Class A Headphone Amplifier
The original text doesn't recommend heat sinks on the transistors, but I don't agree. This is a class A amp, which means that the transistors work whole the time and they become very hot. If you don't want the risk of burned transistors, you would mount heat sinks!
The power supply shouldn't be too small. Give the circuit lots of power, and it will take what it needs.
Robin Tomtlund