Which has richer tonality, the Holland e188cc or the USA 7308?

Hi,
depends where you want to use them for, and believe that 1960-1964 are the ones to seek. USA 7308’s cannot go wrong, are nice, quiet with very good bass but a bit relaxed on top always leaving something to be desired. Holland ones sound more complete with a bit better attack and sense of flow. Between the 2, Siemens E188CC fills the space nicely with great bass and livilier top.
More effortless sound, flow and richness comes from Holland D-getter 1960, otherwise any VR5 O-getter (generally my favourite E188CC) will do. Even though Holland ones are branded as Philips Miniwatt, Amperex, Valvo, Dario, RT..i would search for Philips Miniwatt SQ or Amperex PQ with 2 stars on them (i’ve seen only 1963). And now to make things more complicated try to listen to some 6N23P (not EV) Voskhods from 1975-1976 NOS, they are fit and forget with the best flow, soundstage and presentation of detail, they do not last as long as the E188CC, can take abuse have the lowest running temperature and are cheaper. Anyway these are the ones i use in my line stage and Hollands or Siemens in my phono stage-depends where you want to use them.

petg60... In my system the USA 7308, although having great clarity and spatiality, is too lean and edgy, not at all relaxed on top. I prefer the rich tonality and more relaxed white label USA 6922. I'm looking for something with the richness of the 6922 but more articulate and airy. Moreover, the 6922 has better midbass than the 7308, whereas the 7308 has better low bass. It would be great to have both -- a more balanced low end.

Hi,
i prefer the 6922 PQ white also, i am refering to 7308PQ white label made up to 64. Greens, Oranges are different to me. 

@petg60 , I agree to go for the white label.
I've been following @pmboyd 's quest for a specific sonic signature. I like the 7308 Amperex PQ/Philips SQ Holland large O-getter for it's transparency, warm liquid mids, deep low-end, and smooth extended highs. Not a rich sounding tube. 
@pmboyd , maybe you would like the D-getter version, although hard to find.

@pmboyd , have you tried a 6922 PQ Holland?

From Brent Jessee...
Fabulous original 1957 D-getter vintage white label Holland made PQ type Amperex tubes, and have the rare, indented glass midsections ("pinched waist")and wider bottoms that are famed for ultra-low microphonics. These 1950s pinch waist tubes are rarely found, since they are so fine most are in private collections and stocks!