never found reason (measurements) to install it (or have it installed)

Or, it's not a problem unless I try to run the vacuum cleaner too (oops), and the overhead kitchen lights (8 flourescnet tubes 200+ watts) which for some reason are on the same branch.

 

[Abe_W]

It's impossible for me to accurately assess the demand on that 1800W outlet without a peak-reading ammeter.

If "peak" demand from product specs is the guide, I'm way way over.

If I measure the current at the single wall outlet, a few hundred watts is typical during a high demand session.

Roughly:

2 x Krell FPB 350 mcx = 3400W - 200W idle and ramps up (Plateau Bias is the trade name) with demand

Add preamp, TV, cable box, EQ boxes, player boxes on the Equitech

And on the same branch add all the accoutrements for a power hog desktop PC and printer and router and modem etc.

My analysis:

It 's not a problem. I bought the goods to run a 20A dedicated circuit to the entrance box but never found reason (measurements) to install it (or have it installed)

Or, it's not a problem unless I try to run the vacuum cleaner too (oops), and the overhead kitchen lights (8 flourescnet tubes 200+ watts) which for some reason are on the same branch.

Understood.. It is a bit of a relief to hear you're not too concerned about going over product spec demand as well...I am in a very similar boat. I guess i could find/ borrow a peak ammeter at work and check things out a bit for more peace of mind. Thanks.