/ Home & Energy, Technology

The energy-saving LED bulb that switched off the radio

An LED bulb lighting up the darkness

We get sent some weird and wonderful tales of products going wrong, but one story piqued our interest so much that we just had to send it to the lab to test it out. Can you help us shed more light on the mystery?

Last year we received this intriguing message:

‘I recently changed six halogen down-lighters to more energy efficient LED bulbs. Unfortunately when the lights were switched on, the DAB signal on my radio was wiped out!’

To try and figure out this conundrum, we sent a batch of cheap, generic 12V LED bulbs to our lab and found that when a digital radio was placed within a few metres of the switched-on bulbs the signal went fuzzy. When the radio was placed within a few centimetres of the LED bulbs, it cut out all together.

The plot thickens

LEDs are ultra energy efficient light bulbs that can last up to twenty years and have been hailed as the future of home lighting.

It seems our members are not the only ones who have had this problem. There are other accounts of LED bulbs affecting radios, with AVForums also collecting stories. Nick Tooley shared his experience:

‘I had the same problems with LED bulbs wiping out DAB reception and tried several types of bulbs, but to no avail.’

And it seems that the issue may not just be limited to digital radios – TVs may also be affected. After fitting LED down-lighters in his kitchen, Jackord noticed the following problem:

‘While the lights are much better, we then by accident noticed that the digital TV would not work (I was complaining that we had no reception at all, did not make any sense, began to think that there had been some sort of catastrophic disaster which stopped the TV stations from broadcasting…lol) then someone turned off the ceiling lights in the kitchen and, hey presto, on came the TV.’

Shedding light on cheap bulbs

So what bulbs are affected? We tested three 12V generic LED bulbs and we also compared them to branded 240V GU10 LEDs and some halogens. We found only a very minor interference with our radio signal. So at this stage, the issue seems to be limited to cheap knock-offs rather than branded goods.

We’ve only done preliminary tests on this problem, so can’t make any concrete conclusions on why this is happening or how widespread this bizarre problem is.

That’s where you come in. We need your help – have you had this problem? If so, please enlighten us in the comments below, including what model bulb you were using and where you bought it.


This is probably RF emissions because of badly-designed electronic controllers. The same sort of thing can happen with cheap compact fluorescent lamps – the electronics again. This is why it is worth buying major brands that comply with European Norm standards, including EMC – Electromagnetic Compatability – that are designed to prevent one electrical device affecting another. Sometimes the effect can be inconvenient, at other times life-threatening if it affects medical equipment.

John Dalton says:
28 March 2013

That’s a sensible comment. The only problem is even some well-known branded bulbs marked CE actually don’t comply with the General Directive on EMC. How on earth is the purchaser to know? A recent EU survey found 60% of LED bulbs do not even comply with the various EN standards for light bulbs, let alone the general directive on EMC.

People living off-grid (e.g. on boats) often choose LED lamps to conserve battery power, and they have been discussing the problem of radio interference for years. Even the better LEDs emit some radio interference and it is a case of experimenting to find out which brands work best. Safety is a good enough reason to avoid unbranded lamps of any type.

Whereas interference can be heard as buzzes and hisses on AM and FM radios, DAB radios either become silent or burble if there is too much interference or the signal strength is too low. An outside aerial can avoid the problem and better quality portables will accept an aerial connection (sometimes in place of the telescopic aerial). Combined DAB and FM external aerials are readily available. Using an external aerial does not guarantee protection from radio interference but will probably greatly reduce the risk.

With any radio interference it is important to keep the radio a distance from the source of interference, whether this is a LED lamp, a CFL, lamp dimmer, broadband router, dimmer switch or anything else that could create a problem. Thus it is best not to have a radio beside a table lamp with any form of low energy lamp.

Good points from MalcR and wavechange. It has encouraged me to read further. And now be concerned at the lack of control on poor quality devices sold into the UK. Something for Which? tio get its teeth into?


The thread here starts in 2010 and is very interesting – you will be amused to see how the thread started. There are a lot of links from it of equal interest pointing out other equipment suffering effects.

