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Surge protectors-why is it restricting sound?

Discussion in 'audio' started by Philim, Apr 15, 2013.

  1. Philim

    Philim pfm Member

    I am running a Naim XS off a surge protector and have noticed what I can only describe as a wave of sound quality - sometimes OK; sometimes muffled. Having seen a few threads saying "all Naim equipment must be run from a wall socket" I tried running straight from a £4 basic extension lead and the difference is quite noticeable. Linear performance, more detail and separation but a little brighter.

    WHY? WHY? WHY?

    On the flipside I might paint my £4 extension lead black and sell for £250 on the Naim forum.....
  2. sq225917

    sq225917 situation engineer

    because the surge protector increases the impedance of your mains supply and probably inject HF noise into the bargain, or you've imagined it.
  3. dave

    dave Plywood King


    An email to support@naimaudio.com will get you an accurate answer if not the same as Simon suggested with minimizing mains supply impedance (the prevailing theory.)

    FWIW, I run my Naim rig here without extension cords or mains blocks for the same reason - it sounds better that way.


  4. Mike Reed

    Mike Reed pfm Member

    Plus one, and that goes for filters or other impediments to supply.
  5. Alex S

    Alex S carbon based lifeform

    You are using the wrong fuse in it.
  6. thebiglebowski

    thebiglebowski pfm Member

    Naim recommend star earthing so things like the grahams hydra are a good option. I used one for my 202/200 hicap/napsc system and whilst i didn't notice much of a change i was able to power it all from a single wall socket.
  7. Mike-B

    Mike-B Self opinionated techie

    Surge protectors have a number of components that reputedly spoil SQ
    X & Y capacitors (IME) soften SQ
    Varistors (VDR or MOV) the avctual surge protector, although normally set to operate above the nominal voltage, they tend to rim the top end of te wave peak

    Finally what are do you think you are protecting against ???
    These devises will simply vaporize with the potential of a lightening strike - the only protection for lightening is a good insurance policy
    UK power is as good as anywhere on the planet & high voltage surges as found in 3rd world places that could damage equipment do not happen.
  8. adamdea

    adamdea You are not a sound quality evaluation device

    I'm sure you have strong feelings on this subject but there's no call for that kind of language.
    TheFlash likes this.
  9. Mike-B

    Mike-B Self opinionated techie

    Ooops sorry I must TRIM up my bad language

    DANOFDANGER pfm Member

    How can anything before the amplifier mains affect sound quality, the signal is regulated to dc and if the psu is done well enough it will compensate for whatever voltage droops/rises there may be.

    Please explain.
  11. sq225917

    sq225917 situation engineer

    Not all amps are built equal, PSRR varies with design, harmonics on the mains make their way through, DC on the mains causes the transformer core to saturate, lowering it's ability to do it's job.
  12. Mike-B

    Mike-B Self opinionated techie

    2 answers in my experience

    I hear what I hear & I have heard a so called surge protector that included VDR, X&Y caps & C&D mode chokes that softened the sound on my old Audiolab system a few years ago, then when I dug it out & used it with my Naim, it did the same.

    Years ago I managed a project to develop a prototype command vehicle that was required to have very low electrical noise.
    They had to run off both mains power & a number of different mobile generators. In an effort to suppress electrical noise from the generators we designed in stuff that included capacitors on the power input. It resulted in downstream issues with low voltage & 24vDC regulation. Problem was the waveform was distorted so it was no longer a pure sinusoidal form, the transformer current draw & its AC output was affected. We removed most all the capacitance & the problem was solved

    How that might transpose into the SQ of an amp, I am not sure & not claiming it does.
    Maybe some of our DIY builders can add something
  13. martin clark

    martin clark pinko bodger

    It's a big horrible mess. Bits added there interact with everything upstream and down, all the strays along the way (wiring and transformer leakage inductances and so forth) so its very difficult to make blanket recommendations. Or even recommendations at all other than leave well alone unless you're sure your power is so bad you need remedial measures.

    I've experimented quite a bit with filtering design. Take just one element -adding varying amounts of capacitance across the line at the input to amps*. It's quite easy to provoke more and peakier noise within the audio band measured at the AC power input to the amp than without. Again, this may or may not manifest itself as measurable (let alone audible) outcomes on the audio output, depending on the object powered.

    * Exactly as often sold as a 'parallel filter' or some such nonsense.
  14. Whaleblue

    Whaleblue Southbound

    That was sarcasm, right? ;)
  15. TLS

    TLS pfm Member

    Has someone tried large isolation transformers from Torus or Bryston? They provide a lower source impedance and don't seem to have caps.
  16. martin clark

    martin clark pinko bodger

    It's still higher impedance than the raw mains, plus a small amount of leakage inductance. (in the UK Airlink among others can also supply high quality units up to 'enormous' )

    I've got a largish (well, 1.5KVA continuous rated, about 20kG) isolation transformer and even so teh few times I've played with it on the system it gave a flattening effect on dynamics was noticable even with a load as weedy as a Nait2. Not sure why, nor much pursaded to investigate. I only use it when I need isolation i.e. on the bench.
  17. TLS

    TLS pfm Member

    Bryston's brochure says a standard wall receptable have a higher nominal impedance.
    BIT power isolation units present low impedance to any electronic
    device that is connected to them. A Single 20 amp BIT PIU has
    an output impedance of 0.2 ohms and can deliver 400 amp peaks
    (instantaneous current). The 100 amp unit only has .04 Ohms
    of output impedance. A typical 200 watt audio power amplifier
    demands 10 amps RMS current from a 120 volt line (1200VA)
    but may demand up to 50 amp instantaneous peaks. The standard
    residential wall receptacle can’t supply the 50 amp peaks because
    they typically have higher nominal impedance. A BIT 20 amp
    PIU plugged into the same wall plug can supply these peak current
    requirements quite easily

  18. sq225917

    sq225917 situation engineer

    Last time I checked impedance was cumulative...
  19. martin clark

    martin clark pinko bodger

    Looks like its using the Plitron narrow-bandwidth transformer.

    But still, that press release makes no sense. That energy has to come from the wall socket, and it's not a step-down transformer. The transformer itself may have a lower wire resistance than the mains that feeds it but that alone does nothing.
  20. mark121211

    mark121211 pfm Member

    Most of the RFI filters I have seen use a couple of Y caps connected from Live and Neutral to earth. These filters are no good for audio use.

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