John Sayers' Recording Studio Design Forum Archive

Hi Guys,

I’ve been reading about EMI and LED lighting and the culprit (it seems) is cheap drivers. I’ll be using between six and nine LED down lights in a 21’ x 13’ project studio (see here). For packaging reasons I’ll be using low-profile units like the attached image. I’ll also have LED’s in the hallway leading up to the studio, the basement stairwell, etc.

I haven’t been able to find any solid recommendations for a specific LED kit that is good for studios, so the thought of replacing the drivers came up. Mean Well reportedly makes high-quality drivers, but my suspicion is that these are for LED strip lights and not down lights.

So a dumb question… Can I take an off-the-shelf LED kit and replace the driver? If so, what specs do I need to look at beyond wattage? Mean Well offers constant-current units, constant-power units, built-in PFC functions, etc.

The only other option I’ve seen for EMI reduction are medical-grade devices which are insanely expensive. I’m going to call Mean Well (they’ll think I’m Chuck McGill), but I think if I explain the challenge they can probably help.

Thanks in advance.

Todd

if you power LED with a clean power supply (which could be isolated), then that would work. the main problem is low cost units often don't do more than is necessary for shielding than the lowest bar in the FCC specifications. another option is to wrap the PSU with shields and ground it.

Hi Glenn,

Thanks for the quick reply.

A few follow-up questions (note that electricity is my Achilles Heal):

When you talk about a clean power supply, are you suggesting an isolation transformer? Most of the units I’ve seen are plug-in units or whole-house units. I’d love to find an individual breaker-based solution or something that I could insert between the breaker and the lights. Does such a thing exist (to your knowledge)?

In terms of wrapping the drivers, are you referring to Faraday-like material? Is there any risk of heat/fire or any suggested tips for how to apply it?

If I chose to ground the driver enclosure, how would I do that? I’m using 12/2 MC for wiring the lights. Would grounding the enclosures entail running a separate ground wire from the driver case to the ground bar in the panel?

Thanks again.

Todd

12/2 seems heavy for lighting. w separate ground should work. the wrap on the units - maybe copper or aluminum tape if they need additional shielding outside of the box they come in. of course this will require empirical testing to determine if the unit your interested in makes noise. a good test is to plug in into the same outlet as a tube guitar amp (or equiv sensitive device) cranked up and vary the dimmer etc to see what kind of hum, buzzes, and crackles happen.

Hi Glenn,

I’ve been working diligently on this and I’ll soon have some results to report. I’ve been using an AM radio tuned off-station to listen for EMI. It’s not an oscilloscope by any stretch, but it should provide a relative observation of EMI through listening. Unfortunately I don’t have a tube guitar amp so this was the next best thing.

My preliminary findings are that digital/LED dimmers *anywhere* in the house can be a big problem. They radiate EMI a long distance (noise from a second level bedroom can be heard in the basement). I’ve eliminated most dimmers in the house and I’ll be doing a comparative test of a few different manufacturers to see if I can find a quieter dimmer in the rare case I absolutely need one.

I’ve ordered several different LED down lights and I built a small test rig so that I can activate them without a true install. Then I can use my AM radio to compare them and find the least interference. The Lithonia units have impressed me thus far, in that the driver and the mini junction box are both grounded (and provide a ground wire for connection to the main wiring). With just these units, I notice very little difference being on or off.

I’ll have a lot more to report in a few days once I do some back-to-back comparisons.

Thanks again.

Todd