There aren't vintage tube preamps that support the standard, as they are all single-ended. The oldest tube preamps that support the standard were made by us- we made the first balanced line preamps back in 1989. IIRC Rowland was the second to make such, but to my knowledge didn't support the standard. One easy way to tell is whether RCA outputs are provided in addition to the XLR outputs; if they are then the standard likely isn't supported. This is because RCAs do reference ground, where as an XLR connection should not- they are inherently incompatible.
As best I can tell the Pass Labs preamps don't support the standard.
Now you don't *have* to have a preamp that supports the standard; if the preamp doesn't it can still sound just fine, you just don't get all the benefits that are supposed to come with balanced line- lack of ground loops, immunity to interconnect cable artifacts and the ability to run really long cables (although the benefit is there even if the connection is only 1 foot long).
As best I can tell the Pass Labs preamps don't support the standard.
Now you don't *have* to have a preamp that supports the standard; if the preamp doesn't it can still sound just fine, you just don't get all the benefits that are supposed to come with balanced line- lack of ground loops, immunity to interconnect cable artifacts and the ability to run really long cables (although the benefit is there even if the connection is only 1 foot long).