Some people like black tea, some like green tea... so maybe Classic TEA and Modern TEA. But then where do we draw the line? Is early 80's Modern or Classic? I do not (yet) have any nixie or tube equipment (there's always tomorrow) which would definitely fall in to the Classic category. And then there's the Mr. Carlson level of Classic TEA....
What are you waiting for?!?
Get a search going for an HP 405 AR or CR, and you can tick both boxes off at once!
This isn't really something that I believe can be defined by hard and fast rules or dates, but in general I think I'd call 80s era stuff more classic than modern (perhaps 'modern classic'?). Modern to me is when you open the enclosure and it's mostly air inside, with a board that has one or two big million-footed ICs on it, and you have to wait while it boots up. Features could include LCD or OLED screens, 'soft' controls with multiple, context defined functions, that sort of thing.
Classic would have tubes and/or transistors with perhaps a few simple ICs, and I guess I'd call 'modern classic' stuff that's more IC based, and which may also have a microprocessor, but that still has a lot of individual supporting components too - something like the HP 3561A Dynamic Signal Analyzer comes to mind as a good example. Things introduced from the mid 70s on as a rough starting point, up till 1990ish I suppose, off the top of my head.
-Pat