With LED lamps becoming better and cheaper it is high time that interference is considered by Which? and any other organisations publishing reviews. I agree that it would be a good idea to look into the poor quality products that are sale in the UK, though safety is my main concern.

There may be scope to make radios and other electronic equipment that are less sensitive to interference but cutting down interference (both radiated and carried via cables) is the obvious top priority.

There is little scope to make radio receivers less sensitive to this type of interference. The problem is that the lights are radiating energy at the frequency being received. Removing the interfering signal is rather like trying to remove the milk from a white coffee, possible but difficult and rather expensive.

True if the interference is being picked up through the aerial rather than elsewhere in the circuitry or via the mains supply. You may be able to eliminate the problem by using an external aerial, but that’s not much help to someone like Claire who is having a problem with her clock radio (see below).

Steve says:
17 March 2013

I’m an electrician and I’ve been experimenting (mainly wattage / lumens comparisons) with LED GU10 bulbs as replacements for halogen lights. On one site recently, we installed 6 downlighters in a kitchen and compared the light produced by 4.5w and 6w LED’s in the fittings. One effect we did notice however was interference in the form of buzzing on the radio which we couldn’t “tune out”. The radio was a cheap FM/AM set (not DAB) and the buzzing was worse with the radio in the kitchen compared to plugging it in further away, close to the the DB in the hall by the front door. The lamps were not cheap, they were good quality LED’s manufactured by Megaman. This could be a problem installing these for residential customers, so far we’ve only installed LED’s in commercial premises (no radios there so not a problem) so we will think carefully before proposing them in homes.

A portable radio is very useful for studying the sources of interference. A good example of mains-borne interference is a dimmer switch. Tune in a radio to LW Radio 4 (198 kHz) and you have a crude tool to detect cable runs and not just those on the dimmer circuit. CFLs usually produce interference within a metre or so from the lamp. I am quite surprised that LED lamps produce a buzzing because that sounds like 50 Hz interference. Are your LED downlighters connected to a dimmer? If so, the dimmer could be the source of interference.

I hope that Megaman LEDs are better than their CFL downlighters, which have been widely reported as unreliable.

18 March 2013

I am building a oak framed barn- type, long house. I purchased Ikea lights ( 6 x 12v halogen bulbs) per 8m run of wires, plus transformer. Two sets ran the the length of the main room. My hifi sytem included a Denon TU 1800 DAB Tuner fed by an indoor aerial. With or without the lights on there was no interference of radio reception.

I replaced the halogens with 5watt LEDs and replaced the transformer with the approptiate driver.
From then on disaster. Switch one set of lights on the and the station would be interropted by a series of loud plops. Switch two sets of lights on and the tuner would indicate no signal and cut out completely.

I sought advice from the BBC — not helpful. I contacted the LED light suppliers — they lived in denial.
On a simple evidence basis LEDs affect DAB reception. Using internet forums it became obvious others were having the same problem but very little evidence of a solution.

Today, I replaced the indoor aerial with an external 5 element Triax DAB aerial. Problem solved.

Superb reception with any number of LEDs on.

Any tuner – whether FM or DAB – deserves a proper aerial, so solving your interference problem will also help you get the best out of your equipment.

19 March 2013

Mine was a ‘proper aerial’ supplied with the tuner.

You have demonstrated that the supplied aerial is inferior. 🙂

Ask any competent Hi-Fi supplier and they will recommend an external aerial for best results. It improves the signal to noise ratio.

19 March 2013

I find wavechange’s comments a little patronizing and amusing at the same time.

My reasons for writing were two fold. He misses completely my main point – the subject of this whole blog – in that LED lights can cause significant radio interference. ( as opposed to most other conventional lights). Further, that appart from this blog and one or two others, there is a level of denial that the problem exists and that includes the BBC and certainly some LED suppliers!.

Secondly, I overcame the problem by using an outdoor aerial. I am well aware of the benefit of using outdoor aerials – thank you! BUT, I did not need one at all, until I fitted the LEDs.

