Following the great factory fire of 1914 Edison released a new series of internal horn Amberola machines to play the new four minute cylinders. These were the Amberola 30, 50 and 75, the model designation referring to their original price in dollars.
The initial introduction of the most expensive model, the Amberola 75, occurred in July 1915, according to Frow's reference book The Edison Cylinder Phonograph Companion.
