[Amps] 4pr-1000b,Y448 tubes

[Ve6wz_Steve]

I have searched google for details on the diferances between the
4pr-1000b (pulse tube) and the basic 4-1000a and have found limited
information.

My HB 4-1000 amp, GG with 6Kv anode voltage performs well, but just
today realised the tube is an Eimac 4pr-1000b....I can just read the
faint red print.

What "real" difference is realised by using the pulse rated tube and the
"standard" 4-1000a ??

Also, any experience out there regarding using the National Y448 tube? I
have the oportunity to purchase one of those...will they function as
plug-and-play replacements to a 4-1000? Reliable?

Steve ve6wz.