The objective of the project is to create a 2-stage hybrid headphone amplifier where the voltage stage uses a vacuum tube that feeds a MOSFET follower output stage with low voltage while both are ...

The project is known as NP-100v12 which refers to a simple headphone amplifier built around the 12AU7 vacuum tube. The 12AU7 is also known as ECC82 in Europe that is popular in the audio world since ...