PS, I live within 8 miles ofd a quite main Transmitter for this region.

Over and out. Must get on with life, which now includes listening to crystal clear radio transmissions WITH THE LIGHTS ON.

Gerry says:
22 March 2013

It’s generally not a good idea to use a 5-element aerial for DAB. Except in the unlikely event that only one transmitter site will ever be receivable, an omnidirectional aerial such as a simple vertical dipole will be better.

Unlike FM, DAB signals reflected by hills and buildings are beneficial, so there’s no need for directional aerials.

John Dalton says:
28 March 2013

Thanks David Lewis for your information. Both the suppliers to whom I returned MR16 LEDs were in denial and suggested I change my transformers to their own LED drivers. I had no faith in them as for a 50Hz lamp they were proposing a DC output driver!!

The BBC basically say “over to you, sort it out yourself” – this was the end of my discourse with them :-

“Dear Mr Dalton
I’m sorry to have kept you waiting for a response to your query about LED lamps. Having consulted here and with Ofcom and thought carefully through what we can say, we really aren’t in a position to offer specific advice – it’s just beyond our capability (we aren’t a test-house). There is no point in us asking Ofcom to investigate individual cases since we know the source of the problem, and in general we know what the remedy is! Therefore our agreed statement on the matter is given below:


Low-voltage, LED lamps can sometimes cause interference to DAB and FM reception. The problem is worst with 12V types. The more lamps switched on at a time, the worse the problem becomes. This is most likely to happen when LED lamps are directly substituted for 12V halogen lamps, retaining the original transformers.

The Answer

Substituting one make of LED for another may solve the problem, but if not, try a transformer specifically-designed for LED lamps. Mains-powered LED lamps may be less troublesome. It is a complex problem and there is no single solution.

Something which is CE marked may be returned to the supplier if it gives problems. Lamps without a CE mark should not be on sale. Contact your local trading standards office or check: http://www.tradingstandards.gov.uk/index.cfm for further advice.”

I realise this isn’t going to give you any new information and it also doesn’t, of itself, offer reassurance that any interest is being taken in the problem. However the link http://ec.europa.eu/enterprise/sectors/electrical/files/emc/ms-campaign-fourth_en.pdf (PDF) does give more background and shows that this is being examined at a European level, not just UK, since it is unlikely to go away unless some action is taken at a suitable level. To action such changes take time so, for the moment at least, the solution looks as if it will have to lie in the hands of the purchaser.

I’m sorry I can’t give any more specific help on this issue.

Kind regards

Vaughan Reynolds
Radio & Television Investigation Service”

I change all my GU10 bulbs to LEDs purchased from LED Hut. Not only did they cause severe interference on my clock radio ( not DAB), but they failed so often that after 9 months I took them all out and put the original bulbs back. After a bit of a fight LED Hut have given me a credit (it was over £200 worth), but they only sell LEDs so it is wasted money. The bulbs did save electricity but it was not worth it as changing them was not easy and as I get older standing on a step ladder and struggling above my head is not welcome and to reduce this was one of the reasons for changing. Perhaps I should look at a better brand, never thought that the brand was the problem.

Apologies, David. My comments were intended to be helpful.

Claire, brand does make a difference. A lot of cheap LEDs are around (that may not be sold cheaply). Good quality LEDs (and their control electronics) will cost money, so I’d stick with well-known brands, such as Osram/Silvania, Philips, for example. You’ll probably have a better reception if you do find a problem. You should find suppliers through Google.

Claire – I cannot understand why you had to fight with LEDHut when their lamps all have a 5 year warranty.

Rather than write off over £200, you might like to try to push LEDHut for a refund instead of credit that is worthless to you. There is plenty of useful advice on the Which? website. See: http://www.which.co.uk/consumer-rights/regulation/sale-of-goods-act/

If the lamps are failing well short of their rated operating life (likely to be very long for LED lamps) then they are obviously not of ‘satisfactory quality’, assuming that they have not been abused (which would include failure to follow instructions, for example about use of dimmers). Goods must also be ‘fit for purpose’. If another brand of lamp does not create interference then that would suggest that the ones you have bought are not fit for purpose. You could also report the company to Trading Standards and they might take action if they have other reports about the same problems.

