Difference in sound between Siemens e88cc and e188cc?


Interested in user experience with the Siemens e88cc and e188cc. In my rig the Siemens e88cc offers great detail, clarity, imaging, nauturalness and dynamics, but is far less tonally saturated than the Amperex e88cc. Is the Siemens e188cc (forget CCa -- $) better in that regard? How do the Siemens e88cc and e188cc differ in sound?
pmboyd
The Tube Museum entry I hadn't seen. Sounds like a voice of authority. Thanks for the reference. 
rodman
Thanks for the information! In my 20 years of selling old stock tubes I have never seen this tube nor did I know it existed. 
Hi,
I searched for info and nothing comes up that's even more strange,
most propably 1 variant for a true very limited production as before 60's (58-59) Siemens had only d getter on 45 inclined and then straight post.
Nobody has seen it. Rarity though does not mean better sound.
Anything to offer about the Siemens D-getter e88cc/e188cc compared to the halo, solid disk and dimple disk?