PS Audio Noise Harvester Video Review

[amirm]

I wonder if posting the original review and blocking comments on the video thread would drive comments to YT where they would boost your status in the search and recommendation algorithms.

I think we will organically get there without doing anything like this. Yesterday we were #3 on youtube. Today we are #2:

 

[Helicopter]

This video has a lot if views in a short time for sure, but more comments over on YT will still help. No reason not to go for exponential growth. I don't see any reason these should have less traffic than any other top audio reviewer in the long term.

 

[milosz]

It might be useful to do a literature search and a little original research to learn what are the most common "noises" on an AC power line, then generate an AC line with those noises on it, use the line to power a few audio devices each in turn then measure the output of the audio device for noise, distortion, etc. Also do an A/B/X blind listening test to see if "audiophiles" (also musicians, recording / mastering engineers, etc) can hear these noises in the output of a DAC or amplifier in a statistically meaningful way. I am guessing that one would be unable to hear any of this in the output of a properly engineered DAC or amp. One can often hear a crackle when some distant part of the power grid takes a lightning strike, or through induction when there is a close-by lightning strike but that's not what we are talking about here. With these power products we are interested to see if there is some subtle-yet-discernable noise or artifact that mars the "deep black background" etc of an audio system, or in some way causes distortions of the music signal being played back. One can run all the graphs one wants to show that noise is or isn't present, but scientific listening tests are the best proof of these kinds of pudding. If you can't hear it, then nothing else matters.

 

[Francis Vaughan]

John, do you mean built on stilts? Why? Flooding, or snakes, spiders and kangaroos?

John is a Queenslander, and clearly lives in the classic house style of the same name.
https://en.m.wikipedia.org/wiki/Queenslander_(architecture)

Flood and ventilation are probably the main advantages. Curiously I live in a pole house too. But mine is a design used for the side of a steep hill. Previous owners rebuilt and eventually a cellar appeared against the hill at the bottom of the stack.
Queensland snakes will climb poles. But they won’t kill you. Down here they don’t climb but will kill you.

 

[amirm]

It might be useful to do a literature search and a little original research to learn what are the most common "noises" on an AC power line, then generate an AC line with those noises on it, use the line to power a few audio devices each in turn then measure the output of the audio device for noise, distortion, etc.

I have a lab AC generator which can simulate crappy dimmers that chop of AC. Plan to do measurements with it as AC distortion doesn't get much worse than that.

 

[Addicted to music]

Interesting if the device was opened up as a tear down to see what makes that LED flash

 

[solderdude]

The noise harvester provides a small 'load' to the mains above 500Hz for differential mode only.
Differential mode is a voltage between L and N.
It does nothing for the more common 'common mode' noise.

Why is it a rather pointless device when used in audio ?
This is simple. The AC and all of its noise is filtered way more effectively by the rectifier and smoothing (reservoir) caps that ALL audio equipment has.
It has this because audio electronics internally runs on DC voltages.

Consider that only during a short time period mains 'power' is just 'restocking' the reservoir caps and the rest of the time the input voltage is 'not connected' electrically.
Have written something about rectifiers to illustrate real world effects. Do note that the load was rather substantial and the transformers were a bit 'light' for that duty. This was done so the effect would be shown more clearly.
For your typical DAC currents and DC ripples are MUCH smaller and 'on' time is much shorter.

In any case the 'garbage' on the mains will just be some little bit of 'extra' power used to load the smoothing capacitor. The stuff happening below the top of the sine wave will not be making it into the electronics.
Consider that in almost all cases (power amps exempt) the smoothing caps are followed by regulators to remove the existing ripple much further.

I think the idea of the 'harvester' (which only harvests money for PSaudio) is based on the idea of the John Lindsey Hood 'ripple eater' (a circuit that lowers ripples/noise on DC lines by shunting AC components on DC lines only instead of the more common shunt or series DC regulators.

Except:
A currents are bigger on mains
B: as mains is AC you can only get it to do something at higher frequencies because you don't want it to work in the frequency range where the power is.

How much 'power' can you dissipate in a low current LED ?
Despite the 'talk' claiming it dissipates the power it only does so for the lowest currents. Higher currents are 'clamped' by other components by the way.

Does it lower some of the frequencies above 500Hz ?
Sure it does (a little)
Is it relevant ? No

 

[Addicted to music]

someone else questioning the device

 

[solderdude]

Interesting if the device was opened up as a tear down to see what makes that LED flash

http://collinsaudio.com/Prosound_Workshop/Noise_Harvester.pdf

The red block on the left is a toroid which doesn't do much for mains frequencies. For that one would need a different core.
The capacitor also works as a high-pass ensuring mains frequencies as well as the more powerful harmonics don't make it in the electronics behind it. It will 'start' to become a lower resistance the higher the frequency becomes. At 500Hz it still doesn't 'do much' but at 10kHz to 10MHz it will.

