Hi. I have just bought a Panasonic RF-2200. Does anyone recall what model of headphones would have been sold circa 1978, that might have been marketed to be used with this radio? I'm looking to buy a modern retro set of headphones made by Panasonic, but before I decide anything, I'd like to know, if possible, what the headphones were at the time the RF-2200 was made. Perhaps an old-timer can recall. Thanks.