Tubes

[Grbullets2@xxxxxxx]

I have a question about some tubes I recently bought.I found some NOS General 
Electric 5881 tubes which I find give me the best tone out of my bassman RI.I 
assumed they were US made but when I took them out of the boxes,they all had 
5881 Canada stamped on them along with the usual GE logo and writing.They are 
the same size as the US 5881's that I have in my amp although they are a 
little different internally.My US made ones have a black base and the 
Canadian ones are brown.The base on the Canadian tubes has USA cast into the 
bottom.The US tubes have 1 getter on the side as where the Canadian ones have 
2 on the sides.
         Does anyone know if GE produced tubes in Canada?They do not say 
"made in Canada",only 5881 Canada on the tube,or is it possible that GE made 
the tubes in the US to be sold in Canada?If they were made in Canada,are they 
comparable to the US made tubes?I haven't had a chance to try them yet but 
I'd like to know if any of you tube guru's out there could give me a little 
info on Canadian tubes.I've heard alot about US,Russian,and Chinese tubes but 
not Canadian.Any info would be greatly appreciated.Thanks.......Dave