Low Voltage, Tube Driven, Guitar, Headphone Amp: 12K5?

I don't have room for a guitar amp right now so a headphone amp is the logical answer.  I tried to find a tube driven, guitar, headphone amp but no one seems to make such a thing even as a kit.  I don't really have the expertise to design my own circuit but it seems like that's the only way to get one.  Would a 12K5 work for this purpose?  Basically all I want is a beautiful clean sound I can listen to through headphones and I don't really want to run 200V for the purpose, if I can avoid it.  Am I on the right track here?