20 Year Old Amplifiers compared to 2017

I imagine that Nelson underclocks the First Watt amps to prevent them from competing with Pass Labs. 

My Julius Futterman OTL3s are circa early 1980s. I recently had them converted from pentode to triode, and replaced all the caps with Jensen foil oil caps. They were tuned to my Altec 694Cs and to my room. 

I cannot imagine anything sounding significantly better for the money.

Good thread. I have an old Proceed Amp5 in need of TLC sitting around, that I've been debating back and forth about investing in a rebuild. It functions, but it's not working at its potential. Anyone have any thoughts?

I would think, that when comparing an older amplifier to newer designs, isn't it also essential to be certain that it still functions optimally? Maybe that's a dopey statement, but after 20 or more years, it's easy to neglect it and forget it might need refreshing.
In the case of my amp, it needs a good refurbishing, so I wouldn't dare compare it yet to anything. 

Kosst,
My F5 at the moment is being worked on very capable DIY'er, who, based discussions he has had with Nelson Pass, is doing some the upgrades you describe above.  It difficult to imagine the F5 improving, but it is logical thatat it will do so with the improvements you describe.  
Finally, there are lots of facts and opinions stated in the realm of audio blogs, but yours I consistently find the most logical and informed.  Thanks for sharing your information.  Whitestix