I've been searching and I haven't come across general information about small signal tube positive grid operation that would give me a ballpark idea about this specific tube. The 6S31B data sheets (here and here) have a +.5V grid plate curve drawn. I also see a nominal operating point is listed with a 0 volt grid bias. It seems like going positive on the grid of this tube is part of its design intention but I can't make out what kind of grid current it might draw since I recognize very little Russian.
In general, if there's a positive grid voltage plate curve drawn for a small signal tube, is it reasonable to assume that going positive on your input is alright provided the previous stage can provide the power?
In general, if there's a positive grid voltage plate curve drawn for a small signal tube, is it reasonable to assume that going positive on your input is alright provided the previous stage can provide the power?