In my theater room I have 8 halogen puck lights that are mostly not working and I want to replace them with LED puck lights. On one side of the room I have access to the wiring in the attic. The string of four lights is plugged into the wall with a transformer. This string is then connected to a light switch in the room. On the other side of the room the wiring is buried behind the wall with no access. I assume it's a similar setup. The adapter is a Westek Model Tw60. 120v to 11.5vac. Can I simply replace the halogen puck lights with 12v LED puck lights and leave all of the current wiring in place?enter image description hereenter image description hereenter image description hereenter image description here

  • I would get replacement LED bulbs for the pucks. There's no reason for a puck to fail, other than the bulb simply burning out. You can easily get retrofits for cheap as dirt, most with AC/DC universal compatibility. Last time I bought some they sold 12 for about $7 on amazon. One was faulty, the rest have been on 24/7 for ~3 years. 11.5v is perfect; they will run a bit cooler and last longer than at 12v.
    – dandavis
    Nov 16, 2023 at 23:17

1 Answer 1


Based on the new power supply picture, the voltage out is AC. This supply may be incompatible with the LEDs, unless the LEDs come with a reverse voltage diode built in.

LEDs have a limited amount of reverse voltage capability: they won't light, but they won't conduct either. However, the reverse voltage is much less than a regular diode, and the LEDs may be destroyed by the AC power supply.

You can get a different power supply putting out 12V DC, then use LED lights compatible with 12V DC (or a 24V power supply and 24V LED lights, but not higher than that.)

If by some chance you can find LED lights that are compatible with an AC supply, then you can proceed.

The position of the outlet with insulation up against the power supply may also be a concern. At least moving the insulation away from the power supply would be a good idea, so the supply can dissipate heat.

  • Thanks for your reply. I posted a better picture of the power supply. I would be replacing the entire light fixture rather than just the bulb. I can unscrew the current puck light and I can pull the wiring out about six inches from the wall to rewire the new LED puck lights. I guess I'm wondering if it matters that the supply is 11.5v and the lights are 12v. You can tell how deep my electical knowledge goes lol.
    – Seth
    Nov 16, 2023 at 20:41
  • Have to edit, the power supply is 11.5V AC. Nov 16, 2023 at 22:09
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    12v DC wall warts are a dime a dozen at resale shops, don't even worry about the old one, it's inefficient anyway.
    – dandavis
    Nov 16, 2023 at 23:16
  • Leave the wiring, scrap the old AC power supplies (or sell them on ebay, whatever.) As @dandavis notes, they are easily/cheaply replaced with 12 VDC supplies. It's the wiring that's inconveniently inaccessible and annoying to replace.
    – Ecnerwal
    Nov 17, 2023 at 2:18
  • Unfortunately I only have access to one of the two power supplies. So I think I'm stuck with the 11.5VAC power supply on at least four of the lights. The puck lights are 20 years old and the casing on six of the eight has become brittle and they have broken when I've tried to untwist them to replace the bulbs. Also, the LED bulbs that I tried were too large and would not fit in the fixture.
    – Seth
    Nov 17, 2023 at 19:18

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