Author Topic: 12 volt DC Amplifier for Computer Speakers  (Read 2110 times)

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Offline WooferHound

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12 volt DC Amplifier for Computer Speakers
« on: February 09, 2012, 01:45:19 pm »
I have been thinking about how I can use more of the 12 volt power from my RE system. What about upgrading my computer speaker system, from just Millawatts into a couple of 2 inch speakers. A friend of mine gave me some Radio Shack Optimus speakers, They are 2-way with a 4 inch woofer and a Linaeum tweeter, They really sound good for their size with lots of bass and clear high frequencies.

So I wanted a really good amplifier to power them with, and it need to run on 10 to 15 volts from my Solar Power. I ordered a stereo kit that puts out 6-10 watts a channel depending on a power supply that can be anything between 8 and 18 volts. Here is a link to the kit that I built.
http://www.electronickits.com/kit/complete/ampl/k143.htm

After I was finished soldering up the PC board I mounted it in a chassis that used to be a stomp box guitar effect. Here is a picture of it working on my computer desk.

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It only has 3 controls, a volume control and 2 switches. One switch chooses between 2 stereo Phono jack inputs. The other switch sends the output to speakers or a headphone jack. I have always hated to need to plug or unplug the headphones when I wanted to to choose between the speakers and headphones and I do really like having this speaker output switch.

I have been using my new computer speaker system for about a year now and I am very happy with the results. It gets hugely loud with great clear sound quality. It pulls 70ma on idle and I have seen it pull as much as 2 amps on peak loud music. The negative side of my 12volt system is grounded and this caused a loud ground loop hum when I first hooked it up, but I had a couple of audio isolation transformers that I put between the computer and my new amp and it stopped the hum totally.

The power was off for 5 fays after tornadoes in April 2011. I hooked a Battery powered CD walkman up to this amp and was rocking to the classics of the 80's the whole time.

I'm going to crank it up and see if the cops will come and shut me down...
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