Here is my MassDrop Cavalli Tube Headphone Amplifier. It’s a good product, though one for only a small selection of audiophile. A great, relatively inexpensive way to dip into the tube world. Fun to compare with solid state. Though not as warm as I like, and not as warm as a true power tube power amp. Headphones though are great, and easy to enjoy at relatively lower costs.
Massdrop Website: https://drop.com/buy/massdrop-x-alex-cavalli-cth-tube-hybrid-amp?referer=4TGBKN