2. misc-audio
  3. 155291-20253

Keep noise creators outside your clean power zone

Hi Everyone,

Just a tip for those of you who have invested in power conditioners:

Keep things which generate noise outside of your clean zone.

Power conditioners, unless fully active, are just filters. They are not magic blessing devices. What I mean is that the power that comes in gets filtered, and sent out, but it can be contaminated again! It’s just like your water supply. Makes no sense to use fancy water filters, and storing it in a dirty bucket.

If you can, avoid using wall warts, and network devices like Wifi routers, switches, video streamers etc. on the clean side of your conditioner because they will contaminate the already filtered power. If you have a conditioner with multiple zones, put all your noisy neighbors on the same dirty zone.

I try to solve this by using a less expensive but still very good power strip to create a "de-militarized zone." DMZ for short. The Furman PST-8 is a great way to do this, because it does include really good filtering which goes down to about 3 kHz.

Plug it directly into the wall, not into your conditioner. This will give you the most number of filters between your wall warts and your audio. Of course, other alternatives are to use linear power supplies exclusively, but even then, anything with a network or CPU in it can generate noise that makes it through the power supply.

Lots of other conditioners will work, of course, the Furman with SMP just has great noise handling and ~ $120 is much more affordable than alternatives.

Whatever you do, keep your noisy neighbors outside your clean zone.

Best,

E
erik_squires
erik_squires OP
16,180 posts
 
Erik, is this a manufacturer claim or has there been some independent testing?   I am not doubting it, just curious where the number comes from.

@heaudio123

Good question, and I actually had to think about where I got this number from. it's actually inferred from similar technology. Series mode surge suppression needs a big low pass filter to work. That filter is in place at all times, but during a surge additional components get activated.

The inference I made, and you are right to ask me about it, was that since surge suppression needs that low pass filter to work, and that other specs are nearly identical to similar series mode surge suppression, then the filter knee should be about the same place.

From similar devices which have been measured that point is about 3 kHz.

Sorry to have stated such an assertion without actual hands on data.

Best,

E
Post removed 
erik_squires OP
16,180 posts
 
Here are the specs, from another piece of gear that uses SMP (Series Mode Protection) and LiFT( Linear Filtering):

  • Filtration Rating

  • 10 dB @ 10 kHz
    40 dB @ 100 kHz
    50 dB @ 500 kHz

    • This is not the same device, but the same features. The 10 dB @ 10kHz corresponds, roughly to working down to 3 kHz. Still, either measurement is a lot better than the typical EMI/RFI suppression which usually don't work until 100 kHz
    erik_squires OP
    16,180 posts
     
    @heaudio123

    I believe (back from my days working in this) that's there are limits to the amount of capacitance you legally can add across the H and N lines, no? Putting a coil in series helps with that. :)


    Post removed 
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