Svetlana vacuum tubes are among the best available at any price point, and are a great choice for anyone looking for high fidelity and reliability. We test and/or match our tubes by Gm & Plate Current using a state of the art digital Maxi-Matcher tube tester.
I’ve used them before, I believe they are somewhat over priced for new. I had another pair that shipped fine but 1 of them failed in 4 days. I guess it can happen, that’s why I ordered another pair.