One tube glows brighter than the other

[-Russian-Spy-]

  I recently completed the project, however one tube does glow a bit brighter than the other, is this normal? The amplifier passed all resistance and voltage checks

 

[Paul Birkeland]

Yes, this is a normal variation in tube production.  There's a cathode sleeve over the glowing part, and it's made much longer than it needs to be, but it doesn't always get positioned in exactly the same position.