RF & EMI

[Chris53]

I'm still plagued by one or perhaps both of these two annoyances. My system sounds smoother at around 4am after my next door neighbours have switched off their TV/wi fi equipment.

I've tried all sorts of ferrite stuff on the mains cables and the interconnects. I have a belkin pf30 in use. I have QED shielded mains cables. None of these eliminate the problem.

My "guess" is that its not RF as I would hope that all of the above would be getting rid of that, but maybe I'm wrong. I wonder if its more likley to be EMI causing the harshness that I get. I have tried several different interconnects from van den hul to chord and others. They all sound different but don't solve the problem. I've read that Kimber cables are good at reducing the effects of EMI but some of their cables are way out of my price range. I wonder if their cheapest would help?

Does anyone have any experience of this? Miracle Wraps have helped improve the sound but they don't solve this problem.

[Deleted]

Chris
I have seen reports that mains filters sometimes make matters worse.
Alex

www.acoustica.org.uk/other/filter.html

[XTRProf]

RF shouldn't affect too much from wifi as your hifi is metal box and earthed. Also, wifi is low power RF and not something like living under a broadcast antenna. Alex can tell you more on this as he worked in the Telecoms for a long long time before retirement.

For RFI and EMI thru our mains, the usual ferrite and mains conditioner will have taken most of the problem away without much restriction to dynamics if the parts used in them are high current enough. If everything failed and also for the ultimate, go for one of those high wattage AC mains regenerator like the Power Plant from PS Audio. Those high power ones from PS Audio is nowadays even enough to take on a high watter power amp without too much restriction in the dynamics. But that is in technical specs only as usual and you need to try one out in your system to see whether it does have any disastrous effects on your system. Always KISS wins.

[Deleted]

Consider that the problem is NOT the equipment, mains nor the neighbours.

It seems you have done the part on filtering already and as long as you don't have a wifi or other wireless transmitter (DECT phone) within 30cm of your equipment it is highly unlikely the cause.
This has to do with field strenghts and operating frequencies, grounding, wiring and immunity.
I severely doubt the 'problem' is electric, but most likely of 'the other kind'.

In my limited 30 years of experience and experiments I have always noticed in the wee hours listing is 'better'.
Several reasons are deposited for this phenomenon.

1:Human spiecies from the early days they walked on the earth had to rely on hearing at night so at night this is 'enhanced'.
2:Because in the wee hours the lighting is less and the ears (slowly) become more dominant.
3:The brain is more relaxed and can focus better on sounds.

For serious listening the late evenings are simply best for everyone.
The common belief that this is (or must be) caused by 'garbage' on the mains is only good for sellers of remedies (mains filters, shielded or special cables, Peter W Belt, UPS, regenerators)
Remember the biggest garbage on the mains is caused by badly filtered equipment in close proximity (electrically) to the equipment.
several meters of cable already presents a high impedance for RFI.

But this is just my opinion of course and could be totally wrong on this.

[Chris53]

Jan 25, 2012 8:51:35 GMT @sandyk said:

Chris
I have seen reports that mains filters sometimes make matters worse.
Alex

www.acoustica.org.uk/other/filter.html

I must give that a read. Filtering may well be making my system sound worse I guess. However as any filters are in use all the time it doesn't explain the difference between other times and the 4am sound.

[Chris53]

Jan 25, 2012 10:11:53 GMT XTRProf said:

RF shouldn't affect too much from wifi as your hifi is metal box and earthed. Also, wifi is low power RF and not something like living under a broadcast antenna. Alex can tell you more on this as he worked in the Telecoms for a long long time before retirement.

For RFI and EMI thru our mains, the usual ferrite and mains conditioner will have taken most of the problem away without much restriction to dynamics if the parts used in them are high current enough. If everything failed and also for the ultimate, go for one of those high wattage AC mains regenerator like the Power Plant from PS Audio. Those high power ones from PS Audio is nowadays even enough to take on a high watter power amp without too much restriction in the dynamics. But that is in technical specs only as usual and you need to try one out in your system to see whether it does have any disastrous effects on your system. Always KISS wins.

Thanks that's interesting. I used to use an Airlink balanced mains transformer which did affect the sound but it didn't seem to solve this problem I have. I imagine the PS Audio regenerator won't be cheap. I'll take a look.

[Chris53]

Jan 25, 2012 12:28:08 GMT @solderdude said:

Consider that the problem is NOT the equipment, mains nor the neighbours.