Best of luck.

I had to fight LED Hut because I wanted to return all 25 used bulbs without packaging. I had no trouble getting them to exchange faulty ones, but these 25 were not faulty. I did speak to Trading Standards and they said that we had no rights for bulbs that had not failed, we had to treat each bulb separately. LED Hut actually have fantastic customer service and did agree to a credit eventually but there is nothing else I want to buy from this site as they only stock cheap makes (but I didn’t realise this at the time). I did not know that interference was due to them being cheap and I don’t think I even mentioned it to them. The thing that was annoying me the most was having to change them – 10% failure in the first 6 months.

I actually would not recommend LED Hut for anything as they got my order wrong every time. I ordered my bulbs in three separate orders and one order was wrong three times, the other orders wrong twice! They refunded my postage but it was very time consuming. They also duplicated one order and never charged me for it, and I only just stopped them duplicating it again. As they have credited me for the ones they didn’t charge me for I suppose I shouldn’t complain too much.

I have looked today at the Panasonic LED bulbs, which are twice the price, and will probably try these. But due to all the problems I have not really saved any money.

Thanks Claire. I’m sorry to hear the tale but I’m sure Trading Standards is right about that the company is not obliged to refund non-faulty lamps – unless the interference problem makes them ‘not fit for purpose’.

I strongly suggest that you try one of the Panasonic bulbs and see if this causes interference before investing in a batch. If I was buying LED lamps, I would try Philips first, simply because I’ve been impressed by their technology in the past.

Pity about LEDHut. Their website looks quite respectable and I’m impressed that they recommend a relatively uncommon type of dimmer for use with their dimmable lamps.

Please keep us posted.

Josh says:
23 March 2013

Would it be naive to suggest that LEDs cannot be expected to last long without the correct transformer?

See the following: http://www.yourwelcome.co.uk/blog/low-voltage-12v-led-lamps/

Ian B Cox says:
23 March 2013

I sorry for you sis, I have brought my LED’S from China,USA and Australia.
I have had no problems so far, and I hope they last longer than yours.
‘365 digital’ on ebay came from China

B22 5W 360° 108 LED Warm White Corn Light 450LM Ultra Bright Light Bulb 220V from Australia
‘antiquechina2009’ ebay
hope you can get something sorted out

Alex says:
21 March 2013

Like earlier posters I would agree that this is down to the success or otherwise of the part of the manufacturers design intended to suppress the harmonics generated by the high speed switching devices in the electronic controller in the LED bulb. The problem is that 3 x 1 watt LEDs need about 12 volts to run, whereas rectified mains is about 340 volts. Getting these volts down in a cheap, compact, efficient and not too interference generating way, is what the control electronics try to do. Most do it using designs known as a fly-back or buck converters. These turn the power on and off very quickly and use an inductor as a reservoir to smooth out the result. The higher the frequency used, the smaller (and therefore cheaper) the inductor needs to be. But the higher the frequency the more likely it is to generate radio interference. Guess which way the cheaper makes go!

Anyway, even if they get FCC approvals etc., it is likely that such tests do not include the wires running to the bulbs. These, when attached, form excellent aerials to boost the transmission of interference. So, one thing you can try to reduce this is to add ferrite toroids around the mains leads, as close to the bulbs as possible. Ferrite toroid clamps are the things you see on external power supply leads that make them look like a snake that swallowed a rabbit. Unfortunately only available from specialist suppliers (CPC etc.), but I have heard of people using them with success in small airplanes using LED navigation lights to reduce interference with VHF radios.

In EU countries we have the EMC Directive rather than FCC approval. To qualify for a CE mark, a product should comply but in practice CE marking does not even provide the public with reassurance that a product is safe.

