[37silverstreak]

Thanks for the info Ron! It's nice to have an example of both types.
I've done a little reading and I found out that the extra socket in this set is for a ballast tube. the 38 uses a jumper across the filament terminals and is for use with a 2v filament battery. I'm guessing there was a special battery pack as my new 38 has a socket connector on the battery cable. There is also a 38A which uses a type 6 ballast tube which is for use with a dry cell type A battery. i'm not sure if they mean 2 1.5v batteries connected in series for 3volts that the ballast tube drops down to 2 volts or what? I typed in type 6 ballast tube on Ebay and someone had 2 NOS Philco balloon shaped type 6 ballast tubes for sale for like $13 bucks so i bought them. They are pretty cool! I've never a glass ballast tube before, just the metal shell ones. Thought I would use them in my sets and turn them into 6 tubers! If anyone has any info on the 38A model, i would like to hear more about it. Thanks!
Kevin