So I didn't
And made some.
These are powered by a battery.
They are incredibly easy to make I'm 14 I did it!
As ever I am not responsible if it doesn't work or goes wrong.
Try it at your own risk.
This is easy because the speakers already have and amplifier and controls built in. They are very loud and very clear.
These cost me about £2 (50p for the speakers and £1.50 for the battery) I had a spare connector lying around.
What you need
Some computer speakers powered by the main. ( I found mine at a car boot sale for 50p!!!!!!!!!!!)
Electrical insulation tape or you could solder
A 9volt battery
A 9volt battery connector.
What ever casing/box you want to put it in.
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Signing UpStep 1Getting started
Find the pack that converts the voltage from mains (240) to 12 or whatever the circuit runs at.
cut the cable running between the pack and the circuit board.
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thanks
I wouldn't think so because the voltage will fluctuate as that is what makes the speakers vibrate at different frequencies, and you wouldn't get a clear reading.
Why do you want to measure the output voltage of the audio output?
Matt
Find the biggest capacitor on the board (that's the main filter) and measure the voltage there while it's running. The voltage is different from the transformer output (usually higher) because the alternative current is converted to DC. Don't short any contacts on the board while doing it! That should be the operating voltage. You should solder the battery contacts to that capacitor. Be aware of the polarity! Usually the capacitor has a black stripe (a minus) on the negative side. The transformer on my speakers said 9V output (in reality it gave 10 volts, but under no load). The main filter capacitor voltage was 14V! Though, it should be around 12V under load. (chinese speakers with too small components for it's output).
Thanks
http://www.instructables.com/id/Portable-Tennis-Ball-Speaker-for-Mp3-Ipod/
it is a very good idea to use old speakers!
i have made a crackerbox amp {make magazine vol.9 http://makezine.com }
if you are wondering where to get dead cheap electronics in the UK then visit
www.bitsbox.co.uk. the delivery is just £2.00
i made my own amp for only 7 quid inc. delivery!