With LED lamps becoming more popular, there is an urgent need for Which? and other organisations running tests to provide information about which lamps to buy to avoid interference problems.

Users need to know that there is not much they can do with their radio or TV to deal with interference, other than using an external aerial, and that their receiver must be sited a reasonable distance from any source of interference.

I have been keeping old computer leads and power supplies with ferrites in case they can be re-used if I ever have problems with interference. It is amusing that my computer autocorrects ferrites to ferrets. 🙂

Alex says:
21 March 2013

Prompted by this discussion to follow through a new product announcement to the spec. sheet, I fond a range of LED spots which claim ‘no radio interference’ (energenie4u.co.uk). Now the engineer in me just knows that ‘no’ has got to be somewhat relative here, but they would nevertheless be an interesting product for any Which? labs test to try.

They do list a set of CE compliances and I suspect one of those covers EMC.

On a separate subject, someone mentioned being recommended a more specialised expensive dimmer. Depending on the LED bulb type, this may be counter-productive. The chip sets that have been launched over the last year or so, and which will appear in products reaching the market about now, are designed to work with cheapo TRIAC dimmers and specifically look for the type of mains waveform that such devices create.

CE marking is meant to show compliance with all relevant EN standards (European Norms, like British Standards which they generally replace) including EMC rewquirements. ENs are, in the main, safety standards so, if properly used, protect the safety of the public. Generally major manufacturers will comply, but because the scheme allows self certification, unscrupulous or ignorant importers may claim but not comply.

Which could also look at some myths surrounding LED lamps. Look at the major manufacturers, who have invested heaviliy in LED technology – you’ll find GLS replacements and reflector lamps with efficiencies ranging from 40 lumens per watt to around 70 lumens per watt. These are for “white” lamps of a colour you would like – warm white to cool white, 2700K to 4000K. Roughly like ordinary GLS bulbs to a fluorescent.
Beware claims for ultra-high efficiencies – may not be for real conditions, may be for much bluer-white colours, which will be unpleasant in most situations, may be untrue. Ask yourself how these others outwit the majors.
Dn’t get carried away with the technology. If you just want a general lighting lamp you can get compact fluorescents with similar efficiencies – typically 55-70 lumens per watt – and cheaper.

But if you do buy LEDs, they will last you maybe 7-12 years so why not pay for a decent make? It is not just the LED quality that matters, but life also depends on decent electronics.

Good point about the relative efficiency of LED and CFL lamps, Malcolm. There does seem to be a common belief that LEDs are incredibly efficient.

I expect that when a direct replacement for the good old 100 watt incandescent bulb arrives (at an affordable price) it will be even less efficient than current offerings because of the high operating temperature. I’m convinced that cramming dozens of LED chips into as small a space as possible to produce a plug-in replacement of the light bulb is not the best way forward.

Stuart Law says:
21 March 2013

My experience is that these LED bulbs also interfere with FM reception.

More important is the DANGER which is not obvious to buyers.

There are (at least) two types of in-ceiling fitments. One is shielded with aluminium, and one is not.
I was advised that he latter requires that you use bulbs wich have an integral aluminium shield to prevent the surrounding ceiling from overheating, (e.g. AURORA AU-ALMR16/50 or Knightsbridge L58DAL). (These state aluminium reflector). The former need only an unshielded bulb.

My bathroom has shielded sockets; my kitchen fitments are not shielded. That there are two types is not obvious when purchasing the bulbs, and (the last time I tried) neither a country wide supermarket, nor a countrywide hardware store stocked the shielded bulb. In fact the staff in the hardware store was ignorant of the need, and I suspect so was the supermarket staff, but I couldn’t find any of them.

I get my bulbs from a local electrical wholesale hardware store.

Oh, yes. The proverbial little old lady would, I think, never be able to change the bulbs in the in-ceiling sockets! It takes me for ever and I wish I’d never had them.

I have never been tempted to install downlighters because of the difficulty of changing lamps. Doing the job for old people is quite enough for me. LED lamps should have a very long life, so hopefully that will save hassle.

