Hannah 🐝HiFi beats to ignore work to.
This is my TA-26 headphone amp, which is an output transformerless (OTL) tube amp. It's made by a Chinese company called xDuoo. The design is fairly well known (see Darkvoice 336 or Bottlehead Crack) with a 6AS7 at the back and a 6SN7 at the front.
I have a NOS (new old stock) Mullard 6080 in the back and a NOS Sylvania 6SN7GT in the front.