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Mains Filtration & EMI/RFI question

Discussion in 'Cables & Switches' started by dynamic turtle, Aug 11, 2004.

  1. dynamic turtle

    dynamic turtle
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    Hi,

    Before I go ahead and spend £££ on upgrading my mains supply (as seems to be the latest fashion in Hi-Fi), I need to ask a few questions. I hope the answers will prove useful to other forumers:

    1)Will a standard IEC cable suffer further airbourne RFI/EMI after it has left the conditioner, or will I have to invest in screened/filtered IEC cabling from the conditioner to the equipment in order to preserve the purity of the filtered electricity?

    2) Do I have to use screened IEC's for connection from the mains to the mains conditioner? (assuming the unit is supplied without a mains cable!)

    3) True or False, mains conditioners stiffle the dynamic range of your equipment, especially when connected to amplification equipment? Are they for sources only (transport-dac-pre)?

    4) Can I daisy-chain conditioners for improved performance?

    Thanks,
    DT
     
  2. alexs2

    alexs2
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    This is always a topic that produces a whole load of replies.....before going further,it's worth doing a search on this in the forums.

    A lot of the potential results of what you're proposing will depend on the quality of your mains supply as it stands,and if you have a good enough quality system to make it worthwhile.
    Assuming the answer is that you have a poor mains supply( as we have where I live,with overhead cables and frequent "brown-outs" etc),then begin by ensuring the wiring is up to standard,and ideally use a separate consumer unit,and either a dedicated ring main for the AV,or at worst,a spur.

    There are plenty of dealers etc who will sell you some very expensive mains cabling both for the ring main,and for the leads subsequent to that,but once you have a decent supply,then the benefits of expensive mains leads tend to diminish.

    There have certainly been plenty of reports of some mains conditioners(mostly those using capacitive networks etc to reduce HF noise)reducing the dynamic range of usually high powered Class A amps,which have an inherent high current draw from the mains....I don't use anything other than good quality (either Kimber or Transparent) mains cables for my rather old Krells.

    I've always compared the leads my gear comes with,to the likes of Kimber,XLO etc,and if I can't find any improvement,then I don't upgrade the cables....I do think that things like the Isotek conditioners are very useful for source components,and in the upper price range,things like the PS Audio and Accuphase regenerative supplies have a superb reputation for quality and noise rejection.

    Don't daisy-chain conditioners....you're more likely to add the delterious effects than gain anything.

    You may find the following link useful for some products and advice

    http://www.britishaudio.co.uk/pureseries.htm

    HiFI News also ran a very useful series of articles a couple of yrs ago on this,which would be very useful at least to read.
     
  3. dynamic turtle

    dynamic turtle
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    Thanks Alexs2,

    Can always rely on you for a speedy response.

    Firstly, I'm a tenant, so re-wiring the entire domestic mains is not possible. I don't think the landlord would find it a very reasonable request:

    "I reject the increase in rent due to the excess electromagnetic interference present in the mains electricity supply......"

    The house is a cardboard design by Barratt and is fairly new, so the electricity might be fine anyway (subwoofer resonance is a nightmare though :( ).

    I'll check out that website in the meantime.

    thanks,
    DT
     
  4. alexs2

    alexs2
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    LOL...I do appreciate what you're up against there....since you can't add a mains spur or similar,concentrate on mains conditioning.....leads can be very effective,but may end up being a moderately expensive method,when compared to the outlay on a conditioner such as the Isotek or Isol-8 products,depending on how much you want to spend.
    Also begin with the source components,as you're more lilely to get a noticeable result at a reasonable cost.
    You may also want to take a look around Russ Andrews website,not just for a few mains leads etc,but also things like the noise detector he rents out to assess your mains in the first place...he also offers a 60 day trial on his products which may be very helpful as well.

    Obviously,be aware that some of the leads fall into the excessively expensive class,along with some of the Nordost leads elsewhere,before someone else pitches in with examples of ridiculously priced products in this thread.

