Hi Steve,
I just came across a pair of NOS  5881 output tubes. The 5881's are on the list of recommended output tubes for the MiniT and wanted to give them a listen for their sonic presentation. But,.....are the 5881's a direct plug in and safe alternative for the 6V6's or would they cause any undue stress to the 6X4 rectifier or any of the other tubes?
Figure I'd better ask so not to cause any stress on the amp .........

Hey thanks Rivieraranch for your response much appreciated. I am listening to the 5881 this weekend and they do sound quite nice; give a much fuller presentation producing deep bass while retaining the detail and good imaging. Did notice that the baseplate of amp does seem a bit warmer to hot versus when running 6v6’s.  So, are 6L6GC not suitable for the MiniTorii ? I did see that Steve did list a pair of GE double getter 6L6GC’s so I’m not sure about the GC’s for MiniT use. I know some guitar amps specifically warn the user not to use the GC version if the amp is rated only for 6L6G’s because may cause tube damage.

OK, Good to know then.....thanks for sharing your experience with these output tubes.