The 6 ways of power filtration


Well-Known Member
Mar 25, 2014
I'm no tech, but here's how I see it:

1)Capacitor/inductor/coil based (Shunyata, Audience). Simple components placed over the lines, in the hope of breaking-up noise. I don't think these worked too well. The Teflon-equipped Audience (2008) was an improvement, but at a high cost.

2)Big transformer (Silver Circle, Torus). Something else placed in the power-path and this time more effective. Still not perfect, though.

3)Sine-wave generation (PS Audio, Pure Power). Essentially a power amp and IMO trying to do too much. The reviews were strong, at the time. But some of these (reviewers) now say they're only a partial solution.

2014 -on
4)Pull-away or drain noise (High Fidelity, Entreq, Akiko, Nordost QKore). Using magnets, rare-minerals or secret-ingredients. Some of these are placed in the direct-path of the power. Others are plugged into a power-bar (alongside the components) or into a component's rear ground plug.

5)Balanced power (Equi=Core). It's been tried before, but only in the last few years has it been good enough to get talked about.

6)Re-chargeable power tank (Stromtank, Tesla). It's not a big battery, it doesn't contain the chemistry associated. Great for reserves, but needing an inverter, it's unclear how it removes the noise that came when charging.

Added 7)Low-frequency pulses (that 'tune' electrical fields -Nordost QRT, ADD-Powr)

Hybrids (Audioquest Niagara, Synergistics). Pull noise out, then add reserves.
Last edited:


Oct 26, 2015
Eastern WA
1. These work very well for removing noise. But they are usually designed very poorly for audio playback. There is no question that measured noise is reduced, if there was all passive speakers with a crossover would be giant piles of shit that didn't work at all because they use the same type of parts. Also Teflon capacitors have higher 3rd order distortion.

2. They aren't all made equal! They are very effective for noise but not always audio playback.

3. At least these can be power factor corrected, but how low is the noise or what they impart on the audio? Good question since swapping the incoming powercord on them can make it sound like swapping stereos. But they do excellent things for people in areas with very poor power that's spotty.

4. Ha, those don't decrease noise they increase it. Facts of physics as we know them. That doesn't mean you won't like them, many people do.

5. Been around a long time. They work well for certain types of noise, but not necessarily anything audio specific. Are they worth it? That's up to you. They really don't do much more than an isolation transformer for audio.

6. I've wondered, too, but as far as I can tell it works just like 3 when connected.

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