I just have to say that this type of comment is what is killing hi-fi.
Audio is totally subjective. Tube audio does not "measure" better than SS, but it totally kills SS in sound quality. People need to stop spending time with graphs and measurements and more time auditioning amps and headphones themselves.
As for amp, I know of someone who would be willing to make a custom tube amp for your price point.
If you don't like that idea, then go on ebay and look for a used and abused jolida glass tube FX amp and then get a speaker amp to headphone amp adapter.
The lyr is a hybrid amp and does not have that much of a tube amp sound to it. You will spend a lot of $$$ on tubes and you won't get as much benefit as you would with an all tube amp.