Sony's most successful power amp (bar the pre-Esprit TA-N86B) and Sony's only unit sporting monster meters - the TA-N77ES was made to drive just about any loudspeaker available with no signs of stress. Many many many N77s are still in use today. Its only common flaw was fairly unstable meter bulbs - not the meters, just the bulbs.
Included in this powerhouse were most of Sony's technological staples : Super Legato Linear, Spontaneous Twin Drive power supply, Gibraltar chassis base and resin-cast power supply caps plus a triple push-pull of bipolar transistors which make music.
Unlike the TA-N80ES follower, only single-ended inputs were available ; the reservoir of caps seems to have seen several versions, as catalog images show the N77ES with either 2, 4 or... 6 main power caps. Only the TA-N80ES follower had its bank full with 6 caps while the production TA-N77ES all had four.
Whether N77ES or N80ES, specs are nearly identical.
However, even if not as complex as other components, in true Sony tradition, the TA-N77ES had several versions.
Here is an interesting comment from John, avid australian ES collector who, not only owns a pair of a Yamaha NS-1000 but also has a pair of xxx-rare Sony SS-G333ES speakers :
"The 110-240V multi version N77ES has some difference to the 120V version internally related to the turn on circuitry and overload circuitry :
the US N77 could not deliver the same power as the multivoltage units due to a two stage protector that actually reduced the power by switching in a lower supply rail when an overload was detected.
Not only that, there were problems with the relay contacts in the supply rails. The multivoltage unit is by far the best."
A true worldwide bestseller nevertheless but not in Japan : Sony never made an ES pre/power stereo combo available on its home market : so the TA-N77ES, like its preamp mate TA-E77ESD, was export only.
I have no idea where or by whom it was actually designed.