Another Sony understatement : great gear which didn't bother to really look like it and an unbeatable sound/price/durability ratio !
Sold in Japan under the same moniker but without the "SD" compatibility for 84.800¥, below the old ST-5000F (105.000¥, 1976).
For the price the ST-5950 goes for nowadays (SD or not), the bargain still stands. In spades.
Under the title of "Futuristic Peculiarities", a french '76/77 catalog says that "Dolby FM is already widespread in the USA and it is bound to happen in Europe as well, soon." ;-)
The little brother, ST-4950, in its non-SD version was also available as a black-face WEGA T-4710.
For even better FM sound, go for an ST-A6B or the ST-A7B masterpiece.