Highly recommend the Dragon Inspire IHA-1 headphone tube amp. Handbuilt by Dennis Had, retired founder of Cary Audio. He had the LCD-3 headphones in mind when designing this amp.
http://www.theabsolutesound.com/arti...one-amplifier/
He also makes other tube amps. There is a separate long thread on his amps here on AA:
https://www.audioaficionado.org/showthread.php?t=24170