September 29, 2009

Power Of Silence. More Adventures With Audio Prism Noise Sniffer.

Audio Prism Noise Sniffer.

Over the years, many have accused high end power cords and PLCs of been useless devices with "Snake Oil" label. Are they really?

With the Audio Prism Noise Sniffer at hand, I set to find out.

Let's see what the Audio Prism Noise Sniffer results say, Refer to the chart below:

Note: All figures are represented as decibels(db). Ambient[B] taken as room's noise floor for base line comparison. Direct/Wall[C] as per reading taken direct from wall power point, unfiltered. Filtered[D] as per reading taken from Power Line Conditioner outputs or Power Cord's IEC end. Extention[E] readings are taken if any extensions are used from PLC to power front end equipments. Results[F] are taken in (-) minus readings to represent the power line noise reduction in decibels(db).

A post mortem of the results obtained.

Based on the Results[F] columm figures, it would appear that the PS Audio Power Plant Premier regenerator is the most effective in cleaning up EMI/RFI noise riding along power lines, by reducing a whooping -62dbs from the 112db reading taken direct from wall. This means that the output of the PS Audio PPP is dead silent taken in to consideration that room ambient is 50dbs, when gauge from the Audio Prism Noise Sniffer's tiny speaker.

Coming in joint 2nd placing with -59dbs noise reduction reading is the Pure Power 1050i and the Furutech Daytona 303. My much loved Torus Power RM8A only managed a close 3rd placing with a noise reduction of -58dbs. As to why the other Torus Power RM8A only managed to reduce noise by -51dbs? That has to do with the point in time when I took the powered measured from wall, which only read 105dbs. The results would have been much the same as mine should the noise from wall taken at that time been noisier, say at 112dbs?

Furutech Daytona 303.

Torus Power RM8A.

PS Audio Power Plant Premier.

However, the results above are just one of the few aspects of noise reduction measurement, in relation to what we actually hear via our hifi system. I must stress that the chart above alone is in no way a justification of which is the best PLC available in the market. The chart above should instead, I feel be taken as a guide to help you narrow down your choice of PLC for audition in your system.

Based from the above chart, there are ten facts that stood out quite clearly.

1) All transformer based PLCs, irregardless of brand, will leave a some residue noise, on both the Torus Power RM8A units measured, there was a consistent 2db transformer hum at output, I would consider that as the best of the transformer based PLC breed measured.

2) The Audio Magic Stealh XXX, PS Audio PPP, Pure Power 1050i and the Furutech Daytona 303 deserves special mention here as their results were total silence, i.e. total noise elimination. Though the Audio Magic Stealh XXX measurement results only showed -42dbs, one must note that it started with only 92dbs of noise measured from wall. I am sure if the wall measurement was noisier, say 112dbs, we would have got a very diferent results, which I am very confident that the Audio Magic could do much more than this survey had indicated.
Audio Magic Stealh XXX.(photo is an older model)

3) Any sort of power cord extensions, used post the PLC's output, is sure to act as an antenea for EMI/RFI noise. In my own case, the noise picked up along the 10ft of cable extension post Torus Power was +17dbs! In the case of the Subang Jaya, all Furutech based system, the 12ft extension used post Furutech Daytona 303 was +12dbs, indication that the Furutech Evolution power cord used for that extension is superior compared to my rather economical JPS Inwall, in terms of noise sheilding.

4) Low cost power line filters like the Audio Prism Quiet Line MKIII(-30dbs noise) and Isotek Isoplug(-19dbs noise) are more effective than I had imagined. However, the trick is to install them as close to your equipment as possible. They do loose their effectiveness rapidly with more distance. For a mere RM$200-300/pc, they are PLC bargains when used correctly, and great for first timers starting out in the PLC journey.

5) Exotic and high price power cords actually do make a diference, irrespective one can hear it or not, the Audio Prism Noise Sniffer can tell the diference! The most expensive power cord of the group measured, the JPS Kaptovator, priced at RM$5K+/per meter can reduce power bourne noise by -18dbs! On the contrary, the typical standard power cord supplied with most electrical appliance and hifi equipment picks up +6dbs of noise along it's 1 meter length! Along the way, we have Shunyata, PS Audio amongst other specialty power cords available in the market, effectively reducing an average of -6dbs of power bourne noise along it's one meter length. Does that give you something to think about?

