This one was made around 2000.

This is a headphone amp for high impedance headphones.
It’s built based on “Brute force in a linestage” by Eric Barbour. But the power supply is different, built with the parts I could get. Simple: a mu stage with parallel 6sn7 in the bottom part, parallel 6bl7 on top. With a good output cap, perfect for 300ohm phones.