In decades gone by it seems several popular op amp types, e.g. TL074 and TL084 (there were probably others), were made with a silver paint topping on them, here is an example:
I've seen them called 'silver series', but extensive searching has not revealed what was 'special' about them to be packaged in this way. I suspect the only way to find out will be to find an old datasheet detailing what this packaging meant. Those in the photo have clearly had original markings painted-over by the silver, and then re-marked (are they selected for some parameter or other after having been packaged-up?).
In these days of counterfeits and blacktopping etc., it would be nice to know just exactly what the purpose of these were, so as to allay fears as to their provenance.
Anyone got any ideas, or better still, an old datasheet/databook detailing the significance?
Thanks, Tim
