Have your say & ask the experts

I have one on my set up and if nothing else it means my system is isolted from any mains blips or spikes and I can carry on watching a film in the middle of a black out.

Could this be worth a test?

 Let me know what you think.

 http://www.aeceuro.co.uk/t3_series.asp

[quote user="oldphrt"][quote user="bloney"]I've speculated on the effect of EMI and the ability of a PSU to reject it a few times, Oldphrt.  Not saying it makes a difference or not - I don't know and not tried - but this is one area where a shielded/filtered cable might concievably make a difference. [/quote] Aye, so you did. What type of EMI do you mean? Coming from where and from what? How would it get into the electronics of an amp via the mains without being totally obliterated by all the previously mentioned capacitors, the mains transformer and those big electrolytics?[/quote]

Well conducted EMI down the mains as well radiated EMI picked up on the cable (and through the vents in the casework, but thats another kettle..!)...  Erm, coming fom other electronic and electrical equipment, of course!  The laptop I'm using now will probably be particularly badf in therms of emc.  As I said a power supply won't 'totally obliterate' all the noise and rubbish, it only has finite capabilities.  To be EMC compliant with regards to susceptability it only has to not fail too disasterously - it doesn't have to be utterly immune to it or have it's performance completely unaffected by it.

I'm not saying EMI WILL be a problem - it might well be small enough to not be a problem - I don't know - it's just a thought.  But I do know it won't be completely obliterated though. 

It seems to me that mains conditioners and filtered mains leads are a not at all cost effective cure for a problem that doesn't seem to actually exist. If it did, winding the mains lead round ferrite rings would work just as well and be a lot cheaper.

There's no defence at all for outrageously priced mains leads though. A kettle lead is perfect as a replacement on an amp. Lovely thick cable.

A ferrite ring is a bit of a sticky plater cure for emc - it'll only help a handful of dB, while a properly designed filter will offer an order of magnitude more protection.  From memory figures like <10dB compared to 90+dB.  So there is something to be said for properly designed filtered.  But as you say - they might be already designed in.  But as others have suggested they might not be on budget kit.

Or, as you say - it might not be a problem at all!

Yeah - I can't see the justification for the silly money cables.  I saw one for over three grand on the web the other week!!!  Funny that some things are amazingly cheap - I had a look inside a floppy disk drive once - the engineering is amazing and you can buy one for a tenner or so.  And cheap cars, dunno how it's done when all the markups are taken into account.  But some things - like esoteric audio stuff - is ridiculouslky prices - I guess mass production has a lot to do with it.  Then there's the thing about a bottle of wine not selling at £2 but will sell loads at £20.

I have tested mains spikes by placing a Gas surge arrestor across Live and Neutral after an RCD, these work by if the voltage raises above the value of the arrester the plasma gas inside conducts and creates a short from L-N squashing the spike.This of course trips the RCD. Fitting a 300V arrester gave some very worrying results, it constantly fired all day with lunch time being the worst 12pm to 1pm it fired 48 times. So thats 48 times the mains spiked over 300V, this is not very healthy for your equipment. A 600V arrester was tried the following day and it fired 7 times. These are very big short duration spikes. I then made my own passive filters using capacitors and transient diodes, this pulled the spikes down to below the 300V threshold on most cases and only fired the 300V gas arrester 3 times all day.

This may sound a bit techy to most people but I thought I would share my findings so people know what dirty mains we really have

Fitting filters removes a large chunk of the noise off the mains and squashes spikes down to a more acceptable level. Hi quality mains leads are usually low impeadance low loss copper/silver. The better ones are the Kimber cables that have a RF rejecting weave.

Filters fitted into equipment (even expensive items) is quite poor, mainly because the components needed to do a proper job are fairly large and of course cost.

Brent

I have tested mains spikes by placing a Gas surge arrestor across Live and Neutral after an RCD, these work by if the voltage raises above the value of the arrester the plasma gas inside conducts and creates a short from L-N squashing the spike.This of course trips the RCD. Fitting a 300V arrester gave some very worrying results, it constantly fired all day with lunch time being the worst 12pm to 1pm it fired 48 times. So thats 48 times the mains spiked over 300V, this is not very healthy for your equipment. A 600V arrester was tried the following day and it fired 7 times. These are very big short duration spikes. I then made my own passive filters using capacitors and transient diodes, this pulled the spikes down to below the 300V threshold on most cases and only fired the 300V gas arrester 3 times all day.

This may sound a bit techy to most people but I thought I would share my findings so people know what dirty mains we really have

Fitting filters removes a large chunk of the noise off the mains and squashes spikes down to a more acceptable level. Hi quality mains leads are usually low impeadance low loss copper/silver. The better ones are the Kimber cables that have a RF rejecting weave.

Filters fitted into equipment (even expensive items) is quite poor, mainly because the components needed to do a proper job are fairly large and of course cost.

Brent

Yes well designed equipment has better voltage rails inside compared to cheaper equipment but these circuits are still bombarded by the same noisy mains coming in.

Brent

[quote user="rowemeister"]No it does not!!!!! I'm an audio engineer and can quite catagorically say it does not. A vdr and an inductor does not constitute proper mains filtering. Infact inline inductors used by lots of manufacturers adds impeadence to the mains which reduces the dynamic effect of the music,also the vdrs they fit do wear out overtime and therefore no longer work.

Yes well designed equipment has better voltage rails inside compared to cheaper equipment but these circuits are still bombarded by the same noisy mains coming in.

Brent

[/quote]

If the mains was as bad as you say it is none of us would be able to use light dimmers and all the cheap stuff would be crackling and popping continuously or blowing up. It's hyperbole.

Transformers in cd players amps etc absorb these spikes but it creates a saturation effect where the transformer shuts of momentarily causing a pulsed secondary output. The noise on the sinewave of mains is transfered through to the secondaryand psu.

A dimmer is a variable resistor and small surges on overvoltage do not effect these, lots and lots of spikes do however shorten the life of a bulb. If you run just about any light bulb at 90% it will last approx 100% longer.

Noise on mains effects things where conversion is required, digital electronics is very delicate. Look at a good pc power supply or a server psu. It is full of mains spike protection so that these spikes do not interupt the cpu etc.

Remember we are talking about the effect noise and spikes have on audio

Brent

Don't bother!  This old chap is continually asking for objective evidence and measurements and proof.  The fact that you've actually tried to give him some is highly unlikely to actually have any influence whatsoever on his opinion.

Mind, it has to be said, I still reckon (without listening evidence I hasten to add) that a simple piece of wire, no matter what it's made of, even miraculem or unobtainium or whatever, isn't going to affect the sound UNLESS there are also some intentional filtering properties in there.  If for no reason beyond the "thought experiment" of moving the system a socket closer to the distribution board instead since 100m of copper plus 1m of pure silver is still a poorer conductor that 95m of copper.

Are you say that the weave of the cable can produce such filtering results (and I don't mean shielding or noise rejection as per a twisted pair)?

A cable or main-block that actively filters the mains to remove spikes and noise does seem plausible to me, certainly given your results.

If the mains was as bad as you say it is none of us would be able to use light dimmers and all the cheap stuff would be crackling and popping continuously or blowing up. It's hyperbole.

[/quote]

Why on earth do you bother coming back repeatedly? 

[quote user="Andrew Everard"]

Why on earth do you bother coming back repeatedly? 

[/quote] 

Because he like's a lively debate with lots of neutral participants..