I had several russian tubes 6N23P to build headphones amp. The original circuit was taken from here
One of the problem it was a high voltage power supply, because tube transformers is not cheap and hard to find now. So I decided to use voltage multiplier with mosfet filter for the anodes. The schematic is attached:
Electronic Circuit is a good site for hobbyist also who would like to try DIY because it shared good circuits. If you have a personalized circuit requirement you may feel free to request it through the comment box or contact me.