I have 6 mains (240v) downlighters in my kitchen controlled by one wall switch. When they are on I get a earthloop type hum when using my phonostage. Lights off, no hum.
I assume that there is a SMPS inside each LED lamp which is causing the hum. Any ideas (other than a dark kitchen) to suppress the hum?
TiA
I assume that there is a SMPS inside each LED lamp which is causing the hum. Any ideas (other than a dark kitchen) to suppress the hum?
TiA
You need to see exactly from were the hum it is coming.
It is radiated or it is conducted?
To reduce (to check this hypothesis) the radiations you can put a metallic box over light source, but I do not know how big there are. If you have many, disconnect all except one and the last one cover with some metal (grounded). If the problems are radiations, it is not so easy to solve
If are conducted hum, you need to put a filter on the lines of the light source.
Usually there are a combinations of this two cases.
best regard,
Bogdan
It is radiated or it is conducted?
To reduce (to check this hypothesis) the radiations you can put a metallic box over light source, but I do not know how big there are. If you have many, disconnect all except one and the last one cover with some metal (grounded). If the problems are radiations, it is not so easy to solve
If are conducted hum, you need to put a filter on the lines of the light source.
Usually there are a combinations of this two cases.
best regard,
Bogdan
Other people have reported that LED lighting negatively affects their sound system. (As I am in the process of building a new house and new housing has to use LED lighting - I am not looking forward to hearing the result! Greenies have a lot to answer for, IMO!
)I think you are correct - it is the SMPS inside each LED light which is causing the problem. However, I suggest it is not radiated hash - but hash introduced into the mains wiring ... and your phono stage is most susceptible because of its high gain.
So my suggestion is to put a hash-filter between your phono stage and the wall-socket. Experiments I have done recently here in Oz have shown that Shaffner 2090-1 (1a) do a great job of stopping hash:
a) getting out of components - such as CDPs - which generally have SMPSUs, and
b) getting into components such as phono stages.
Regards,
Andy
Lighting in the UK ALWAYS runs off it's own circuit.
You can insert an effective filter at the distribution board to attenuate (cable fed) interference fed back from any and all lights in the house.
It is always better to suppress interference at source, but for tens, or approaching hundreds, of lights suppressing at the distribution board may be the only economic solution.
THEN add proper and effective RF attenuation at the audio equipment.
I recommend you ensure and RF attenuation filter be fitted to the input of EVERY bit of audio gear you build, not just to Power Amplifiers.
You can insert an effective filter at the distribution board to attenuate (cable fed) interference fed back from any and all lights in the house.
It is always better to suppress interference at source, but for tens, or approaching hundreds, of lights suppressing at the distribution board may be the only economic solution.
THEN add proper and effective RF attenuation at the audio equipment.
I recommend you ensure and RF attenuation filter be fitted to the input of EVERY bit of audio gear you build, not just to Power Amplifiers.
Yes, the lights are running off of their own 5a MCB, which is physically next to the HiFi's 30a MCB in the Distribution Board (the HiFi is on its own ring circuit)
Having typed this I have just had a thought. When we had the loft re insulated, its possible that the HiFi cable was moved which would put it across the top of one or more of the LED downlighters. Before I do anything else I think I'll have to struggle up in the loft and have a look. It might be as simple as the close proximity of the two is causing the problem.
I;ll report back once I have investigated more.
Having typed this I have just had a thought. When we had the loft re insulated, its possible that the HiFi cable was moved which would put it across the top of one or more of the LED downlighters. Before I do anything else I think I'll have to struggle up in the loft and have a look. It might be as simple as the close proximity of the two is causing the problem.
I;ll report back once I have investigated more.
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In Oz, we generally have several 10a lighting circuits. But, yes, they are separate circuits to those for power.
You can - but this will be quite a high-amperage hash-filter (to cover, in my case, ~170 lights on several circuits).
More economic, I suggest, to have several hash-filters (which, in my case, are added to isolating transformers) covering all source gear.
Agreed.
1a Shaffner filters can be fitted to source gear ... you probably need 9a filters for power amps.Andy
1A and 3A IEC filter socket do for much of my gear.
I have a small stock of 6A filters, but have not used any.
One will get used if I ever finish a stereo KSA100 clone (1000VA+1000VA transformers)
a mono KSA100 clone will easily run on a 3A filter. Because it does not draw 4A continuously.
What is the worst case lighting power on one of your lighting circuits?
Most house lighting circuits are fused at 6A.
I have 72 light outlets on two 6A circuits. Before I started adopting LEDs, I never tripped a lighting MCB.
Now you have me thinking !!! Maybe I should add a couple of filters at the distribution board for my lights?
Maybe a really big one for my 3 phases into my garage workshop?
I have a small stock of 6A filters, but have not used any.
One will get used if I ever finish a stereo KSA100 clone (1000VA+1000VA transformers)
a mono KSA100 clone will easily run on a 3A filter. Because it does not draw 4A continuously.
What is the worst case lighting power on one of your lighting circuits?
Most house lighting circuits are fused at 6A.
I have 72 light outlets on two 6A circuits. Before I started adopting LEDs, I never tripped a lighting MCB.
Now you have me thinking !!! Maybe I should add a couple of filters at the distribution board for my lights?
Maybe a really big one for my 3 phases into my garage workshop?
The HiFi ring is well over 30cm away from the LED lights (and can not be moved any further unless it goes outside the house) so I can't do nothing there. The next 'plan' (stop laughing) is to try and see if its radiated. Fun Fun Fun
The lights are not on a dimmer, so it's not going to be that.
The lights are not on a dimmer, so it's not going to be that.
Shame, although most LED lights are pure schlock electronically, either they have a noisy current drive SMPS or a current limiting capacitor which causes them to flicker horribly.
Saw some particularly bad ones last weekend when eating at a burger bar near my uni. Even the slightest of movements were strobed and gave me a bit of a headache, not much fun if you're trying to enjoy your food .
Anyways if your phono stage is picking up lighting noise the problem may be more with your setup than your lighting (even the CFLs that make AM radio unlistenable if they're in the next room didn't affect my setup when I had one in a table lamp about a foot to the right of my TT).
Saw some particularly bad ones last weekend when eating at a burger bar near my uni. Even the slightest of movements were strobed and gave me a bit of a headache, not much fun if you're trying to enjoy your food
.Anyways if your phono stage is picking up lighting noise the problem may be more with your setup than your lighting (even the CFLs that make AM radio unlistenable if they're in the next room didn't affect my setup when I had one in a table lamp about a foot to the right of my TT).
Hm. I admit I don't happen to have a phono stage in my main system, but . . . I have MANY LED lights in the rooms where where the audio equipment lives. 5 5 meter LED strips with dimmable power supplies on dimmers in the living room, 10 11 watt dimmable bulbs in sconces also in the living room. The equipment lives in the dining room, where there are 450 individual leds in home-made fixtures and several R30 16 watt downlight leds, too. All are dimmable, and all on our Lutron Homeworks system. No audible hum at all.
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