Old Amps that can still Kick Butt

Not being a believer that time necessarily = progress, I would like to offer the following example of a sonic gem that has transcended time and can totally kick butt in a modern milieu:

The Robertson 4010. I got one of these about two years ago because it was in immaculate condition, the price was so low and I was inquisitive. I hooked it up and let it warm up for a couple of days. OMG this thing was in the super amp league: Transparency to die for, slam that you couldn‘t‘ believe for for a 50W amp.. Peter Moncrieffe wasn‘t wrong in his review of this amp: this thing is in the Sterreophile Class A component category hands down. Even after all these years.

What amps have you encountered that have defied time and can still kick butt today?

My newest amp is 21 years old this year: a Krell FBP 200c. Older is my Eagle 2A; my oldest at 46 years is my perfectly functioning SAE MkIV DM, which powers my secondary system (also with an Audio Research SP-9B preamp) that has a played several times each week. 
Loooong time ago, my friend (RIP, Asit)
worked for roadrunner records, went to the recording studio here near him in Chicago, Suffocation, Deicide, all the 80’s roadrunner bands recorded there!,!!  Was awesome! Met Suffocation,Deicide, King Diamond, and so many other bands in the studio. 
they had the B&W 80? In the studio, and ran everything with Threshold amps.

   They are still relevant and amazing!!