Noise harvesters--zapping noise at its sources, our own equipment

I’ve been discovering lately that our own equipment is a source of a high level of EMI… Of course, the electrical system spreads that junk into anything else that’s plugged into that outlet or circuit.

I bought a Green Wave Broadband EMI Meter which plugs into electrical outlets and measures noise and expresses that in AC milliVolts… The quietest outlet I found in the musicroom (MR) was one of the power conditioner’s unused outlets that measured around 50 mV… The noisiest was an outlet on the back wall of the musicroom fed by one of the house’s regular branch circuits ranging from 200 - 300mV… When I turned on the projector plugged into it, the noise jumped to over 2000mV!

I decided that since the Noise Harvesters (NHs) do NOT shunt the hot line to neutral (or earth either, since the NHs don’t have an earth pin), they’d do no harm and bought a couple used ones here… (I’d had a few many years ago but they’re long gone.) I plugged the meter into one of the p-con’s outlets that is shared with my discplayer… DP off, around 50mV.; DP on, around 400mV. NH plugged into into the same outlet as the meter, around 300mV… Obviously this is not a large decrease, but the NH certainly is absorbing SOME noise created by my equipment.

I now have my two NHs plugged into each outlet feeding my (highly digital) preamp and my Oppo '203 discplayer… As more NHs arrive, I’ll add them to outlets on noisy lines… As Paul has indicated in a response somewhere on this forum, and I paraphrase, more Noise Harvesters in the lines means less noise in the lines…

That CAN’T be bad. … :grin:


What I would like to know: How to use Noise Harvesters in conjunction with the DirectStream Power Plant equipment… Like put one in front of it or behind it or none at all…?

As Paul has written previously, using one before a regenerator (RG) would help; after, not so much…EXCEPT…an NH plugged into the same group (zone) of outlets that is feeding digital equipment and that are NOT isolated from each other certainly would reduce noise among equipment sharing that zone or outlet… I’m fortunate in having more p-con outlets (ALL in common with each other in my current BPT p-con) than p-cords feeding equipment, so I can plug an NH into every duplex outlet.

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Clear as a bell Jeff… Thanx…!

When plugging the NH into the outlets of the P10 they flash at a periodic rate, I asked about this years ago and Paul said the P10 emits a 10 Khz signal from the the outlets, not sure if the next gen P20 is different.

According to Paul the 10 KHz has no negative effect on SQ.

Given this 10 KHz it seems to me that would saturate the absorption capacity of the NH and greatly reduce any benefit on the output of the P10.

I can’t imagine (but I don’t KNOW) that an NH’s capacity would be exceeded by much of any kind of noise, and that 10KHz signal may not even be in the frequency range the NH eliminates… But even if either is true, the digital trash created by the components we have plugged into a p-con’s outlets(1) still gets into all the other components plugged into that zone or outlet… That’s why I’m concerned with isolating or removing that noise… In a, say, P20, I’d have an NH plugged into each zone, just as I’ll have NHs plugged into EACH outlet (that’s feeding a component) of my BPT 3.5-Ultra Imp. balanced-power p-con.

Maybe Paul will opine for all our benefits. … :thinking:

(1) unless EACH outlet is filtered both inductively and capacitively as they are in audience’s larger p-cons.

This topic is of great interest to me, as I have five Noise Harvesters and two P20s with lots of spare/unused duplex connectors/outlets. Please continue to share your observations!

I’ve done further test using a GREEN WAVE Broadband EMI Meter, and the measured noise has NEVER gone up when I’ve added an NH in that outlet, and almost always the noise measurement goes down, and sometimes way down, after adding an NH… I now have 11 NHs, plugged into each of the (all-in-parallel) duplex outlets of my BPT 3.5-Ultra powerconditioner and also into the outlets around the music room that are driving mostly digital devices such as my projector and cablebox.

I’ve ordered a P20 that should ship NLT than May 03; we’ll see how that goes, generally, and in respect of the NHs.

Another point on the P20.
I understand–and someone PLEASE correct me if this is wrong–that each outlet WITHIN a Zone is in parallel and NOT isolated from any other outlet in that zone… If this is correct, then the noise generated by my DP, for instance, would contaminate the input of my highly digital preamp if they’re plugged into the same zone… (I believe I’ll call that ‘cross-contamination’ hereafter.)

I have four cables to fill the High-Current zones, so I won’t be able to add any NHs to the P20 to prevent cross-contamination… However, one of these HC cables is a 12g. ‘extention cord’ that contains two duplex outlets and feeds two plateamps for my Super-7s’ woofers, and I can add an NH to each duplex outlet to reduce some of the combined noise appearing in that zone… So I guess I’ll plug each of my main-poweramp p-cords into Zone E’s duplex and my third (CC and surrounds) poweramp and this extention cord into Zone D’s duplex. Then I’d plug one or two NHs into the extentioncord’s two empty outlets… Since the two duplexes are in parallel, I can plug the noisemeter into one outlet and then an NH into the other to see if the amount of noise decreases. :slightly_smiling_face:

PSA people, pls tell me if this approach makes sense or if I’m wasting my time (and a little money).

P20 was shipped today April 26 and is scheduled to arrive Tuesday April 30th. :slightly_smiling_face: :grin: :smiley:

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I think you worry too much. I have no Noise Harvesters on my P20 and I still hear good things.

EDIT: plus you do not have to fill the high current zones. You could just use one of the two outlets in each zone to remove the possibility of cross contamination. As I understand it the output of the HC zones is the same as all others.

You’re probably correct about worrying.

If the HC outlets are fed the same as the other zones’ outlets, why are they called ‘HC’?

I believe the difference is in the way they are switched on. Hopefully someone will spell it out correctly.

There is some sort of surge/in-rush delay/protection on the HC outlets. Same specs., just an additional safeguard for HC kit. Reportedly, the HC outlets have limiters that kick in when a piece of equipment draws a large amount of power on power-up.


"Hi Jeff,

Good question. The HC outlet is a little different because upon turning on, the HC outlets will prevent the inrush current from pulling too much current right when the gear is switched on. As far as the power coming out of these zones, they aren’t any different.


James Herod | HiFi Advocate
1-800-PSAUDIO direct 720-402-3926 Boulder, Colorado"

I then asked two questions about outlet isolation.