not sure how much you want to spend, but i recently built a tube (valve) amplifier from a kit from these people http://www.bottlehead.com/ http://www.bottlehead

not sure how much you want to spend, but i recently built a tube (valve) amplifier from a kit from these people http://www.bottlehead.com/ http://www.bottlehead.com/ - it was about as easy as making something can be (very good instructions) and very enjoyable. [i guess i should add that the lowest price model - the crack otl headphone amplifier - is not suitable for most headphones. so be careful before buying that one.]