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PS Audio Noise Harvester AC Cleaner Review

Vini darko

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#61
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#63
So, we stick a parallel filter across our mains supply, in the hope of filtering out the noise on the entire circuit...?

Think how much power is available from the power grid coming in to your house supply. Think how little that supply is bothered by you sticking your 30kW or so load on it. Think of just how much noise power there is on a mains circuit, and what the impedance of a mains supply is. That noise is caused by power circuit switching, and high current machines. So you're not going to clean up your entire house wiring with a capacitor and an LED; you would have to dump all that noise power into a dissipator.

If you want to filter noise present on your house wiring, you do it with a series filter, in line with the supply to the equipment. Ideally, fitted as standard to the equipment by the manufacturer. That's what proper electrical equipment manufacturers do.
 
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#65
The other company with as much audiophile-claims-without-data is AudioQuest. Good thing Amir has one of their “budget” line conditioners for testing too. :)
I still feel burned for dropping $60 on AQ's "Jitterbug" which, as Amir previously showed, does absolutely nothing.

I have a Dragonfly Red and though it was far overpriced I do find it useful. But won't be buying anything from AudioQuest again in the future. Audio companies that put out pure snake-oil products, even if they produce some other good equipment, are companies I want to avoid.
 
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amirm

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Thread Starter #67
Now I want to see some furman products reviewed!
Since that is a surge protection device, it would require specialized test gear to measure those specifications. But for noise filtering of audio products, yes, we can do that easily using this new protocol.
 
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#70
Since that is a surge protection device, it would require specialized test gear to measure those specifications. But for noise filtering of audio products, yes, we can do that easily using this new protocol.
I'm more interested in the conditioning aspect anyway. That would be great. I have a furman PST-2+6, but I dont really think it does much. Some of the larger behemoths use a gigantic toroid and a bunch of other RF filters.


1592333987097.png
 

DonH56

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#71
These things all ignore the noise rejection built into every power supply of every component made.

The one thing I could imagine of benefit is to reduce the charge kick on the line from SMPS' that are in widespread use since many seem poorly designed and without PF correction or input filtering. I can also imagine measuring a change but with zero audible benefit.
 

GXAlan

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#73
I am of the belief that DC blocking is the only "line conditioning" that may have an audible effect for those with transformer hum caused by DC on the line.

The Noise Harvester is good for showing how the inefficient PS Audio Power Regenerators (basically amplifiers) can provide cleaner AC power (no flashing). But it will be interesting to see if going from 3% AC THD to 0.1% AC THD translates into something measurable. Someone needs to submit a PS Audio or Accuphase AC regenerator for review.

@amirm, will Gig Harbor Audio lend you any additional Accuphase gear for testing? They have a line conditioner that an correct the flattened peaks you describe. Or was the lukewarm E-270 "review' the nail in the coffin?
 
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amirm

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Thread Starter #74
3. Does your lab powered AC supply do any better?
Yes it does. I had to use a smaller step down transformer as the other one was too big for its outlet. So I repeated the AC mains from my power strip (right) to lab generator (B&K 9801):

AC Mains BK 9801 waveform analysis review.png


You can see the difference more intuitively in time domain:

AC Mains BK 9801 waveform analysis time domain review.png


Specification for the B&K is 0.5%. So the excess amount we see here is due to instrumentation (long straight wires from transformer, etc.) and non-linearity created by the transformer in use.
 
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amirm

amirm

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Thread Starter #75
@amirm, will Gig Harbor Audio lend you any additional Accuphase gear for testing?
I am afraid not. As I expected, he got grief from his subjectivist customers so not willing to have more stuff tested the way I have been doing.
 

CDMC

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#76
I am amazed, four pages and nobody has joined the forum just to say that either 1) it works, it just doesn't show up in tests but is plainly audible, 2) Amir doesn't know how to measure, or 3) Amir doesn't know what to measure.

I have an older Monster power conditioner, switcher, with a voltage and current display. They used to sell the discontinued ones at major discounts. I never heard any difference from it, but it does what I bought it for, switching on and off my amp that has no power switch.
 
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amirm

amirm

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Thread Starter #77
While I had the B&K still powered on, I tested the Topping A90 in preamp mode with and without it as the source:

AC Mains BK 9801 with Topping A90 Generator Measurements.png


As we see, despite the B&K 9801 generated AC being much cleaner, it made zero difference in the performance of the A90!

Why? Because these devices don't run on AC. They convert everything to DC, filter the heck out of it, and then use it. In addition there is high resilience to power supply noise (PSRR).

In other words, we have proven electronic design works. :)
 
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amirm

amirm

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Thread Starter #78
I have an older Monster power conditioner, switcher, with a voltage and current display.
I have one of those but left it in our old house! Wanted to see the voltage all the time so it was good for that.
 

cjm2077

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#79
Since that is a surge protection device, it would require specialized test gear to measure those specifications. But for noise filtering of audio products, yes, we can do that easily using this new protocol.
Have you thought about getting a LISN for tests like these? That way you could feed AC to a "typical" device and look at the mains signal through the 50 ohm port without "disturbing" the original setup. I don't think it would change anything in this test, but it is the way I've always done conducted radiation testing and is what they do for standards testing like CE, UL, etc.
 

Herbert

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#80
Maybe the right moment to chime in: I am a lover of early Compact Disc Players, not sound wise
but thebecause o the built quality.
I have many first and second generation models at home.
Almost all of them have some kind of AC-"noise blocking" bevore the mains transformer,
nomally a smaller transformer and capacitors
Never marketed and advertised, never touted and scrapped in later players. Nothing "High End", Nothing anyone
spoke about 35 years ago.
I found this kind of filterig is in a Sony-CDP-101 / 103 / Philips CD-304,
Toshiba XR-Z70 and many more - what was it and why?
In the following Image, the "line filter" of a "middle class" Sony CDP-103 from 1985.
No more data on L991 in the service manual, I guess it is some kind of choke/inductor...
 

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