This Amp3 is one of the amp models from 41Hz Audio. I have my eye on the Amp7, this looks like an interesting design.
“I have to say, for $25 it puts out some awsome sound!
Takes a few hours to put together though.
You have to wind your own torroids.
I used 15-minute epoxy to ensure the torroids will be solid in the car.
25-watts per channel at 4ohms.
I can reach about 75 volume on the FM radio I am using to test with before distortion.
That is beyond tolerable levels anyways. ”
Via: Make