[Boatanchors] 5R4 Variants

[Richard W. Solomon]

My Viking II has two 5R4GYA's as rectifiers. The filament on one is
much darker than the other (when lit). So, I thought a fresh set would
be in order.
I see several different variants of the 5R4. Is one type better than the
other ? Any difference in Filament current ? I don't want to fry the
old filament transformer !!

I guess I could look them up in a tube manual, if I still had one. They
all were in the half of my stuff I gave away before I moved.

73, Dick, W1KSZ