I recently acquired a used Alembic F-1X, and when I took the cover off to see what tube it had in it, I discovered that the metal "cannister" around the tube had been soldered in place. I had expected it to be of the "push in and twist to remove" variety. Can someone else with an F-1X tell me if mine is unique in this regard? If not, do you guys have to desolder and resolder the metal cannister every time you swap tubes? Thanks, Tom.