@rivinyl Ray Tubes are manufactured by Psvane in China. From Ray:
We partner with various contract manufacturers to produce our tubes. In the case of the RESERVE KT88 tubes, it's indeed PSVANE that's handling production for us. While our KT88 RESERVE may share some visual resemblance with PSVANE's own products, our tubes are specifically designed to our own bespoke specifications, quality standards, and rigorous production processes.
We maintain strict oversight through detailed quality control measures, which we outline in our QC-focused blog post here: https://raytubes.com/blogs/news/ray-tubes-1-year-warranty-quality-control
The Ray Tube KT88 Reserve looks to be identical to the Psvane Art Series Mklll KT88. I don't know what differentiates the two tubes, but the Ray Tube KT88 Reserve is double the price. As for their one year warranty, Psvane offers this on all their tubes, so it would appear they are the ones actually standing behind the product. Cheers.