One thing that may be a problem is the age of your speakers. If the voice coils have been warm in the past from loud volume, they may fail quicker than a new pair. The glue in them could be getting weak just from age also.
On the tube amp clipping issue, tube amps do seem to give a better warning with audible distortion more noticeable quicker than SS amps in my past experience. I have never blown a speaker with a tube amp yet. I use a fuse when running low powered SS amps, because they do catch you off guard quicker than tubes do with distortion in my past experience. Yes I have blown speakers with low powered SS amps, that's the reason for the fuse with them. I don't use a fuse with tube amps. If it would blow(with tube amp), it could cause the output transformers to blow, for not having a speaker load.
In the end, anything you hear that sounds wrong, back the volume down to be safe, and save your equipment. And I also agree with the volume position not meaning much, since it can vary so much in some types of gear, and/or matching of gear.
On the tube amp clipping issue, tube amps do seem to give a better warning with audible distortion more noticeable quicker than SS amps in my past experience. I have never blown a speaker with a tube amp yet. I use a fuse when running low powered SS amps, because they do catch you off guard quicker than tubes do with distortion in my past experience. Yes I have blown speakers with low powered SS amps, that's the reason for the fuse with them. I don't use a fuse with tube amps. If it would blow(with tube amp), it could cause the output transformers to blow, for not having a speaker load.
In the end, anything you hear that sounds wrong, back the volume down to be safe, and save your equipment. And I also agree with the volume position not meaning much, since it can vary so much in some types of gear, and/or matching of gear.