Two preamps in PC applications

If you combine the Claro with the Nonsound, it could give you what you want.  Keep in mind that these cheap tube headphone amps are not really full tube preamps.  They run off very low voltage (this one uses 5V DC) and the tubes are really just used for buffer output.

A "real" tube preamp requires a large transformer because the tubes need to be run using very high voltage (such as 250-300V for preamp tubes).  The cheapest "real" tube headphone amp I found is this:

https://shenzhenaudio.com/collections/headphone-amplifier/products/xduoo-ta-05-ta05-6ji-tube-high-pe...

Another option is to get an Asus Xonar Essence Stx sound card.  This has a true headphone amplifier IC as well as a full-size 1/4" headphone jack on the rear.  Then swap out the op amps with something like Burson V6 Classic to give it a warm/textured sound.  It won't be the same as tube, but it will definitely be warm and high quality.