There are very(!) few tube amps that can adequately drive the 1 Ohm Apogees, though I can't imagine why anyone would want to, when ss is so obviously a better choice in this application.
Big Krells were the order of the day in the day. High current Classe' were also used when high volume levels weren't required. There have been reports of successful use of the newer Class D switching amps being used with Apogees, the H20's in particular seem to popular with some Apogee users.
I believe Magneplanar successfully sued over ribbon patent infringement, and that the patent might have recently expired, and that a new company is refurbishing and producing new (and improved?) Apogee like models.
Big Krells were the order of the day in the day. High current Classe' were also used when high volume levels weren't required. There have been reports of successful use of the newer Class D switching amps being used with Apogees, the H20's in particular seem to popular with some Apogee users.
I believe Magneplanar successfully sued over ribbon patent infringement, and that the patent might have recently expired, and that a new company is refurbishing and producing new (and improved?) Apogee like models.