[Hallicrafters] 6SC7 tubes new or used wanted

[w5jo at brightok.net]

I  wondered the same thing some years back.  I replaced a metal tube in some 
receiver because it was very weak.  So I got out my tools and lifted the 
tabs at the base of the tube.

Struggling a bit I managed to separate the metal shell from the base to find 
a small glass tube, about the size of a miniature tube,  inside surrounded 
by a lot  of packing to absorb shock.   So you have a glass tube inside a 
well packed metal frame made to help the tube survive a more rugged 
environment.  At least the tube I took apart was that way.

Jim
W5JO

-----Original Message----- 

I have often wondered about the difference between metal and glass
versions.