Here is a good way to identify bogus counterfeit output TO3 transistors.
The key is to look at the bottom as much as the top and thickness.
Most if not all vintage transistors had fairly small insulators holding the 2 pins in place. They were usually blue in color but I have seen other colors.
New style transistors are always made with large Blue, and sometimes Green insulators. (probably 3X the diameter of the original vintage ones)
New style Motorola (On-Semi) use the large insulators, and can be genuine or counterfeit, all depending on the source in my opinion because they are cloned by many so you need to be careful.
The single transistor in the bottom row is an on-semi MJ21194
The 3 transistors in the top row are used Genuine Vintage transistors. They always have a smaller set of insulators
The top left is a 2SB600 made by NEC and used in the pioneer SX-1250. Its thick. The Sanken 2SC1116 and 2SC1116A look like this.
The top middle and right are Toshiba 2SB554, and 2SB557 used in various pioneers. Genuine Toshiba outputs always have that strange hourglass design imprinted on the bottom.
The below picture is a genuine original 2SC1116 Sanken transistor used in the Sansui AU717 I am working on. Notice it has a thick base, and if I had removed it you would have saw small insulators.
If you get a vintage transistor with large insulators, it is probably counterfeit. The only old vintage transistors with large insulators that I know of were usually high voltage ones like the Matsushita 2SD350 (1500v B-E 700v C-E)