It seems you have done the part on filtering already and as long as you don't have a wifi or other wireless transmitter (DECT phone) within 30cm of your equipment it is highly unlikely the cause.
This has to do with field strenghts and operating frequencies, grounding, wiring and immunity.
I severely doubt the 'problem' is electric, but most likely of 'the other kind'.

In my limited 30 years of experience and experiments I have always noticed in the wee hours listing is 'better'.
Several reasons are deposited for this phenomenon.

1:Human spiecies from the early days they walked on the earth had to rely on hearing at night so at night this is 'enhanced'.
2:Because in the wee hours the lighting is less and the ears (slowly) become more dominant.
3:The brain is more relaxed and can focus better on sounds.

For serious listening the late evenings are simply best for everyone.
The common belief that this is (or must be) caused by 'garbage' on the mains is only good for sellers of remedies (mains filters, shielded or special cables, Peter W Belt, UPS, regenerators)
Remember the biggest garbage on the mains is caused by badly filtered equipment in close proximity (electrically) to the equipment.
several meters of cable already presents a high impedance for RFI.

But this is just my opinion of course and could be totally wrong on this.

I have thought that it could all be down to my perception but I am convinced there IS a problem. My neighbours are often up late until 2 or 3am. I am sometimes up late myself and the sound can be edgy at 3am but better at 4am. It seems to coincide with them switching off the TV and/or whatever else they may be using until that time. I know their TV is right the other side of the wall to where my hifi is so I wonder if something is radiating enough to cause a problem, (I can't move the hifi about due to marriage!). This why I was wondering about the Kimber cable because it is "supposed" to be better at EMI shileding due to its construction. It's too expensive to just buy in the hope it will improve the sound so I am a bit stuck... and I may be barking up the wrong tree anyway of course.

[Deleted]

I would simply ask the neighbour kindly if he is willing to participate in an experiment and have him shut down his stuff for 5 mins while you listen.

Another test would be to move your setup for one evening, The wife probably doesn't mind if all reverts back the same evening and you would have gained knowledge.

These are simple things that don't cost anything and provide valuable info.

From my professional experience (EMC/RFI) point of view:
In order to compromise equipment they would have to emit a LOT of RF power.
Most appliances have to comply to rules, if they do they should not interfere nor should your gear.
Open frame thingies, badly shielded gear (DIY or shop bought) might be an exception.

[XTRProf]

Jan 25, 2012 17:31:33 GMT Chris53 said:

Thanks that's interesting. I used to use an Airlink balanced mains transformer which did affect the sound but it didn't seem to solve this problem I have. I imagine the PS Audio regenerator won't be cheap. I'll take a look.

As for the regenerator, there are various wattage sizes. So pick one up that can solve your problem for your current application. But better you can on T loan first to see what the effect is. I think that can be arranged when you put a deposit first and get back your deposit when you are not fully satisfied with the results. So go to a nearby friendly Hifi shop and start networking.

My friend also have a DIY balanced transformer of 2KVA. Yup, you are not seeing things. 2KVA for just his tube SET 300B. He kept boasting about how queit and better sounding his system was with it when those invited heard the opposite. The sound was shrill, dynamics compressed and the singer seemed to have a cold when singing. One of us requested he removed the balanced traffo to see what the effect was. The transformation was night and day for the better. He has since sold that traffo to another poor soul who only believed in technical specs. So the moral behind don't need to say more right?

But since you had tried a balanced traffo and it didn't have the desired effect as you wanted, it's probably not something from RFI and EMI in the mains as the balanced part would have cancelled out the RFI and EMI. Have you tried a balanced IC if you have XLRs in your equipment to see the effect? If that also didn't cure, it's probably is not RFI and EMI related as signal and power already covered. The RFI and EMI thru air, as Frans had said, is just very small amount as the equipment must meet stringent radiation specs before they can be imported or exported in the EU and US of A for newer products.

[Chris53]

Jan 26, 2012 5:35:15 GMT XTRProf said:

Jan 25, 2012 17:31:33 GMT Chris53 said:

Thanks that's interesting. I used to use an Airlink balanced mains transformer which did affect the sound but it didn't seem to solve this problem I have. I imagine the PS Audio regenerator won't be cheap. I'll take a look.

As for the regenerator, there are various wattage sizes. So pick one up that can solve your problem for your current application. But better you can on T loan first to see what the effect is. I think that can be arranged when you put a deposit first and get back your deposit when you are not fully satisfied with the results. So go to a nearby friendly Hifi shop and start networking.

