Nice sound!I have the same speakers in original diatone cabinets as they came from an console stereo i got from japan surplus auction in my country. I was about to sell it but when i tested it i was surprised with good sound! I was curious i opened up the box and found these drivers in mint condition. What happened next was i sold all my other speakers😁
I am happy to provide what i think should be nearly close figures for the dimension of the port. i measured with a ruler at hand the port section of the speaker box ( i happened to own and enjoy the use of the Diatone 610 in the maker- original box ) to determine the same. It is as follows: The port is;: Width 9.5 cm Hight 47.5 These numbers are measurement by sight and should not be considered exacting but hopefully usable to give a rough idea. It however seems interesting if it can be assumed that these numbers are somewhat correlated: there are two circles 47.5mm in diameter as you look and see the port. For your information the speaker box is Hight 53cm, Width 29 cm and Depth 25cm. The thickness of the board is roughly 14mm. Again these numbers are all measured by a very very elderly person with blurred eyes and shaking hands (laughter) but I hope they can be used to give a general idea.
They are mercury vapor rectifiers, probably 866A. Once they warm up, they have mercury in the tube that vaporizes and creates the blue glow. They are excellent rectifiers with very low voltage drop, but you wouldn't want one to break in your room if you wanted to continue living in your house in the short term. :)
