VA balanced tube preamp

This is my DIY vacuum tube balanced preamp demo.
Highlights:
Ultra noise-free power supply, tripple-shielded potted toroidal transformer, unbalanced inputs, balanced output, remote control, audio detect, tape/monitor function, switchable gain. Signal path: 4xECC83 + 2x6N6P
Contains Raspberry pi with ES9038q2m DAC hat for dlna audio streaming and airplay.
THD ~0,002% @ 1Vrms

[@JingoLoBa57]

Why don’t you leave it switched on? Switching off and on for tubes is not ideal. Just a demo I guess but not great practice. Then it does take some time for the tubes to come up to stable conditions. Was hoping to hear a longer sample.