My friend also have a DIY balanced transformer of 2KVA. Yup, you are not seeing things. 2KVA for just his tube SET 300B. He kept boasting about how queit and better sounding his system was with it when those invited heard the opposite. The sound was shrill, dynamics compressed and the singer seemed to have a cold when singing. One of us requested he removed the balanced traffo to see what the effect was. The transformation was night and day for the better. He has since sold that traffo to another poor soul who only believed in technical specs. So the moral behind don't need to say more right?

But since you had tried a balanced traffo and it didn't have the desired effect as you wanted, it's probably not something from RFI and EMI in the mains as the balanced part would have cancelled out the RFI and EMI. Have you tried a balanced IC if you have XLRs in your equipment to see the effect? If that also didn't cure, it's probably is not RFI and EMI related as signal and power already covered. The RFI and EMI thru air, as Frans had said, is just very small amount as the equipment must meet stringent radiation specs before they can be imported or exported in the EU and US of A for newer products.

Thanks for all this. I think the regenerator is going to be outside my budget at the moment and I would certainly want to make sure it made a difference before spending that kind of money so the idea of having one on trial would be an absolute must.

It's intersting to hear you say that a balanced supply should have sorted out the problem. It suggests that, as you say it's not mains borne interference. I don't have XLR's so I can't try your balanced interconnect idea. I am wondering though if it is the the interconnect that is picking up the interference. This is what led me to ask about the Kimber cables which claim to be particularly good at reducing the effect of EMI. I still wonder whether they would do the trick but again I don't really want ANOTHER interconnect unless it will solve this problem.

[Chris53]

Jan 25, 2012 20:38:36 GMT @solderdude said:

I would simply ask the neighbour kindly if he is willing to participate in an experiment and have him shut down his stuff for 5 mins while you listen.

Another test would be to move your setup for one evening, The wife probably doesn't mind if all reverts back the same evening and you would have gained knowledge.

These are simple things that don't cost anything and provide valuable info.

From my professional experience (EMC/RFI) point of view:
In order to compromise equipment they would have to emit a LOT of RF power.
Most appliances have to comply to rules, if they do they should not interfere nor should your gear.
Open frame thingies, badly shielded gear (DIY or shop bought) might be an exception.

Thanks for your suggestions, I may try the move equipment option as I don't think I get on well enough with my neighbour to ask him to help.

[XTRProf]

Jan 26, 2012 20:32:30 GMT Chris53 said:

This is what led me to ask about the Kimber cables which claim to be particularly good at reducing the effect of EMI. I still wonder whether they would do the trick but again I don't really want ANOTHER interconnect unless it will solve this problem.

As I had said, get a loan from a friendly hifi shop. Shouldn't be too much of a problem. So start networking with these shops and before long you will have the IC in your system.

I think you know the drill.

[nicoboom]

My friend also have a DIY balanced transformer of 2KVA. Yup, you are not seeing things. 2KVA for just his tube SET 300B. He kept boasting about how queit and better sounding his system was with it when those invited heard the opposite. The sound was shrill, dynamics compressed and the singer seemed to have a cold when singing. One of us requested he removed the balanced traffo to see what the effect was. The transformation was night and day for the better. He has since sold that traffo to another poor soul who only believed in technical specs. So the moral behind don't need to say more right? [END OF QUOTE]

My experience is just the opposite, using a 1KW transformer in the dedicated powerline from the fusebox makes for a positive result. Tested with some friends who could not see me plugging in the mains directly, or through the transformer; they all preferred "with" after a few times replugging.
It all comes down to the synergy between all components imo.
My small tube amp for instance only has to deliver 0,25 Watts for very loud listening levels. The horns have a efficiency of 104Db/1W/1Mtr. So no current-delivering issues here.
As for your problems Chris53 ,did you already try swapping the gear to the other side of the room?
You could also check your interconnects for a bad shield, plus check for any [mini] voltage between the components.

[Deleted]

If you just move the gear a little bit it sometimes alleviates the problem slightly. I did that at first with the Bravos and then the Sunrise until it got fully treated. It was amazing what difference just an inch made.

I'm still not exactly sure where mine was coming from and it surprised me how much it went up and down with small movements.

Tin foil on the wall as a test?

You could always connect it to the tv and pick up Sky TV!