I've been using Siemens F2a tubes along with a Spanish Marconi U50/80 rectifier in my TRP since Oct. 2021. I’ve tried many other rectifiers (5u4g’s, 274b’s, 5r4gy’s, Shuguang gz480, Bendix 6106, Brimar CV1863) but I preferred the U50/80 to all of them. After explaining why to Mark Coles, he pointed out the Tungsram PV200/600 and I quickly ordered one (and an adapter). One advantage that this tube has is that it is very reasonably priced. I’ve now had a chance to try it in my TRP and it has become my new favorite. It gives music more presence than anything else that I've tried, and otherwise it is a lot like the U50/80. In my system it’s like a GZ480 but clearer with even more “oomph”.