Measuring line noise and power conditioners


I recently purchased a Trifield EMI (Dirty Electricity) Line Meter to measure noise coming from my outlets. To my surprise, my $500 power conditioner (name withheld to protect the potentially innocent) appears to not filter any noise per the Trifield readings. In fact, with some of my outlets the measures are higher through the conditioner’s outlets, than the measures coming straight out of the wall. The manufacturer denies anything is wrong with their conditioner, claiming the Trifield is measuring the wrong frequencies. Can anyone explain?

output555

Showing 3 responses by cakyol

Power conditioners are all snake oil and are NOT needed. The only useful purpose they may serve is for dangerous voltage protection like lightnings and such.

All amplifiers work with DC. Mains AC is converted to DC inside all amplifiers thru transformers, rectifiers, hi freq filters and smoothing capacitors. Lower wattage power amps may also have voltage regulators, which is even better. Because of this, the quality of the mains AC has virtually NO effect on the sound (the DC) if the amplifier is properly grounded and there are no ground loops. If the rectifier and smoothers are of good quality (which in most cases these days are), and proper spike filtering is also done (again, which in most cases these days are), and as long as the waverform you feed into the transformer from the mains resembles ANY kind of rough sine wave (which will be the case even in the noisiest mains supplies), everything will be fine. You may run LESS EFFICIENTLY since the transformer will not establish a proper magnetic field but the rectifiers & smoothers will take care of everything.

ALL the necessary design to make the DC as smooth as possible are ALL included in the amp itself. Noise reduction, PSSR, smoothing, ripple reduction and transient current capability are ALL included in the power supply of the amp itself. Especially with good quality amps, this is almost always a given (Like Pass Labs).

Where you need a good quality clean AC is if you are using AC motors, like synchronous and induction. These may be driving your turntable and their rotational stability and "jerkiness" is directly affected by the quality of the AC. Even then, most turntables these days internally synthesize their own AC thru precision electronics if they are using an AC motor (one of the earliest example of this is the Linn Sondek LP12 Valhalla).

Therefore, power conditioners are a complete waste of money for amplifiers.


LOL.... Everyone missed my point. I never argued about the EXISTENCE of noise. I simply said it is ALREADY taken care of inside the amp itself. Almost all decent amps today deal with it internally. There is NO need for an external noise filter.

And here is a small article for your education:

https://www.eetimes.com/bypass-or-decouple-your-way-to-power-supply-noise-reduction/

And here is another one. Read page 3 especially:

https://www.ti.com/lit/an/snaa057c/snaa057c.pdf?ts=1592043954950&ref_url=https%253A%252F%252Fwww.google.com%252F

Note that all these methods ALREADY exist in all decent amps costing more than about $1k and the filter components cost about 30 bucks at most.

And here are some examples of IEC inlet filters, a FEW bucks each:

http://www.radiuspower.com/emi-filters/iec-inlet-filters

What do you think are inside those expensive power conditioners LOL ?
Open one up & see one day.


Mickeyb

Are your 2 systems identical and room acoustics and speakers exactly the same ?