/diy/ - Do It Yourself

>>1545102
from experience let me tell you that the design in your picture is GARBAGE for audio (and probably everything else). The op amp will attempt to keep that completely unbiased class B stage happy, but it can only slew so fast through that entire volt or two of dead zone and the result will always be lots of nasty crossover distortion. Even if you strap in a biasing scheme and fancy it up a bit, stabilizing these kind of boosted op amps is a guess-and-check kind of thing with various R and C values in the feedback network. At the same time, I wouldn't trust that a $6 board from aliexpress would sound much better (and if it does, it'll probably burn out or burn the speakers out in short order.)
For a simple project, there are plenty of all-in-one power amplifier ICs in that price range; all you would need to do is solder it to a board with a handful of resistors and capacitors and strap it to a heatsink. If you want to go deep, all-discrete headphone amps can still be very simple and produce completely inaudible levels of distortion at full volume. High impedance speakers makes the job even easier as you don't have to worry nearly as much about loading and subsequent instability effects on the output stage as with 8 or 4 ohms.

Whether you want to rip off a schematic and build it quickly or get lost in some technical reading, I highly recommend a look around rod elliot's site (http://sound.whsites.net/index2.html)) and a copy of doug self's (http://www.douglas-self.com) Power Amplifier Design book.