A few months ago, a friend of mine gave me his old M-Audio AV30 speakers because the left side no longer worked. Once hooked up to my computer, the speaker sounded great, the down side was that sound only came from one side. The AV30 speakers are notorious for blowing out the left channel due to the amp and circuitry being inside that particular side. After reading through forums it seems that this was a typical problem with these speakers in addition to overheating.
I checked out E-Bay for anyone selling the left side, hoping I could just replace the left side. Someone was selling a pair but the auction included a Lepai LP2020A+ amp. This guy rigged the speakers with an external amp, bypassing the failed built in circuitry.
I googled Lepai amp and it seems like this was a popular amp for cheap or DIY speaker projects.
I ordered one through Amazon, hooked them up, and it didn't work. The problem was the left speaker was active and wired to be powered internally and only output to the right speaker.
Here is how I converted it to become a passive speaker.
Open up the speaker.
Unsolder the red wire that connects the speaker terminals from the board.
Solder that wire to this spot, near where the crossover components are for the tweeter and the woofer.
I actually bought a soldering iron and tested my soldering skills.
The red wire was too short, so I cut some speaker wire and extended it. Yes, that is duct tape, I know...I couldn't find my electrical tape and was too late to run out and get some.
Screwed the speaker back together, hooked up the amp, and I put new life into these old speakers.
The Lepai LP2020A+ amp works well, tiny, but pumps them pretty loud. There is a bypass switch to either use the bass and treble tones on the amp too.
At first I thought I was forced to lose headphone use now that I was using this amp. BUT, there is also a 3.5mm input in the back where you can plug in an mp3 player, etc. I plugged my headphones in, and what do you know? They worked! You don't have volume control for the headphones, but that's ok with me.
How did I know where to solder the wire?
Thanks to these guys:
AV40 Easy one wire fix and http://skralljt.info/?p=740
The only part I didn't do was "cut the trace". I'm no electrical engineer (that should explaing the shitty soldering work and duct tape). So please let me know how critical that is.
Youtube Lepai LP2020A+ and you'll see what this $20 amp can do. I suggest you go out and get one and some bookshelf speakers for your computer set up.