[jorts21]

Hi, I have a pair of seven ohm bookshelf speakers and I wanted to turn them into computer speakers. The speakers need speaker wires to work and I wanted to terminate the two speakers to either USB or 3.5 mm headphone jack. What would be the best way to do this and drive the speakers at the same time? Thanks!

 

[OJNeg]

Hold on there. What do you mean "turn into computer speakers"? Do you want to create built in amplification?
 
You can't power loudspeakers with either a USB port or a 3.5mm jack. You need an amplifier. The simplest way to fix your problem would be to get a Class-T amp from Parts-Express, run a splitter cable from the 3.5mm jack to the amp, and then wire the speakers according. If you want to create built-in amplification...that's a bit tougher. I've never done it myself, but I imagine you would have to open up one of the cabinets and mount the amplifier there, then hook up each speaker accordingly. I'm not sure why anyone would want self-powered speakers instead of separates, but that's how it's done normally.

 

[jorts21]

What would be a good amp for around 30$ that good drive two 8ohm speakers? They're not seven sorry.

 

[OJNeg]

Here's the Lepai T-amp
 
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=310-300
 
I own one and it sounds ok. Power output is severely limited (Don't even expect the nominal "20W" into an 8ohm load), but it works alright. I can get it to clip if I push it hard enough, but for a desktop setup it should serve you well.
 
If you want something a bit more robust, I'd suggest the Dayton T-amp.
 
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=300-383

 

[GeneralSmirnoff]

OP, seeing as how the speakers aren't very sensitive and will require power to sound their best, stay away from the Lepai. I have it and it sound marvelous after a few modifications but only for very sensitive speakers. They output power on the amplifier is just too low for your needs.
 
Then again, looking at your budget and seeing as this isn't a major project that your doing, the Lepai may be just right for your needs. Just upgrade the power brick to something better. Mine came with some Vonage adapter and I upgraded it to a bigger, better PSU and it's much louder now.