The blue block is a transzorb that 'clamps' (basically shorts) voltages that exceed the voltage threshold and stops shorting when a lower voltage is reached.
This basically does the 'work'. It is a symmetrical device so it 'clamps' positive and negative going voltages.
So any 'peak voltage' above 500Hz and a specific voltage will provide a 'low resistance' to those signals.
Of course the resistance of that path differs per frequency as the capacitor and transformer also have a resistance.
It thus won't remove the complete 'noise' but will lower it. That is why paralleling the devices 'works'
Use 2 and the load will be double that. To double the 'load' to the noise again you need 4 and again you need 8...
However, the energy there (above 500Hz in 'differential mode') is very low and may not even exceed the clamping voltage of the transzorb.
To still 'show' there is energy there (that really isn't clamped at all) the orange block is needed.

The orange 'block' is the so called 'harvester' part. A harvester kind of 'collects' energy. The diode (probably a Schottky diode) in the blue block will charge a small capacitor with the 'energy' (very low in power) and thus those small amounts of 'energy' are 'added' to the capacitor until a voltage threshold is reached and that capacitor will be discharged through a very efficient low power blue LED. The more energy it will receive in a specific over time the faster it will blink. A blue LED will light up on less than 1mA and as the blink is short the overall energy needed to make it blink is VERY low. After the LED 'flashed' the 'harvesting' process repeats again. The block schematic shows 1 diode but it looks like there are 2 of them that form a full wave bridge rectifier.

That harvested 'energy' is what makes the light flash. It is an indicator not the actual part that removes or dissipates the heavy lifting energy.
The 'heavy duty' parts (that raise the temp inside) is the transformer (which also dissipates the mains harmonics a bit) and the transzorb. The LED is merely an 'indicator'.

HF crap is not differential mode (in general) but common mode. The harvester does nothing for that as it only can do something differential mode.

Differential mode = a voltage between Live and Neutral.
Common mode = a voltage between the Live (and Neutral) and ground. A common mode signal thus will have the same amplitude on both the L and N wire and thus is not differential (no signal between L and N).

 

[egellings]

An experiment to do would be to plug two of the harvesters into the same duplex outlet, side be side so that both get the exact same signals, and see if they blink in unison or blink independently of each other. If in unison, I'd be more likely to believe that they are responding to something on the line. If they blink independently, willy-nilly, then I don't know what to think.

 

[Lambda]

An experiment to do would be to plug two of the harvesters into the same duplex outlet, side be side so that both get the exact same signals, and see if they blink in unison or blink independently of each other. If in unison, I'd be more likely to believe that they are responding to something on the line. If they blink independently, willy-nilly, then I don't know what to think.

Count the blinks per minute and look if it goes down by adding more harvesters.
If so you can extrapolate how many harvesters are needed to get to an acceptable blink rate.

 

[SmackDaddies]

In this case, I'm sure what a 'ground' is. But to add a Safety Ground would require replacing a 2 wire cable, with a UL approved 3 wire cable all the way back to the main breaker panel.
Note that the connection to Planet Earth has nothing to do with day-to-day AC power quality. It's there for safety during unusual events.

well...no. You can run a ground wire from any circuit that feeds the same panel. So if you have a good ground connected back to the panel, you can connect a separate ground wire to an existing outlet, and swap the old 2 prong outlet with a grounded outlet.
https://www.jadelearning.com/blog/replacing-two-wire-receptacles/

 

[Jerry Sobel]

So if audio component companies that sell a lot of different products sell something like this device which I consider to be fraudulent then how can you trust that anything else they sell is what they say it is?

 

[Lambda]

then how can you trust that anything else they sell is what they say it is?

You can't!
Thats why i don't buy from company's that sell snake oil

 

[Purité Audio]

Actually a really quick and easy way to determine if a manufacturer has the slightest shred of integrity/honesty.
Keith

 

[Lambda]

Actually a really quick and easy way to determine if a manufacturer has the slightest shred of integrity/honesty.

What if a doctor prescribes placebo (and it helps)?

 

[Purité Audio]

What if you just stick to manufacturers that make really good equipment with no BS.
Keith

 

[Lambda]

What if a view dB more SINAD don't bring joy to the customer but a blinking box (with a nice story) dose.

The problem is selling Placebo without telling the customer is unethical.
But on the other hand you can't say you sell Placebo or they don't work.

 

[ta240]

Every time I see snake-oil products from a company, that puts a sour taste in my mouth, and makes me question their entire business practice.

To me the 'affordable' snake oil like this is much worse than the stuff priced the same as a family sedan because this often takes money from people that don't have it to burn. I glanced at their site this morning and found they sell a $130 power cable that is 'specially designed' to match with their $700 sprout amp. There are likely people out there with $130 in power cable and a couple hundred in interconnects and another hundred or two in speaker wire connected to that little 'bargain' amp. Instead of spending $1,100 on a better amp or putting it towards better speakers they have $400 in complete junk attached to a $700 amp and that is just sad. It is like buying a $15,000 economy car and then putting $10,000 in fancy 'air' in the tires to improve the ride and performance.

 

[the_hamster 2]

In this case, I'm sure what a 'ground' is. But to add a Safety Ground would require replacing a 2 wire cable, with a UL approved 3 wire cable all the way back to the main breaker panel.
Note that the connection to Planet Earth has nothing to do with day-to-day AC power quality. It's there for safety during unusual events.

For our home office, I installed an “hospital-style” isolated-ground 15A circuit to service desktop PC, printer, and home network peripherals...never once noticed untoward noise, but not sure if this would be overkill for an otherwise dedicated circuit for stereo kit.