Sony ST-5000
(may 1967 - 1968)
Sony ST-5000F
(february 1969 - 1976)

Part of Sony's first foray into HIGH-Fidelity and the last original ES unit to appear after the TA-1120, TA-4300, TTS-3000 etc.
Yes : ES dates as far back as 1965 !

The original ST-5000 was quickly replaced by the 5000F (F for FET), the latter vanishing also quickly in favor of more affordable units with less drastic bulid quality such as the ST-5130.

Just as for the TA-2000F, an xxxxxx-rare black version of the 5000F has resurfaced in Germany ; since both units appeared in the same country, I suspect these black versions to have been "distributor" or even "shop" custom-made. That said, a black-faced STR-6060F has been discovered in Japan (STR-6000) so... maybe... perhaps...?

Like a few other 1960s units, the 5000F remained available in Japan far longer than elsewhere, even remaining more expensive than the excellent ST-5950 topper in 1976 !

A very informative review of both models is available at the Tuner Information Center.