A DAC, including an RPI as player. Input is ethernet. DAC chip is my favorite, AD1865. From the RPI it fed through an I2S buffer and reclock, than an I2S to PCM converter. That is not my design. The DAC board is my design, at the end, there is no low pass filter, the interstage transformer acts like that. Than, the triode amp and buffer circuit is designed by a friend, I built it on cnc milled plate and point to point wiring. Several modifications made, first I did not like it. It was too dry and sterile. That time the end stage was based on ECC83s. It is redesigned and made with 5687s. Now, it is pretty good. Once I "finish", I will design and get cut and bent a copper case. But now, I'm in a stage that I need a decent headphone amp, tho be able to listen to music when the kids are sleeping in the other room.