The danger of overheating and fire is greater with halogen downlighters, due to the much greater power consumption. However, it is important to consider safety with anything that generates heat.

Good move wavechange – downlights, used on their own, are a poor way of lighting any room unless you like shadows cast under your eyes, nose and other protuberances. If used, you should also have light spread around generally – preferably up, sideways and down – to soften shadows. It is a fad, was also fashionable once in commercial lighting as well but bad practice.

Reputable manufacturers produce downlights for recessing into the ceiling that meet fire regulations – e.g. a protective can at the back. Another cause of fire is poor-quality transformers – both wire wound and electronic – used with low voltage halogens, and left unprotected in the ceiling void. Spend money on a quality product. Applies to LEDs as well.

Graham Pickworth says:
21 March 2013

I have 6 Aurora brand led gu10 6watt 3000k non dimmable light bulbs in my kitchen, purchased from Amazon. There is also a Bose vhf radio within 64 inches of the nearest bulb and I get no interference at all. I also have a Roberts dab radio which I held up to within about 2 or 3 inches of one of the bulbs. Once again radio reception was perfectly clear.

Andrew Critchley says:
21 March 2013

I have a lot of Philips GU10 & MR16 LEDs. GU10 are no problem for DAB. The MR16s completely cut out DAB in the next room to the main bathroom on a non-dimable circuit. The circuits in all other rooms do not cause a problem. I have had to take them out except two, which is all the DAB radio can tolerate. The transformers are the same on all circuits so it is a mystery to me.

John Dalton says:
28 March 2013

I’ve seen an EMC test trace for a Philips brand LED MR16 that shows excess emissions at FM frequencies on a test for conducted (up-the-wire) radiation. This test is apparently madnadatory for fluorescent luminaires (does that include the CFL’s I wonder?) but DOES NOT currently apply to LED lamps. The test traces also showed great dependency on input voltage : OK at 11v, failing at 12v, diabolical at 13v (all smooth DC input, a rather benign test?)

Until I read this correspondence I was planning to replace 12V MR16 halogens with mains GU10 LEDS.

The halogens are failing early (3500 hours vs nameplate 5000) and I have had failures of the electronic transformers. If you are going to research the LED/Halogen bulb business could you do enough to rule out interaction between Homeplug Ethernet-over-mains and the electronic transformers. It may be that house mains power is now so ‘dirty’ that it is producing problems not seen in tests with clean power.

The interference being caused by LED lighting units is only one of the potential causes of radio and TV reception problems. The electro-magnetic environment is under attack from a multiplicity sources, it is being treated like the physical environment was during the Victorian period and beyond and if it continues we will suffer similar problems. One of the most significant causes of interference is the increasing use of power plug data transmission systems. These are now being produced with ever increasing data rates and, according to the BBC, are beginning to have an impact on DAB reception. It will not be too long before they interfere with digital terrestrial TV reception as well. Perhaps it is about time that Which? started to include EMC testing as part of its test procedures. I doubt that any product causing pollution to the physical environment would be rated as a Best Buy, why treat the EM environment with any less respect?

Graham Bedwell says:
30 March 2013

When I was a Which subscriber some years ago I urged greater range of product testing including EMC.. (Interference) .After repeated requests I was fobbed off , and no action was taken except I cancelled my membership !
At long last Which has woken up, why has it taken so long ?


Keith says:
21 March 2013

I have 2x TCP 6w LED gu10 The problem I have is when they are switched on and you stand near them or near the light switch I have a high pitched whistle in my digital hearing aids. I look forward to hearing other comments.

That’s interesting Keith. How close do you have to be to hear the high pitched whistle?

European standards require Electo Magnetic Compatibility (EMC) for electrical products to control interference with other devices. EN marked products should not require further testing as they should be in compliance. Products from more dodgy sources may claim compliance but may not comply, or even have been tested. These need to be looked at much more thoroughly. It is not just inconvenient interference that matters, but they may interfere with medical equipment for example.

