Tube vendor recommendations?

RAM Labs for me too. Roger Modjeski has a vast knowledge of tube design, construction, and performance parameters, as well as amplifier circuits. He often provides tubes to other amp designers such as Mike Sanders (Quicksilver Audio) and Ralph Karsten (Atma-Sphere).

Thanks for these suggestions. 

Another vote for Andy at Vintage Tube Services. Always nice, honest and reliable, and great, well tested tubes.

It’s seems as though Andy and Jim are popular choices here. I know that Kevin at UpScale prefers to serve his customers. Two of the products I need tubes for came from my being one of his customers. That said, I’ll likely call Andy or Jim first.