Try the G.E. black plate triple mica square getter 5751's from the 1950's. A better sounding tube all around than the Raytheons
Raytheon 5751 Versions
Wondering anyone had experience with the wonderful Raytheons
I have the NON windmill Grayplates
What sound difference Are the windmill versiopns
I gather more lush mid band on the windmills.