So, I'm going under the hood of my home-brew 5Y3 to put in those rectifier backup diodes (one of RobRob's preventive maintenance items). Now, I'm thinking, if this is such good preventive maintenance, why not do it for my SFPR and SFDR, both running 5U4s. So... inquiring minds have toask: Why is this mod usually mentioned only with the 5E3?? If applicable beyond the 5E3, is the 1N4007 diode sufficient to handle the higher B+ seen on on these silverfaces? Cheers, D.