LoL,
Correct J,...I was giving the generic answer without confusing nuances and yes, there are many nuances as you rightly pointed out.
I heard the 6 in Europe and the 7 in the US, so not side by side. I think the 6 I heard was tube tricked out, but will confirm later, but the 7 was stock, in terms of tube complement. The 6 was lovely and perhaps more RBCD capable at the moment, but I am all over the place with RBCD, Hirez and DSD.
As a standard,the 6 does NOT have DSD, but as the units are hand built, I think as a special it can be done. My pal will look into adding a DSD module to his 6.
J, have you yet gotten to try an RCA VT-99 in your Dac yet? if so, what was the outcome?