6) Small tweaks, like an X-2 capacitor, installed on the IEC end of my JPS Inwall power cord, does reduce noise by as much as -4dbs! As measured on two of my identically terminated JPS Inwall, one with the X-2 cap tweak and the other without.

7) Dimmers are an absolute NO-NO!, in a hifi room, note the system where the PS Audio PPP resides and had a dimmer light switch installed, with the dimmer in use, the effectiveness of the mighty PS Audio Power Plant Premier is reduced to a mere -14dbs, from the previous -62dbs when the dimmer switch was not in used.

8) Good plug points and contacts can also reduce noise by as much as -2dbs! This was demonstrated between the use of the much supperior built Isotek Multiway vs the cheap 'n' cheerful Wireworld Electrifier in my system.

9) Though results were unlisted, and I do not have concrete proof of what I am about to say. I believe that economically priced digital gear are more prone to digital power supply noise bleed back in to the system power supply, compared to the higher end models. This was demonstrated when I plugged the Stello CDT-100 and DA100 Signature pair in to the Wireworld Electrifier, sans the Isotek Isoplug filter, I found the noise floor from the output of the Wireworld Electrifier to measure at 73dbs, vs my resident Marantz CD7, which measured at 71dbs, same as in with or without the Marantz CD7 plugged in. There was a 2db noise floor diference in favour of the more expensive, if older Marantz CD player. Reason being, I guess is that the higher end CD players have stiffer and better filtered built in power supply modules, compared to the economical model.

10) The RGPC 400 Pro, is perhaps the most misunderstood power product by the consumer. In used, either as part of the RGPC Isogray or as a stand alone product to power a hifi system, it consistently reduces only -1db of noise. I feel therefore, a need to clarify the purpose of the RGPC 400 Pro. It's not a power noise filter. It's intended more of a power storage and peak power draw smoothening device. The RGPC 400 Pro will store up to 2000W of power, and when required, can release all those energy in an instant, as it is usually installed much closer to the hifi system. My guess is the the -1db noise is more a result of good contact then anything else.
Pure Power 1050i.

One final thought I wish to add to the Noise Sniffer Results chart above. Whilst the regenerator type PLCs technically reign supreme in this simple but high effective Noise Sniffer test, it doesn't quite tell the whole story. If you'd look back at my previous reviews of the Pure Power 2000 PLC, which is regenarator based on class D amplification technology, you'd read about my mentioning about it's sinewave output profile of a saw tooth like pattern. This saw tooth like pattern, mostly emiting 3rd order harmonics, which are some what less pleasant to the human ear perception, much like why some audiophiles prefer tube amps over solid state. I do believe that the current PS Audio Power Plant Premier is class D based as well, compared to it's older models.

With this final analysis, my time with the Audio Prism Noise Sniffer had come to an end. Did you notice how much A/C power supply infomation, one can get from this little device, with aide from an SPL meter and a little thoughtfulness?

The Audio Prism Noise Sniffer is an essential tool if one is serious about experiencing how power supply noise issues effects our hifi system's performance.

Audio Prism products sold by Hi-Way Laser, contact Kenny, tel:019-2813399.


maggielurva 愛美姬 said...

big E,

thanks for the thoroughly researched post.

for me, the PLC can reduce noise as much as i care but if it impedes the music (and does not sound musical), then it won't pass my test.

so, noise reduction is not the be all and end all of PLCs. to me, at least.

just my two cents.

Big E said...


I understand you thoughts very well. That's why I asked readers not to take the chart results for buying decision, but rather as a guide to shortlist amongst the more technically competent candidates. The chart results only tell part of the technical story.

Do listen to the compatibility factor with one's set up, I am sure with all those products out there, there should be at least one that fits.

Remember, music first!

mikelau.2 said...

Big E,

"Remember, music first !"
It will be interesting for you to expound to us your understanding of SOUND & MUSIC ? One cannot have 'good' music without first achieving 'good' sound, right ? Much as I would like to put MUSIC first it always goes back to SOUND first. And, much as you would like to lay emphasis on "music first" your blog & blog title and reviews are skewed towards SOUND qualities. Not that its wrong, but, its SOUND first ?


Big E said...

Mike Lau,

Good question, can my reply be this?

They'd be no sound without music?
Non musical notes are just sound?
Noise make us sick?
Silence is as precious as the golden pound?

Sleep over it. He!He!

mikelau.2 said...

Big E,

heh heh.."They'll be no sound without music ?" Isn't it the other way round ?