I had picked up a car amplifier a while ago and found that I had an extra speaker (Polk Audio) that is a different brand than my stereo system (Boston Acoustics). So, I couldn't add it to my stereo--so I decided to build an extra speaker/amp combo that I could than plug into something else at somepoint in the future.
The only thing missing was a power supply.
I bought a 1U power supply from an electronics store for $12.50 because I liked the slim profile and the 12V had a output of 12A. My amp required 88 watts, so this can satisfy that requirement.
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I also needed a load to get it to turn on--I plugged in a harddrive (that doesn't work anymore). This provided the load. Plugging in the power into the 12V output into the amp and the amp into the speaker -- and it worked!
Next, to replace the dead harddrive with a 10 OHM 10 watt resister...