110 source to 12 volt appliance

I’ve got a car stereo that I’m not using. I also have a little shop beside my house. I’d kind of like to use that car stereo and a car speaker or two as a shop radio. Nothing fancy, I’m not trying to do anything impressive or achieve awesome sound quality. The walls in my shop are OSB, so I thought it might be fun to recess the radio and speakers into the wall. I’m good with the wiring, will solder the wires and probably wrap with heat shrink. But can someone provide an example of what I’ll need to convert power from 110 wall outlet down to 12 volts? I need to keep the cost below what a cheap boom box costs, or else I can’t justify it. Seems like it would be a decent winter project between more pressing things.

A 120 volt to 12 volt step down transformer, and a full wave rectifier to turn the 12volt AC to DC.

Buy a small battery charger. 2 to 3 amps should get the job done. If you have a bigger one with a meter on it, fire it up and look for draw. Hook a cheap antenna up so it gets radio signals

Nearly every garage space I’ve ever seen when I worked for GM had a car radio hooked up for music exactly that way. Except electonics labs, they used old variable power supplies.


Look in your stack of old power supplies, find one that puts out 12V to 15V DC (some old cordless phones, etc).

Or a cheap power supply from Amazon or… Radio Shack, if they’re still around!


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You can also use an old pc desktop or laptop supply. Wall warts up to 5A can be had for under $15.

I’ve got a scrap “110 to 30 volts, to be used with IT equipment only” chord I’m tempted to use. It’s free and I found it. But I don’t want to burn down the shop over 30 bucks. I actually cut the connector off and stripped the wires. Hmmm…all black is probably ground…

But I haven’t plugged it in. I’m trying to be more responsible these days!

So my initial idea was what twin turbo suggested. The chord I have is pc-ish. I think. But to be clear, do I need it to state “110/120 to 12 volts”?

I can wire stuff. And make it correct, all soldered and heat shrinked. Ask my now cruise control optioned work truck! But I’m not versed in amps, Watts, voltage, etc. beyond the basics. My house is 110. The vehicles are 12 volts. You need a ground. Beyond that, I’m admittedly ignorant.

Do the black boxes on the PC cords step down 110 to 12 volt? I work at a scrap yard for goodness sake. No sense buying anything.

Recycle! Lol.

JP, what do I do with a piece like this? Strip the wires and hook it up? Positive to positive, ground to ground?

Before you hook it to anything, connect the stripped leads to a voltmeter and stick the plug into the wall, most computers are not 12volt.

I have a bunch of old 110v ac to 12 volt dc. See what amps you need for the boom box. Watch out for switching transformers, I blew up a CD player with one, right voltage, but smoked it good. Too many amps is fine, it will only take what it needs in my experience. A car PowerPoint socket and plug wired appropriately. is my preference, available then for other use or testing as needed.

If I do smoke the car stereo, no big loss. I just want to avoid a fire hazard. I’ll check the voltage on the stripped leads tomorrow. I left the apparatus (unplugged) at work.

I have a cardboard box filled with wall-wart power supplies I’ve used or found over the years, so that’s where I’d start looking if I wanted to do that. Googling “AC to DC converter” would probably turn up a bevy of economic mail-order candidates too. If I couldn’t find the correct volt/amp wall-wart combo I’d probably use a recycled desktop-PC power supply. Folks put their old no-longer used PC out on the curb all the time in my area, for anybody to grab. Some caution is needed for the latter, as many of those desktop PC power supplies were built on the cheap to keep the computer’s price low, and therefore using an old one could potentially pose an electric shock hazard.

I’ve been thinking about doing the same thing. My unit with a CD, Tape, and AM FM is to the point where nothing works except one AM and one FM stations. I’ve got it wired for the garage and shop just using a switch. Can’t find anything at a reasonable cost with the features that will fit my space. And I would like to be able to listen to CDs again like Bob Dylan. I recently just got a TC Atlantic CD from the 60’s and had to go for a drive to listen to it. A former Minneapolis band. The only thing I bought it for was “20 years ago in Speedy’s kitchen”.

This one is a little pricey (around $200) but has really excellent fm tuner, and the sound quality is superb. Includes an mp3 decoder for the CD player, which is very handy when listening to a multitude of mp3 podcasts written to recordable CD’s. 30 or so Car Talk podcasts will fit on one CD. There’s a version without the mp3 decoder for a little less $$.

There’s some cheap 110 to 12 volt/5 amp converters on eBay. Failing that, what about a 20 dollar lawn tractor battery and a trickle charger if you don’t have one?
The trickle charger could also be used on other vehicles of course.

I believe I’ve found what I need?

I’m not sure which wire on the plug is positive. I’m afraid if I hook it up backwards all of the rock stations will just play satanic messages.

Anyone else remember that? Play rock music backwards…:thinking:


Will 1 amp operate the radio?

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That wall wart only puts out 1 amp. Might be a bit low.

Err…good question. Did I mention I was electronically ignorant for the most part…?