The new tube is in and everything is working out great so far. The hiss is reduced although not gone (to be expected from tubes anyway) and the amp hasn't pitched a fit. No critical listening done yet though to compare the new tube to the old as last night's practice was kind of nuts with an extra guitarist, a drum machine, and a keyboard along with the regular band. Translation, it was loud as hell. Hopefully next practice will be a bit more subdued and I can get some critical listening done with the new tube sound.
John