John Dalton says:
28 March 2013

An multi-nation EC study last year found 60% of CE marked LED lamps did not comply with the standards they claimed to comply with. You can’t rely on the label, it seems.

2Dears says:
22 March 2013

In November we replaced 9 lights in the kitchen with 4.3w MR16 warm white LEDs advanced high power ‘of outstanding performance and quality” for use ‘with an existing Lv transformer’. The DAB radio in the adjoining dining room stopped working immediately the lights were turned on.
The electrical wholesalers which supplied them said it was caused by the drivers/transformers we were using. Our electrician said that changing these would be very expensive and suggested an exterior aerial. Until we read in Which? about this happening to others we thought it was just our problem! Now we’ve emailed the makers of the radio to ask their opinion.

Bob Bohannon says:
22 March 2013

The problem is EMC. Which ? magazine should contact the Lighting Industry Association (LIA) or the Society of Light and Lighting (SLL) or British Standards to seek advice. All CE branded products should be EMC compliant.

Which ? should not necessarily believe all the hype surrounding LEDs, good ones are great and LED will become the solution to most lighting requirements. However the rapid move of the industry from legacy sources such as tungsten, tungsten haolgen and compact fluorescent has allowed room for many exagerated claims. A cheap generic LED GU10 replacement is fairly unlikely to have the performance, of a high quality bulb.

Typical problems would be cold 6000k colour temperatures, rather than 2700k or 3000k desired in a house, narrow beam angles giving poor uniformity of illuminance, poor colour rendering, variations in colour between bulbs, less than claimed lamp life (usually due to poor thermal managment of the LEDs), higher than claim wattage, less than claimed output, poor power factor correction, and poor EMC compliance.

Yes I do work in the lighting industry, but not for a company which makes or sells these bulbs, either good or bad.

bmccann obe says:
22 March 2013


As I said earlier, CE can be self-certified so less scrupulous manufacturers and vendors may claim compliance without foundation. It is a weakness in the system – although anyone so minded can claim what they like. Buy reputable brands if you want to be safe (literally, sometimes).

The self-certification concept allows for the situation that the product is certified by engineering statement rather than testing. Many manufacturers, not just the unscrupulous ones, opt for this approach because the cost of testing can be very high. Even when testing is carried out and the results are within the limits of the relevant EN specification, though, there is no guarantee that the product will not cause interference. The problem is rather like that of manufacturers’ mpg figures for cars, the testing is carried out under artificial conditions. When put into a real world situation the claims may well turn out to be rather optimistic.

Out of interest, the guidance for self-certification states:

“The manufacturer must build a technical file showing how the product complies with the appropriate Harmonized Standard. Most frequently, this will include a test report from a third party test house. Nevertheless, compliance may be justified on the basis of the manufacturer’s own measurements, or even based purely on engineering arguments, without any test results.”

The possibilities for fiddling are evident!

2Dears says:
22 March 2013

The reply from the Pure technical support engineer says: “In the rare cases we have seen when LED lights affect DAB signal this could be due to the shielding on the transformer for the LED lights.” He had never heard of the 5 element Triax aerial and doesn’t know if it would fit the existing radio. Research continues…

Phil King says:
22 March 2013

I installed some 5w 240v GU10 LEDs in the kitchen to replace halogen 12v downlighters. I notice slight interference on VHF FM radio broadcasts. I don’t listen to digital radio. The TV is on a roof aerial and doesn’t seem to be affected. The supplier was Burton Sons Trading Ltd and the brand name is Simply LED. The model description is:
GU10-RCSPOT-WW LED NxtGen Series II Non-Dimmable 22 piece SMD 5050 430 Lumens 50 watts equivalent Warm White.
The box shows “CE” and “RoHS” symbols.
I am delighted with them – they give a pleasant bright light and turn on instantly.

