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Main filters. Are they worth the wedge?

Discussion in 'Hi-Fi Stereo Systems & Separates' started by markyd101, Apr 15, 2005.

  1. markyd101

    markyd101
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    Firstly hello. My first posting so here goes.
    I have been browsing on Ebay and have again come across what seems to me overpriced mains filters. Are they worth spending a ridiculous amount of money on. I am running Arcam A80 and P80 amps to rogers LS55's. QED silver anniversary cable, Van Der Hull and chorus interconnects and wonder if I will notice a huge difference with a filter. I am electronics trained and could build one if someone had the diagram and prefered component values and tolerances. Or does anyone know anybody who builds them as a hobby for a reasonable price. All input will be appreciated.
    Thanks :thumbsup:
     
  2. Londondecca

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  3. peterlowe

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    I was very sceptical as to whether a mains filter cable would really have much effect like yourself. I know you can spend 1000 pounds plus on these cables, that just seemed really stupid to me - "whats the world coming to" I thought. I settled for What Hifi magazines product of the year, the Russ Andrews Classic Powerkord for 75 quid. I was very pleasantly suprised because as promised in reviews, my musical Rotel experience was given a welcome boost - especially in the midrange. Vocals sounded much more solid, with greater presence and focus, while instruments were treated with an extra coat of realism. How much difference cables with increasing cost i dont know, but I now know they have the ability make a relatively significant difference in sound :smashin:

    - Pete
     
  4. SKA.face

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    Why not try a seperate spur at first?This is what I did,maybe a cheaper first port of call.
     
  5. cosmicma

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    this thread is about as old as the other i just posted in ( didn't realise :) )

    well all i have to say on the matter is
    is your amplifier based on a switch mode power supply ??? if the answer is yes then there's a chance you will hear a difference
    is your amplifier based on a transformer based power supply ??? if the answer is yes then the difference will be didly squat and ive yet to come accross something that will change my mind on that
     
  6. Knightshade

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    Hi Cosmicma,
    Are you sure you haven't got that the wrong way around?
     
  7. deanym

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    This thread could deteriorate rapidly if past experience is anything to go by!!! The belkin pure av power isolator is well made. has marginal filtration and works quite well.

    Ebay has a few home made jobbies and the testimonies compare them favourably against the isotek stuff.

    I've bought a couple off ebay form a certain guy and they work quite well, plasma picture loses some grain and power amps for cd system give cleabner sound. However on my cd player with a high quality mains lead, there's very little differece.
     
  8. Paul Williams

    Paul Williams
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    In the past I've used and discarded many filters as, although they have improved some elements of the sound, all have clouded vital aspects of transparency. I know that some people relate the treble detail or sparkle to an feature of distortion or grain (not really the right words) present in the higher registers and when this is removed the sound is more lifeless - well so be it, I'll keep this and pass on the filtered sound. The most successful filter I've encountered was the "Power" produced by dpa, which I used until a few weeks ago, but sold, as this could no longer cope with the periods of high mains noise. I plugged it in when things got bad and removed it during late night listening sessions.

    So I’m now also looking for a solution to ridding my system of mains borne contamination. The only real solution I feel is mains regeneration AC to DC and back to AC, but I can’t stump up the cash for a PS Audio unit – but if I had the cash, that’s what I’d get.

    I have talked to several manufacturers/retailers and many guarantee “…..will not reduce transparency…..will leave high level detail intact..” or state it will improve these elements by the removal of noise from the mains supply. So this would seem to be the main level of criticism against these units. Ben Duncan’s stuff through the Moth Group is declared to be a filter free zone, but I’ve heard very varied responses. The real question is how many of these products are offered with a money back guarantee if not satisfied? Well I’m going to try one of the Missing Link “Opus” power cables with an inline filter, as this is offered on a “try before you buy deal”. At the same time I’ve purchased a couple of metres of their lowest cost screened cable and will make up a basic (screened) lead for myself to try as a base level solution.

    As for a separate spur this will help but not remove the problem if it’s bad. In my case I have the whole of my listening/HC room on a separate consumer unit. This feeds one ring main in the room and 5 spurs or radial lines direct from the consumer unit. All the digital/HC stuff is relegated to the ring and the Hi-Fi uses the individual spurs (don’t consider CD as Hi-Fi yet). One things for sure, mains borne contamination is set to increase and there will be a growth of solutions – but I still feel that regeneration is the way to go, but until the cost become more reasonable I’m not going to really find out.

