I'll nominate my trusty Luxman L-5 which was purchased in the 70s. I am still using it 30 years later to drive my surround sound speakers on SACD. Sounds amazingly good and seems to be missing that 70s SS sound (which is why I bought it in the first place).
http://audio-database.com/LUXMANALPINE-LUXMAN/amp/l-5-e.html
http://audio-database.com/LUXMANALPINE-LUXMAN/amp/l-5-e.html