FAQ
TL;DR: LED switch‑mode supplies run at several kHz; "The source of interference are these converters." Replace poor drivers, separate them from radios, and avoid shielding. This FAQ helps ceiling‑radio users and installers fix LED‑related crackle quickly. [Elektroda, diantus, post #17988301]
Why it matters: It preserves clear reception and audio on in‑ceiling units like KB Sound iSelect5.
Quick Facts
- Switch‑mode LED supplies operate at several kHz; missing LC filters cause radio‑band noise. [Elektroda, diantus, post #17988301]
- Shielding has small effect because long cables act like antennas. [Elektroda, Rezystor240, post #17024561]
- Replacing the electronic “transformer” with a proper LED PSU or normal transformer is the most effective fix. [Elektroda, elektryku5, post #17024684]
- Place power supplies far from the radio and antenna; tidy routing; test one by one. [Elektroda, Maharadzdza, post #17988153]
- Example system: 20 m of strip, 5 m leads, 600 LEDs/m—plan power and placement accordingly. [Elektroda, Kkkp1305, post #17024679]
What’s causing the radio interference when my LEDs are on?
Switch‑mode LED converters switch at several kHz and spray broadband noise. The noise couples into nearby radios through wiring. Cheap units often lack adequate LC output filtering. "The source of interference are these converters." Replace noisy supplies with better filtered models. [Elektroda, diantus, post #17988301]
Will shielding cables or the PSU stop the crackling?
Not effectively. "Shielding does not pay." The outgoing and incoming cables behave like antennas. They radiate and receive interference. Shielding the box leaves the cables unaddressed. Replace or relocate the supply instead. [Elektroda, Rezystor240, post #17024561]
Should I replace my “electronic transformer” for the LED strips?
Yes. Swap out the current electronic "transformer" for a normal transformer or quality LED supply. "The fight with these inventions is doomed to failure." A proper replacement cures the source, not the symptom. [Elektroda, elektryku5, post #17024684]
How do I pinpoint which device is causing the interference?
Use a simple A/B test.
- Power the radio and turn off all lighting supplies.
- Turn on only the LED strip supply; listen for noise.
- Turn that off, then turn on the halogen/other supply; compare.
This isolates the culprit. [Elektroda, Maharadzdza, post #17988153]
My KB Sound iSelect5 crackles when LEDs turn on—what’s the quickest fix?
Increase separation. Extend low‑voltage leads and move LED power supplies far from the radio and its antenna. Neatly route and secure the cabling. Test each supply individually to find the worst offender. Replace that unit with a filtered model. [Elektroda, Maharadzdza, post #17988153]
Does zero‑cross or “attached at zero” help with LED noise?
No. LED supplies rectify AC then run a high‑frequency converter. "You confuse the concept of power supply with group power control." Zero‑cross control does not stop the converter’s switching noise. Focus on filtering and placement instead. [Elektroda, diantus, post #17988301]
What should I look for in a replacement LED power supply?
Choose a quality switch‑mode supply with proper EMC filtering. Units without adequate LC output filters radiate noise. Prefer models advertised for low interference. Replace electronic "transformers" with these filtered supplies. Keep leads short near the supply and away from antennas. [Elektroda, diantus, post #17988301]
Do any LEDs avoid interference altogether?
Yes. Transformerless LED designs that omit an inverter should not emit radio interference. This is an edge case and depends on the product. Most strips use switch‑mode supplies, not transformerless circuits. Confirm the design before relying on this. [Elektroda, diantus, post #17988301]
Does moving the power supplies away from the radio really help?
Yes. Extend the cables and push supplies as far from the radio and antenna as practical. Organize and secure all cabling. Test one supply at a time and compare reception. Keep the worst offender farthest from the radio. [Elektroda, Maharadzdza, post #17988153]
Do long cable runs make interference worse?
Often, yes. The outgoing and incoming cables act like antennas. They couple switching noise into the air and the radio front end. Shorten exposed leads near the supply when possible. Prioritize clean routing over ad‑hoc shielding. [Elektroda, Rezystor240, post #17024561]
What type of supply should a typical 12 V LED strip use?
Use a typical 12 V constant‑voltage supply for ordinary LED strips. Many finished lamps use constant‑current drivers instead. Mismatching type causes issues or interference. Replace inadequate supplies rather than trying to fix them piecemeal. [Elektroda, elektryku5, post #17024684]
What should I share to get better troubleshooting help?
Provide clear photos of the "transformer" or power supply and of the LEDs. Show labels, terminals, and wiring. Include distances, cable lengths, and where the radio and antenna sit. This enables precise advice and replacements. [Elektroda, elektryku5, post #17024684]
