Difference in sound between Siemens e88cc and e188cc?

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?

HI,
Never tried a d getter Siemens E88cc so don't know their signature. I haven't seen same brand E188CC and believe never existed as E188CC came later. 
Dimple disc has a softer sound on top except the Mullards and is common in Philips family tubes.
Generally Halo getter or round getter has more pronounced mids and d getters are sounding more extended on top.
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