    Paul
     
  9. cosmicma

    cosmicma
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    nope
    switchmode supplies are totaly reliant on there input because the mains is directly manipulated to achieve the desired voltage where on the other hand a transformer based supply is not so fussy because mains is isolated and then rectified , smoothed etc.. ( maybe not the best explenation but you should get my point )
    but nothing will make up for bad house wireing be it transformer or switchmode
     
  10. Knightshade

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    Strange, I've always found the opposite. Transformer (such as Toroidal) based supplies. (Depending on the quality of the windings, isolation, shielding etc) AC rectifed to DC, smoothed, filtered, regulated and depending on how good the Caps and circuitry are you may or may not get a smooth sine. I don't really see how this can be affected by mains supply but for some reason (In my experience) it is..... Unless they are of very high quality.
    I have always found switchmode power supplies to be very dependent on quality components (Ultra fast recovery diodes etc). A bad switch mode supply is rubbish. Filtering the mains here may help slightly at least providing a steady voltage so the unit lasts more than a year! But as for improving the sound quality? Sorry doesn't happen. Any good switch mode supply will filter the mains and offer large amounts of clean power very quickly. Changing the mains input to a 'good' SMPS will make little or no difference if the designers have done there job properly.
    Saying that they are more difficult to build than a standard supply. Perhaps that's why so many manufacturers get them wrong?;)
    Think I'd address the problem at source rather than play with filters....
     
  11. movie_fan

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    Hi, regarding this topic, does anyone know the Solitaer Audio mains filters?
     
  12. CambshireGordon

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    On the topic of mains borne interferrence and mains filters - a bit of lateral thinking on my part.
    Has anyone tried a portable generator - you know, the type often seen in use by market stall holders to power their lights and (infernal) radios? Or what about a wind generator used by the boating fraternity? Or is the AC produced by these types of generators full of other sorts of nasties? CambshireGordon.
     
  13. Antpink

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    Now here's a good idea - a small wind or solar powered battery bank - like an industrial type UPS on a constant trickle charge.... In theory, you could junk all the AC componentry and feed direct DC which could be regulated to the correct voltage using high performance regulators. Might be a tad expensive to implement and you'd be cursing those cloudy and/or still days when they happen.... :D
     
  14. CambshireGordon

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    Not a problem for me - One (only?) good reason for living on the edge of the Fens!
     
  15. severnsource

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    Generators - unless you pay lots of money or go to extraordinary lengths to acoustically isolate it, the noise pollution from the genny will grossly outweigh any theoretical improvement in mains quality. The frequency stability and load regulation of cheap generators doesn't tend to be very good, even if the quality of the sine wave is OK.

    Most wind generators or solar panels need an inverter to produce mains voltages. The more affordable ones don't produce a sine wave, most of them give a modified square wave which will have lots of 50Hz harmonics, which won't be good for sound quality if your equipment is sufficiently badly designed to need a very clean mains supply.

    Bill
     
  16. alexs2

    alexs2
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    Once again,the topic of power cords and supplies rears its ugly head!

    If you do a search in the cables section of the forums,you'll find a wealth of rancour and controversy on the topic....all I'd say is that in certain circumstances(i.e dirty mains supplies etc),then spending money on good quality leads can be very worthwhile,but as pointed out above,attending to the supply inside the house by adding a separate high quality spur can reap far greater benefits.

    The value of cables with respect to the type of power supply(i.e SMPS Vs transformer/rectifier)often has very little to do with the type of supply....in my own experience,some items benefit,and others dont....I've used some pretty expensive cables with my Krells(massive 2Kw transformers and coke can sized caps),before reverting to the original screened 30A cables they came with,and had very good results with other gear,both SMPS and Tx based....entirely down to the individual equipment.

    Portable generators unless of very good quality(read expensive) often produce mains of variable voltage and frequency,and wouldnt get a place in my house other than for emergency use.

    If you really wanted the ultimate mains quality(and many swear by them for source or low power items)then a regenerative supply as made by Accuphase or PS Audio represent the best,but at a very high price.
     
  17. Paul Williams

    Paul Williams
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    As per my earlier post I'm now looking toward screened mains cable to use with the units and based on initial results from the 2 leads made up on Friday, these are have a reasonable effect on the sound. But this points toward contamination arising either from equipment close by (and their associated interconnects) or the equipment I'm using the screened leads for.

    Also mentioned in my earlier post the Listening/Home Cinema room has its own consumer unit with individual spurs for the Hi-Fi and mains voltage is very consistent. But the screened leads are an improvement, not only reducing the grainy sound but adding detail and providing a wider soundstage – not bad for £4.50/metre + £1.75 for an IEC plug, £0.65 for the mains plug and some DIY. Now I’m going through each individual bit of kit & so far both the pre-amp (tube/tube rectified) and the Phono stage (SS) respond well to the screened leads. I may look to upgrading the plug on either end of the cables to silver plated items (maybe even the wall sockets). Incidentally, when I quized someone about the efficacy of using silver as it tends to corrode/blacken with exposure, I was told this build-up on the surface is far more conductive than copper – any one out there care to comment?

