vintage versus modern speakers

If I recall correctly, Nelson did not design any SAE stuff. I believe that Jim Bonjiorno did that basic design on your amp, although I know that Ed Miller put his hands in several amps of that era also.
Since I've chimed in... My 2 cents on the speaker discussion.
Basic design parameters hasn't changed. There were some nice speakers put out in the late 70's & 80's... Jon Dalquist had a few, Infinity, DCM was ok, recently I have been modding an Altec A7, they have turned out quite nice. What has changed is, Material technology... we now have Kevlar, carbon fiber, magnesium, aluminum, ceramic, pulp wood fiber cones & yada yada yada... This has changed along with a much improved manufacturing process. We used to have measure 50 drivers to match up a half dozen to tight tolerances. Today, they come off the line within 5% or better tolerances... Combine that with better caps & resisters along with compensation circuitry not typically used back then and normally, Yes, today, overall speakers are better, but there is no doubt that there were satisfying speakers of yesteryear that if found in good shape could offer some enjoyment.

Rockanroller, here is my feeble minded attempt to explain voltage paradigm for those that share my huge intellect.
A Voltage paradigm amplifier is one that is capable of maintaining its voltage output at any given impedance, say from 2 to 16 ohms.... If you give an 8 ohm load a consistent voltage, the amplifier will give you its capable power output, If the Voltage is maintained for 4 ohms, the power output will double, if Voltage is still maintained at 2 ohms, power will double again.
In a power Paradigm amplifier, the amplifier is designed to give you a constant power at any given impedance, typically 4 to 16 ohms.
I'm sure someone out there can straighten out any imperfections in that explanation, but it will put you in the league of a correct answer.