My fender tube amp's tubes glow orange, is it normal?

Question

Its a very old amp.

Answer 1

orange is good, blue is not.

Answer 2

Yes...you may continue rocking now...

Answer 3

Tubes work off of what is known as thermionic emission.  Basically, you heat a metal enough (filiment or cathode) and the free electrons come up off of it in a little cloud.  These move easily through the vacuum in the tube toward the positive "plate" or anode.  The center rod or "popsicle stick" looking part of the tube is the cathode.  It is normal for it to glow dull red to bright orangish.  The "curtain"  that surrounds the cathode - the plate - should NOT be glowing at all.  If it is, the tube is badly out of proper DC bias.