Ah, that’s what a wall wart is? I thought people were making derogatory slurs towards Wal Mart.
There’s a cleverly hidden graphic in plain sight 
on the label:
In this example, the center pin is plus and the outer ring is minus.
Most supplies will have this graphic in one form or another…
2 Likes
Well, I hooked it up and the radio didn’t power up. Back to the drawing board.
Do you have a DVM? The supply is probably folding back due to the load. I’d bet you need a minimum of 2.5A supply for any conventional dash type radio to fire up…
I don’t know what a DVM is, my good sir.
I have found a 12 volt, 2 amp output chord but have not tried it yet. I think a 12 volt / 5 amp would be ideal? If I could find one lying around… I’ll probably go buy one, then find a free one lying around the very next day.
Digital Volt Meter. Measure the voltage before turning on the radio and then after trying. It may not be the power supply…
Do you have a make and model number for the radio? That could remove some of the uncertainty as to what kind of power it needs to run…
I left it all at work. I did discover 12 volts / 2 amps will power it up. The lights on the radio turn on, etc. I didn’t have speakers on hand. I’m not sure if the low (2 amp) power will affect sound. Not that I’m trying to create an awesome sound system here.
10w speakers will draw 1 amp each when turned up playing Iron Butterfly and it won’t be very loud. Then there’s the receiver, lights, etc so a 5 amp transformer might be the bare minimum needed.
If I knew how to post an I phone photo here I’d show my shop’s “Rat-Rod-Radio.” I had a 12 v television down there until everything went digital and the antenna wasn’t up to catching a signal. My shop is in a walk out basement with a storm proof den. My late wife was one of those who panicked when the “T” word was mentioned so there’s a generator, etc down there.
1 Like
This offers 10 amps 12 V which likely will power the stereo well for $20ish:
AstroAI AC to DC Converter, 10A 120W 110-220V to 12V Car Cigarette Lighter Socket AC DC Power Supply Adapter for Air Compressor Tire Inflator and Other 12V Devices Under 120W, Black (10A) https://www.amazon.com/dp/B07JGS8CN2/ref=cm_sw_r_cp_api_i_KCzCDbPXE74M1
1 Like
I’m taking a leftover speaker to work tomorrow. I’ll hook it up, throw in the Weezer blue album cd, and see what happens.
There’s a guy at work who works on the truck scales, digital displays, etc. He’s supposed to be at my yard tomorrow. He mentioned he had a stash of electronic parts we could raid. Plus he’s actually educated in this arena.
Iron Butterfly. Haven’t thought about them in a while.
Here’s some back-of-the-napkin math for powering your radio. Power (watts) = Voltage (volts) * Current (amps). So if the wall-wart output is 12 v @ 2 amps, that means it can supply 12 * 2 = 24 watts of electrical power to the radio. The majority of the power a radio uses is directed into making sound waves; i.e. the speakers. An IMAX theatre probably has a bank of speakers on the order of 10,000 watts, but 10 watts of sound waves is probably loud enough for a small shop, so a 24 watt electrical supply should do the job.
A DVM includes a volt meter, a resistance meter, and an amp meter, so it’s a pretty handy tool. Can be used to make sure the positive terminal really is the positive terminal, to avoid expensive hook-up mistakes. The inexpensive ones are very accurate these days. I use the one below as my routine go-to DVM.
Thanks for all the replies. The 12 volt / 2 amp chord powers the radio and one speaker. I’m not sure if more amps would equate to better sound? I will probably use another small speaker or two. Small speakers, though.
The next question is how do I want to mount this apparatus? Any suggestions? I’m considering mounting it all inside an old toolbox. Using the outside surface of the toolbox sort of as a dash panel, wiring inside the box. That might waste space, though. Or…I might hang everything free standing under a shelf I built in the shop, and run the wires through some scrap conduit. Open to suggestions. I’m not real creative, aesthetically speaking.
My dad had an old shortwave radio in his basement shop. He mounted it overhead, in the space between a pair of floor joists. That seemed to create a good environment for the sound to reverberate and boost the base response of the speaker.
Well, I finished up the project. The sound quality is good enough with the 2 amp “wall wart”. If you turn the volume up too much, it starts to distort, but it’s good enough that I can still “turn it up to 11” 
. Distortion may be due to the low amperage. Or maybe the cheap GM speakers. I used 2 small speakers out of a small old stereo (that my wife was throwing out because the CD player quit working), 1 speaker that was left over when replacing a blown speaker in my truck, and a 6 x 9 I pulled out of an 03 Malibu. The antenna and coax is out of a scrapped Chrysler minivan.
I didn’t get as clever with the mounting / box as I intended. I’m not creative in the aesthetic sense. So I just built a box to hold it all out of some thin plywood that I had left over from building the shop a couple of years ago. My wife was throwing out the shelf too, so I just hung the box below the shelf. Plus…now I have another shelf!
All I really bought were some finish nails (that I like to have around anyway) and a tube of “liquid nails” (that I also like to have around). I may screw some signs or license plates to it or something. I’ll probably come across something similar to the other junk I seem to like to nail to the shop wall (other photo). But I ain’t painting it. I hate painting!
2 Likes
Before anyone notices, my woodworking skills aren’t great. Jack of all trades, master of none!
Probably better than I would have done. I’m guessing no kids around? Those centers in the speakers would be inverted within minutes if any of the kids I know got near them. They can’t resist stuff like that- like the drink indicator buttons on the soda cup lids…have to push every one…
I have a 13 year old son and a 10 year old daughter. But they’re kind of over the “have to poke everything” phase. My son already poked the 6x9, though! No harm done. I think it takes boys longer to grow out of that “have to touch it” mentality. Heck…I’m still in that phase I think 
You could do as I did when I built a speaker box put some screen wire over the speaker’s
1 Like
Good for you. You’ve built yourself a nice shop radio and kept all that stuff out of the local landfill to boot. Folks in my neighborhood are putting electronic gadgets out on the curb all the time. Keep an eye out, you’ll may find a higher power wall-wart which will give you a little add’l buffer for the stereo’s power needs.
1 Like
Considered it, and may do that. I have some on hand, leftover from making sifting boxes that my kids used to find shark teeth in a creek here in north MS. We do weird things lol. I was afraid the wire might buzz and vibrate, but there’s probably not enough bass to worry about that.
1 Like