Ancient_Hacker wrote:
I've never seen this happen in transistor radios, and I've played
hundreds of old ones. Is this problem limited to certain transistor
designs? Most US transistors went from alloy-junction type directly
to silicon planar, circa 1962.

I have heard that such phenomenon happens in old Philips AF116/AF117
transistors, commonly used in the sixties in the FM tuner.

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Met vriendelijke groet,

Maarten Bakker.