[mark_in_manc]

I have used Russian equivalents to 6L6 in a pair of Quad IIs for some time - using roman characters they're numbered 6p3s. I found them to work fine, though I have no measurements to back that up. I too have had no trouble with east-european vendors, though I know folks who have not been so fortunate. I have some Russian ECC83 near equivalents (heaters wired differently, I think) and EL84 too, for a guitar amplifier project which is somewhat stalled.