    Subwoofer room matching is another area altogether,and one reason why I've stuck with a relatively small REL in a very old timber framed house...I previously had a triamped active Krell/Linn Keltik system which when set up properly would run flat to about 20Hz,but was impossible to match to the house when we moved....so it moved elsewhere,and someone else is enjoying the Keltiks now.

    www.russandrews.com
     
  5. eviljohn2

    eviljohn2
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    Don't forget that making up mains cables yourself is a very viable option. Certainly a good way to see if there's a difference. As long as you can cope with wiring a plug you shouldn't have any trouble.

    A decent mains lead (made myself, Sid's Posh Power Cord design) did lower the noise floor on my sub.
     
  6. Shockabuku

    Shockabuku
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    That sounds interesting. Any tips on which cable/components etc to use in diy mains cables?
     
  7. eviljohn2

    eviljohn2
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    Going a bit off topic here but I made one of these:
    http://imageevent.com/sidandcoke/sidsposhpowercord

    There's a big sticky on DIY mains leads at the top of this forum which is quite interesting. Also look at things like the Supra Lo-rad which is more expensive.

    Basically, get a couple of decent plugs and put some better wire between them than you'd usually get from the supplied ones. At the very worst it'll look nicer :)

    If you need an extension block, I've had excellent results from some of the Belkin Surgemaster models. Mine has 75dB of RFI attenuation and generally makes a big improvement in all respects, particularly between interference of items connected to the block (my bedside light used to cause havoc!)
     
  8. Shockabuku

    Shockabuku
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    Nice one, thanks, I'll do some reading. Sorry for the hijak!
     
  9. ukaudiophile

    ukaudiophile
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    Hi,

    As a convert to the cause of mains filtration, I'll take a stab at these:-


    YES!! To a surprising degree. Don't get me wrong, it will still be MUCH better than not using a mains conditioner, but to me you lose about 20% - 30% of the conditioners advatage by not using fully screened leads. You don't have to go mad. I use the Isotek Elite leads, but before that I used the Premiums which are about £65 for 1.5M and the difference they made over the standard wet string was scary, I really felt I was being cheated by not having a lead of this basic quality supplied as standard. Bass firmed up, soundstaging, both size and focus, improved, the noise floor headed for the foundations and treble lost a bit of edge and bite which actually allowed me to hear more detail without undue HF emphasis.

    It would certainly help, but be careful here. To the best of my knowledge only FURUTECH cvonnectors are truly screened due to their design. Don't get too hung up on this, compared with the aerial which unscreened mains cables present, this is a relatively minor thing, but it is still worth examining.


    True......and False! Sorry to be vague, but it's all a matter of scaling. Most good mains filters will give you a rating for the power they can actually handle (beware any cheap units which don't do this). Now halve this and look at the maximum power your amplification can pull from the mains. If the pwoer drain of your amp is under 50% of the rated output of the conditioner, you're safe. The bad news is that power delivery rises in proportion with price, so this does make mains filtration for power amps and big A/V receivers costly, but ironically I've found these are the components which benefit most from it, not because they are more intolerant of noisy or dirty mains (though if you think about, as they're pulling more power than anything else in your system, they're taking in more noise and dirt, so it will do them the most harm) but also they throw out more rubbish onto the mains than anything else. This is a point which most companies, apart from Isotek and Isol-8 seem to overlook, that you not only need to protect your components from noise coming in, but also from them polluting each other's mains supply and to prevent noise getting out of a component. If a companies products don't mention this or give you a description for a strategy to deal with this, beware, they may not have thought of it, giving you another vulnerability.

    Here I will respectfully disagree with Alexs2, it has been my experience that you can get improvements doing this, but do not take it for granted that you will. I use both an Isotek Substation and a 2K Qube. I found that by cascading my substation off one of the outputs of the Qube I could get an improvement in my systems sound, but this is definitely a try before you buy exercise, as a friend of mine also with a 2K Qube and a Mini Sub reported a degradation in his system.

    I hope this has gone some way to helping you.

    Best wishes,

    Dave
     
  10. dynamic turtle

    dynamic turtle
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    Dave,

    Thanks for the very comprehensive response. I have since experimented with a basic filter and screened cable. I tried the filter seperately on my transport, dac and subwoofer. The most notable improvement came from the subwoofer where it magically gained 5dB's over the other channels when connected!

    I am going to build my own wattgate-enabled cable soon and will get back to you with the results.

    Cheers,
    Alex
     

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