Turns out that after looking at a gazillion other E188CC tubes on google and ebay, code VR2 means that these were part of a batch made in 1960, since any tube made later has a higher change code (actually, almost all the Heerlen-made E188CC you find have VR6 to VR9 codes and were made in the mid to late 60's, so much later). But what's even better is that tubes with the VR0 (first batch ever) or VR1 are the famous very early late 50's production with either a D-getter or a folded D-getter (= extreme prices); almost prototype-like tubes in a sense. So the VR2 tubes should essentially be the first batch of large O-getter E188CC tubes to have come out of Heerlen (give or take a few months). And as gibosi and I realized with the US Amperex 6922, the earlier the better, and those VR2 are pretty early!
This is good information to have. I have a single Heerlen-made Dario VR2 coming to me from France. (It is taking longer to get a tube from France than from the Ukraine! It was shipped on November 11! lol). Tube code: VR2 40H3. (And of course, since the Heerlen delta character is not readily available on most computer keyboards, many vendors use the number 4). I knew from the change code of 2 that it was early, that is, August, 1960, rather than 1970, and I would guess that your "PO" tubes are even earlier. I am hoping to have it next week and really looking forward to seeing how this tube compares to the US-made Amperex.
Edited by gibosi - 12/1/13 at 6:12am