Edited in response to ThreePhaseEel's note below.

Can I simply try to find a way to wall mount one of these female adapters into the wall, and then run 18 gauge wire from the back of this device to the back of the amp? Not sure how I would wall mount this female jack, and I presume I need to do it in a box, but all that is doable if I can find the right mounting system.


I have wired speakers in my wall. I bought a small amplifier that can be installed in the wall in a 1-gang box. I posted a link below. The unit is 12v DC and can be powered in either of two ways -- there is a jack in the front for a plug in adapter that comes with the unit, or it can be hard wired with DC 12v power in the back. I'd like not to have a cord running down my wall, so the question is, how to power it from the back?

I was thinking there are a couple of options. First, I don't mind having a 12v plug down lower in the wall behind a tv stand. So, I was wondering if there's a way to wall mount a DC power input jack next off the floor near an existing plug, plug an adapter in there, and then just fish 12v wire behind the wall up to the back of the amplifier. But I can't seem to find anything like a 12v wall mounted input jack. It looks as though there's no code problem running 12v wire behind drywall.

Option 2 would be to figure out a clean way to install a 120 to 12 power transformer and then run DC wires from the transformer through the wall to the back of the amp. But I can't figure out the right way to do that either. There are a couple of nearby outlets to take power from if I could figure out a clean solution for my transformer, but I'm not seeing anything. There's one company that sells a small transformer that can supposedly fit in the back of a 1 gang box, but I'm skeptical that it's ok to put a transformer in the wall, even in an accessible junction box, and it does not look like the device is UL listed. I do not have an attic or basement. Have to do everything inside the walls. Is there a transformer that will fit inside an old work 1 gang box? I'm ok having a blank cover on the box to make it accessible. Anything else I could do?

Amp: https://www.amazon.com/gp/product/B010U5EGKE/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

In gangbox transformer: https://www.solidapollo.com/in-wall-power-supply-12v-0.2a-9w.html?gclid=Cj0KCQjwguGYBhDRARIsAHgRm4_BTwKNCmUcYjKKa5wMQwn3KfSCcSZVgmBz9atsmHIYZXxiqqkwDG0aAgHGEALw_wcB

  • 1
    The product you're looking for is called a "barrel connector" and can be found in keystone faceplates which are modular. link However, this has turned into a shopping question which is off-topic here so I'm voting to close the question. Commented Sep 8, 2022 at 14:49
  • Ok, thanks very much -- I still think there's a nugget of a question left, which is whether there is any code prohibition on me running 18 gauge wire for dc behind drywall if both ends are terminated in a box. But other than that, I agree it has run its course.
    – Larry
    Commented Sep 8, 2022 at 14:58
  • Low voltage wiring is outside the scope of code, it does not even require boxes. You might want to label the cable so even potential future inexperienced DIYers don't try to use the wiring for mains runs, but afaik there's no requirement to do so. Commented Sep 8, 2022 at 15:37
  • Thanks all -- I appreciate it. I hope this is a question that may help others with similar projects.
    – Larry
    Commented Sep 8, 2022 at 15:54

1 Answer 1


That supply is way too small

The supply you linked is far too small for your amplifier (200mA max output vs a minimum input requirement of 2A, and perhaps more). You're going to need something far beefier, and likely UL listed to UL 508 (as those are the only listed hardwired supplies available) as well; fortunately, these are fairly standard industrial control fare, and AutomationDirect has one (the PSL-12-060) that'll fit the bill when mounted in a 120mm or 125mm square, 67mm deep or greater (4 11/16" or true 5" square box, 2 1/2" deep minimum) box. (There are other parts available from other vendors/manufacturers, but they're likely to be larger and/or more expensive.)

If you want to use a wall-wart...

If you want to use a remotely located wall wart to power this, you're in luck. You can use a keystone barrel jack in a matching wall plate at where you want to plug in the wiring, and then use standard NEC Class 2 wiring (18AWG bell or thermostat wire) to connect it to the amplifier.

  • Ok, thanks very much. I think a box that big is impractical. So, I guess that leads me to option number 2. It's a little hard to describe, but basically the amp comes with a plug in power adapter. I don't mind having that plugged in behind a tv stand. Is there a way to mount a simple female plug in jack behind the tv stand, and then simply run wires behind the wall to the rear inputs of the amp? Seems like it should work, but I cannot find anything like a wall mounted DC input jack on the internet. Edited to add a product above.
    – Larry
    Commented Sep 8, 2022 at 14:39
  • @Larry please ask that as an entirely new follow up question. Appending new questions to an existing one (as you've done) is not how things are set up to work here and makes it difficult to figure out what's what. You might get a whole new answer to your second question, then which one would you accept? Which one would a future reader look at? You can certainly include a link in your new question back to this one for background and reference - that's actually very helpful.
    – FreeMan
    Commented Sep 9, 2022 at 12:34

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.