For the last several days, every bit of my free time has been spent burrowing down the great tube rabbit hole. I made my mind up ten times, ten different ways. In the end, I didn't get any NOS gems, only new stuff. First off, the little guys: a jj 12au7 because I hear good things and I will use it. Also, three tung sol 12ax7 because it's been a while, too long, without. No Genalex gold today, maybe next time. Next up is the big boys. I went round and round and finally decided on the jj 5881. Compared to a 6l6gc, they can handle the high plate voltages while offering a reduced watt output. I got a matched quad to replace the 20+ year old jj 6l6gc in my 135w Twin Reverb. And, before I load those up in my TR, I'll be trying them out in the old Supro Thunderbolt that just got out of the shop. I hope this will help inform me as to whether to get a pair of NOS tung sol 5881, also known as the 6l6wgb (RCA, GE, Sylvania, etc.) for the Thunderbolt. Not that I really want to spend a bunch of money on two tubes, but if I like the results, I'll spring for an (A)NOS 6l6wgb matched pair.