Do all tubes glow


In my CDP the two 6922 tubes glow and the two E83CCS do not glow but are hot, and the unit seems to play fine. Thoughts?
jl35
Just looking at old threads. Looks like we do. The lack of glow worried me at first. Never saw a tube not glow 
Some tubes do not emit  a glow.
My EML  XLS and Takatsuki  300b tubes don't.
They both sound  superb regardless.
jl35,
What tubes are you using?
Currently I've got a pair of old Mullard 12AX7 and a pair of Telefunken 6922. Figured I'd let the English and Germans fight it out one more time in my CDP.
Starting with a new Jim McShane set of Gold Lion, have some Baldwin and Nat'l Union to try. I'm new at trying tubes...awesome CDP