my friend wants me to change his little Squier SP-10 practice amp to a be battery powered. Any one ever looked inside one and thought about it?

.... battery powered......?

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The parts will cost you more than a DC amp. Tell him to look around on line and there are lots of them. $50. or so.

It would be a simple process but the parts wouldn't be worth it.

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The conversion would be easy if you happened to design switching power supplies for a living. (what I do) If you don't know what you're doing, you don't want to do it. I'll put it on my list of possible projects. I've got an sp-10 that's collecting dust.....

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2002 mim Telecaster
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2 kids (not for sale)
1 wife (uh....no comment)

Ok, curiosity got to me. I'm going to tell you just enough that if you are electrically savvy, you'll know what to do.

First, the ac comes through the switch and onto the main board to the fuses then back to an isolated 60Hz step down transformer. The output is a tapped +/- with the center ground. That's the easy one to measure as it is true chassis ground. The output of the full bridge rectifier circuit (4 discrete diodes) goes to 2 output capacitors. They're large and obvious and have the - marked clearly. By looking under the board, you can see that one is below ground and one is above. I measured the voltages and you have +15V and -15V.

I thought about adding pictures, but since the ac mains are easy to touch on the main board, I won't. So you'd need either a couple 15V batteries or whatever battery you happen to have and build an inverter and a boost (assuming the battery is less than 15V). Total input power listed is 22W, so I'm going to say that the loads are balanced and each converter pushing 1A would be more than adequate.

_________________
2002 mim Telecaster
Jimmie Vaughan Stratocaster
Mexican HSS Stratocaster
6 non-fender guitars
2 kids (not for sale)
1 wife (uh....no comment)