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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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16th Nov 2022, 4:23 pm | #21 | |
Hexode
Join Date: Oct 2012
Location: London, UK.
Posts: 497
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Re: Valve amplifier picking up EMI/RFI
Quote:
Just get rid of them for your neighbours sake even if they are not the cause of your problem. https://www.ispreview.co.uk/index.ph...-adapters.html |
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16th Nov 2022, 5:41 pm | #22 |
Octode
Join Date: Oct 2019
Location: Stockport, Greater Manchester, UK.
Posts: 1,612
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Re: Valve amplifier picking up EMI/RFI
My neighbour has more powerline extenders than I do!
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16th Nov 2022, 8:10 pm | #23 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,799
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Re: Valve amplifier picking up EMI/RFI
That can be fixed...
Just mention near them that powerline adaptors radiate all their data traffic and that with suitable gear and intent, it can be monitored from several hundred metres... David
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17th Nov 2022, 12:35 am | #24 |
Nonode
Join Date: Dec 2012
Location: Stockport, Greater Manchester, UK.
Posts: 2,085
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Re: Valve amplifier picking up EMI/RFI
I've just installed two super new RFI generators
The induction hob is just wonderful for cooking, can't be left on inadvertently, doesn't even get hot, but when it's on it generates enough 20kHz and harmonics to wipe out LW, MW, and up to 49 meters. A battery charger / pulse reconditioner is just wonderful for charging old batteries and also wipes out the FM band, but at least you can choose when to use it!
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17th Nov 2022, 9:25 am | #25 |
Octode
Join Date: Oct 2019
Location: Stockport, Greater Manchester, UK.
Posts: 1,612
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Re: Valve amplifier picking up EMI/RFI
Update. It turns out it is mains borne interference. The culprit is something in the garden, as turning off this circuit stops the clicking/popping completely. Probably either the pond pump (350W), the filter UV lamp or the pond aerator, but could be one of the connections or the garden circuit breaker. Won't be too hard to pinpoint the culprit now. These will be off during the winter anyway but I'll investigate further shortly.
Thanks for the help. Gabriel Ps: I'd get rid of the fish, but the boss says no Last edited by Gabe001; 17th Nov 2022 at 9:30 am. |
17th Nov 2022, 2:03 pm | #26 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,799
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Re: Valve amplifier picking up EMI/RFI
Starter switch for the UV tube? Tubes and starters have finite lives.
Otherwise you may be looking into the fish's internet connection. David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
19th Nov 2022, 9:08 am | #27 |
Octode
Join Date: Oct 2019
Location: Stockport, Greater Manchester, UK.
Posts: 1,612
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Re: Valve amplifier picking up EMI/RFI
And a picture of the culprit. It's the 24W UV lamp for the pond filter
Do you think it's worth writing this up in the bvws journal as an unusual cause of amplifier noise? Last edited by Gabe001; 19th Nov 2022 at 9:14 am. |
19th Nov 2022, 10:22 am | #28 |
Moderator
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,799
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Re: Valve amplifier picking up EMI/RFI
It's a source of interference not many will think about. People with private water supplies have similar things to kill bacteria in their spring water. EMC problems with valve amps are rare, so it's a tale of successful sleuthing in unusual circumstances.
David
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done |
19th Nov 2022, 11:04 am | #29 |
Pentode
Join Date: Sep 2021
Location: Aabenraa, South Jutland, Denmark.
Posts: 218
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Re: Valve amplifier picking up EMI/RFI
Some time ago I had a lot of noise when listening to FM. I had a hard time figuring out what it could be, since it only appeared sometimes, and always in the evening. The noise made it impossible to use the FM band, especially on the lower frequencies. I was sure it was a charger or the internet router, but disconnecting them made no difference.
It turned out to be a light bulb. Not an LED type, but the one shown in the picture. They are probably cheap production ones, as the supports for the filament tends to loosen after some time of use, and when watching the filament carefully, it actually vibrates a little, probably from the mains frequency. Where the filament strings are very close to each other, I believe they make contact and creating some kind of spark which is not visible to the eye, but certainly audible when listening to FM. Never had I ever suspected a light bulb to be such an effective noise transmitter. Nowhere in the house was it possible to use the FM band when light was on in the kitchen. Jan |
19th Nov 2022, 11:25 am | #30 |
Nonode
Join Date: Nov 2015
Location: Welwyn Garden City, Hertfordshire, UK.
Posts: 2,013
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Re: Valve amplifier picking up EMI/RFI
Fish pond UV tubes with SMPS supplies create many spurs on the 70MHz band all spaced 35kHz apart.
On the incandescent bulbs there is some VHF oscillation mechanism that happens with them. https://www.ofcom.org.uk/about-ofcom...rference-issue |
19th Nov 2022, 11:44 am | #31 |
Octode
Join Date: Oct 2019
Location: Stockport, Greater Manchester, UK.
Posts: 1,612
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Re: Valve amplifier picking up EMI/RFI
You know what, reading the article I think that's the same light bulb Jan pictured in her kitchen in the post above yours.
We actually have one similar to that in the house, in a Tiffany type lamp. Luckily it's hardly ever on. |
19th Nov 2022, 1:58 pm | #32 |
Pentode
Join Date: Sep 2021
Location: Aabenraa, South Jutland, Denmark.
Posts: 218
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Re: Valve amplifier picking up EMI/RFI
That is indeed the same type of bulb. I had no clue they could emit that amount of RFI
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22nd Nov 2022, 10:09 pm | #33 |
Triode
Join Date: Dec 2021
Location: Thornbury, South Gloucestershire, UK.
Posts: 30
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Re: Valve amplifier picking up EMI/RFI
Interesting stuff. I have a couple of Radford valve amps that pick up RFI quite badly from an ethernet power line box. Where as the Leak ST20 is completely silent.
I was going to try swapping a couple of valves around in the Radford, but as the interference is a similar level on both channels it would suggest that it is mains bourne. I bought a couple of ferrite clamps for the Radfords mains leads, away on holiday atm so no chance to try yet. ...we have a UV in the pond pump... |