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Permalink Reply by Jkevn on December 2, 2009 at 8:21am

If you have the transformer (wall-wart) that plugs in, it should tell you the output voltage, usually ~12vdc. Two of my favorite lil throw arounds are CBG amps made from old comp speakers. They are not loud enough for performing, and dont have the tone & overdrive controls, but are plenty loud enough to play around with.

Find the wire that would plug into the computer's speaker-out, note the polarity and wire it to a 1/4" jack. Done Deal.
I have both of mine running off the AC adapter. some of the circuitry will self destruct if the voltage falls too far below 12v.

If you find a pair of comp speakers that run off the USB port.....those operate at 5vdc, and can be made to work with a 9v battery.

Good luck

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Permalink Reply by Jerryrig240 on December 2, 2009 at 12:47pm

Na.....these are a standard plug.... Not a dc converter plug... They are kinda old school. I have the guts out and plug them I'm. The light comes on but I have not tried playing anything through it yet though........ We shall see... It's a work in progress.

Jkevn said:

If you have the transformer (wall-wart) that plugs in, it should tell you the output voltage, usually ~12vdc. Two of my favorite lil throw arounds are CBG amps made from old comp speakers. They are not loud enough for performing, and dont have the tone & overdrive controls, but are plenty loud enough to play around with. Find the wire that would plug into the computer's speaker-out, note the polarity and wire it to a 1/4" jack. Done Deal.
I have both of mine running off the AC adapter. some of the circuitry will self destruct if the voltage falls too far below 12v.

If you find a pair of comp speakers that run off the USB port.....those operate at 5vdc, and can be made to work with a 9v battery.

Good luck

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Permalink Reply by Tim on December 2, 2009 at 9:34am

i find the better i get at playing the more i like clean any way.

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Permalink Reply by Jkevn on December 2, 2009 at 1:53pm

if it has a regular AC plug on it, there should be a transformer among the guts and a small rectifier circuit. Same story, you can just run the cord out of the cigar box. Be careful, that dog will bite if ya stick yer finger in the wrong place.
I would bet on it being 12v, more trouble than its worth to re-invent the wheel. Put the guts in a box and enjoy.
I used both of the donor speakers on mine since it is a stereo setup, you can replace with a larger speaker and just use one side of the output, but that wouldnt be as fun as free.....

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Permalink Reply by Jerryrig240 on December 2, 2009 at 3:39pm

So, is there no way I can use this setup on a 9 volt....or a few 9 volts....I don't like the idea of anything that I work on being plugged in....I don't trust myself that much yet. lol

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Permalink Reply by Jkevn on December 2, 2009 at 3:58pm

yes...without seeing it, I'm guessing, but here are the basics...
The AC cord should run to a small transformer, that should drop the voltage to around 12-13vac, two smaller wires should go from transformer to a bridge rectifier circuit (2-4 diodes) that transforms ac into dc. Sometimes the bridge rectifier is mounted on a board that is part of/near the transformer.

The trick is to find the point in the circuit where DC voltage is applied, if you know how to use a volt meter, this is fairly simple. At that point you can remove the parts upstream, and add in the supply of choice. A battery pack that keeps you around 12vdc is ideal.
If you can add pics, I can try and eyeball it.
If you blow it up, you aint lost nothing...just don't hurt yerself...if you aint comfortable with it, find a set with a dc converter...much easier.

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Permalink Reply by Jkevn on December 2, 2009 at 4:00pm

If you aint foolin with the circuitry....dont fret over it being plugged in. You can mount that stuff in a box and keep things arranged like they were in the speakers and it will be no prob..

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Permalink Reply by Jerryrig240 on December 3, 2009 at 3:05am

Well.....I had things all wired, but just could not get anything to work...no sound from the speakers, just a little static....so I am guesing there was something wrong with the circuit...that is why they tossed them in the first place I am sure of it. It was geting power from my 9 volt....the green light would light up, but that was it. So......I guess I will find another set of good comptuer speakers next time.

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