Couple days ago I finally started to build the headphone output part for my amplifier project that I have slowly been working on.
Earlier today I completed that part.
It is somewhat overkill, because it can deliver some 20W peaks into 32 ohm headphones given loud enough input hahahaha. The gain is set low enough that there aren't going to be any headphone blowouts with normal input levels, I didn't bother adding any current limiting to the design.
You can drive 4 ohm speakers with it and then the heatsink actually gets hot, around 52ºC with very bassy tunes. With headphones there is no meaningful heat generation. Distortions are inaudible, and the distortions that start appearing at high levels are caused by headphones not being able to keep up with the output swing lol.
The black box seen is the on/off protection relay. Control circuit which also handles speaker output protection ands witching is not visible. The two switches are actually speaker outputs controls.
Eventually I'll add proper shielded wires for the input, I haven't yet built the tone controls stage.