Macelven says:
22 March 2013

I read about this in recent wHich magazine and was intrigued. Does anyone have any experience of LEDs interfering with other audio equipment or affecting voltage in electrical circuits. We have been experiencing the sound dipping on our TV which has a sound bar attached. It just lasts a few seconds but could be several times in an evening so was very annoying. I was blaming Sky and was about to call them when purely by accident I realised the sound dipped when we turned on a light nearby. A few clicks of various switches confirmed that switching on or off of various appliances could replicate the problem- even noticed the fridge compressor switching on could do it. I am currently awaiting electrician visit to check circuits as i was concerned we had a problem in wiring BUT three days ago i noticed that a recently replaced bulb in wall lights was flickering a bit. It was from a new batch of halogens I bought and the first time I’ve used these lights. I removed the bulb and put in a non halogen and since then no sound dipping! Very bizarre so interested to hear others views on this..especially from any electrical experts ‘in the room’!

Gerry says:
23 March 2013

If you’re using an aerial (rather than satellite or cable) then forget the electrician, and instead use the menu options on your TV or set top box to check the signal strength and signal quality on the channels that are affected.

If they’re not close to 100% then it’s probably your aerial system that needs attention, so you’ll need an aerial specialist, not an electrician.

You might also want to check that you’re really tuned to the transmitter to which your aerial is pointing. Some TVs and set top boxes lock on to the first signals that they find and don’t look any further, so you might be ‘eavesdropping’ on weak, poor quality signals from an unwanted transmitter when stronger ones are available from the right one.

Gerry says:
23 March 2013

Just re-read your comment and realised that you’re probably on satellite…

If so, you might want to try powering the TV and satellite box via a filter plug so that the interference won’t reach them through the mains wiring. That’s probably cheaper and easier than trying to fix every interfering device in the house.

It is interesting that only the audio via the sound bar is affected by the problem also that there is no problem with the picture. I assume, since no mention was made, that the audio direct from the TV, with the sound bar not connected, is OK. How is the sound bar connected? Is it a direct wired connexion or via a wi-fi arrangement? If it is the latter then it could be that the wi-fi link is being affected and changing to a direct wired connexion, if possible, would cure the problem.

Macelven says:
23 March 2013

Thanks, yes we are on satellite and the TV and sound bar were bought as a combo before Xmas but the problem only started this year. Sound bar is wired not through any wi-fi. And I spoke too soon as I have noticed we still get occasional dips but not as frequently. Will investigate the filter plug though..good idea, thank you.

Macelven says:
23 March 2013

By the way can you recommend a good filter plug as not sure what exactly I should be looking for! Thanks all..

Gerry says:
24 March 2013

You could try powering the TV, soundbox and satellite box via something like this:-


Can’t guarantee it will work, but worth a try, and cheaper than calling somebody in ! They offer a 28 day returns policy.

Gerry says:
24 March 2013

You could try powering your TV, soundbox and satellite box via a “6-Way Flat Screen and HDTV Surge Protector and Mains Filter”.

Google it – my post with the link is awaiting moderation !

Can’t guarantee it will work, but worth a try, and cheaper than calling somebody in ! They offer a 28 day returns policy.

Macelven says:
24 March 2013

Many thanks – will give this a go before calling in anyone and let you know if it works.

Macelven says:
27 March 2013

Well has been two days since I fitted the surge protector and filter and NO sound drops at all. Touch wood this seems to have done the trick! So a thousand thanks to Gerry!

Gerry says:
27 March 2013

Glad to hear that the filter plug unit seems to have done the trick – happy to have been able to help !

So there seem to be two problems:-

• LEDs and Switched Mode Power Units that aren’t sufficiently suppressed, and radiate interference through free space and / or the mains wiring

• Radio / TV / Audio products that don’t have sufficient filtering against incoming mains-borne interference.

The good news is that it’s relatively easy to add filter sockets to mains-powered equipment suffering mains borne interference.

The bad news is that, other than moving it or using an external aerial, you can’t do very much about free-space interference at the receiving end (e.g. portable DAB radios) and that it can be impractical to suppress every dodgy device in the house that’s causing a problem.

Rather surprising that Philips don’t seems to have done their homework properly. Might be worth complaining to them saying how disappointed you are; they might welcome the feedback by sending you a gift voucher or something !