Yeah, pretty much apples to fish. The big amp seemed less detailed, more electronic sounding, much more colored....but this is a very clean and detailed "sophisticated" tube amp. I can imagine some mediocre vintage tube amps sounding less detailed and more colored than the 500W Altec.

The thing that scared me is that the Altec sounded like it could blow the cones right out of the JBL bookshelf speakers on a loud transient, as it most certainly could if I cranked it up.

I have always run Altec horns with tubes for domestic use but there is a group of Altec fans in Japan who love to use big Altec SS amps on VOTs and similar. I saw a Japanese blog where a guy carefully restored a set of 210 cabs then bought a set of huge Altec amps that had stickers on them from the motor speedway they were surplussed out of! Dang, that must be loud!