I have a complete set of replacement PSVANE tubz that I purchased from Grant Fidelity in Alberta for my Yaquin MC100-B that uses KT-88s. They are definitely quality products.

I used the PSVANE replacement set for a month for warranty purposes & then swapped them back to be used as a spare set when the OEMs eventually fail.

I guess that I have a tin ear because I heard no difference between either set of different brands...