    Paul
     
  18. alexs2

    alexs2
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    That black or corroded surface will consist of oxidised silver,which certainly isnt more conductive than unoxidised copper.

    The real point is though that the ends of any decent cable should be terminated with an equally decent set of connectors(spades,bananas etc)to allow a good,tarnish-free connection to be made with the speaker and amp,which will not deteriorate over time.
     
  19. Paul Williams

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    Anyone have any experience of Constant Voltage Transformers (CVT’s) or Medical Isolation Transformers (MIT’s) as these would seem to offer the solution to bad mains. They are certainly very common in emerging countries with power supply issues. The main disadvantage(s) of the CVT, as far as I can see is the fact that they tend to ‘hum’, therefore would require remote placement, and are very heavy 55kg for a 2000w unit (only! 22kg for a 650w unit though). MIT’s would appear to be silent, but don’t provide the pure sine wave output, can’t compensate for low voltage and harmonic noise.

    Paul
     
  20. DAMOON

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    The cheapest and best upgrade you will ever make

    I have tried and demonstarted this product on the best well £15000 worth anyway, nearly actually sold them myself but never had the funds to start up the business. Once heard never forgoten or removed.


    Buy from RS components looks crap but does the buisness

    AVR 02-22ER £162 plus vat
    or larger if you are running a large system

    Feed the whole system from 1

    Also
    Thurlby thandar they make a Mains synthizer for use with highly accurate mearuring equipment £500 fan inside so have to be put out of room
    Try
     
  21. Ron Williams

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    Hello Everybody,


    The idea of "screened mains leads" if installed correctly, will prevent RF entering the supply lead to your equipment, BUT!


    Do you have, or ever used an indoor television or stereo aerial? If the answer is yes, then you will prove to yourself that walls do not prevent RF.


    With this in mind, even, if like me, you have installed a separate consumer unit to feed for your HiFi and Vision equipment, you will still get RF entering the supply to your equipment between the consumer unit and the wall socket your expensive "screened lead" is plugged into.
    So, how far back along the supply line to your equipment do you screen???

    Kind regards,

    Ron.
     
  22. formbypc

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    As far as you can.
     
  23. BlueWizard

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    Perhaps I'm misunderstanding the flow of the conversation. But you want to add power line filters as close to your equipment as you can.

    Also a screened cable means a shielded cable, but the power line is massively greater than the inducted RF signal that might appear on the power lines. It is the same reason why speakers wires are generally not shielded. Any RF noise the speakers might pick up is tiny compared to the actual signal.

    Plus, all power supplies have basic RF filtering in them usually in the form of a tiny capacitor across the large power supply capacitors. This short RF right at the DC supply. Everything beyond the DC Supply is inside a shielded case.

    Th main concern with the mains is that they are as direct as possible, with the fewest number of spliced and junction as possible, and the fewest number of noise generating devices plugged into the same circuit. You don't want you stereo on the same power line as motors and compressors.

    If any splices or junction in the power line are not tight and clean, then with each power surge, there could be a slight loss in voltage to the amp (as an example). But, internally you have a regulated power supply that can tolerate a drop in input voltage while still maintaining output DC voltage.

    The other aspect that some type of filtering surge suppression strip gives you is lightening strike surge protection. There are small devices that are a short to high voltage transients, but fully open to normal voltages.

    The only true line voltage regulation comes from a Ferro-resonant transformer, which can magically increase the voltage on the output, if the voltage on the input goes up or down.

    Just a few thoughts.

    Steve/bluewizard
     
  24. Ron Williams

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    Hello Formbypc,

    I think you have misunderstood the intermation behind my question.

    It was very much "tongue-in-cheek".

    The point I am trying to convey is, you can spend from just a few pounds to ridiculous amounts for a "screened lead" to connect the wall socket to your equipment and RF will not penetrate that length of lead if it is earthed but, the mains power cables from the consumer unit to the wall socket are still vunerable, this I know from first hand experience as one of my hobbies is Amateur Radio which involves high powered RF transmitters covering the radio spectrum from 1.5Mhz to 440Mhz.

    Use toroidal rings on speaker leads as close to the rear of the speakers as possible, the same applies for all "input" leads to the pre and power amps and all power leads, 240 and low voltage. In stubborn cases, you can use more than one toroid side by side. Happy listening.

    Kind regards,

    Ron.
     

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