I don't think an Ampeg SVT (though I own and play one) is the be- and end-all of bassdom.
Amen brother! I loathe SVTs. I'm forced to use them at rehearsal studios, and cannot get a decent sound out of them to save my life. And I have no problems getting amps to sound good.
They just have awful EQ stacks. There's a big hump around 250Hz that you can't get rid of, and the low end is intentionally rolled off. The mids sound boxy.
My first good amp was a mid 60s B-15n. Wasn't loud enough to play over a rock drummer though. Wish I still had it, but it was stolen. My first good big amp was a Peavey "Bass".
(me and the Peavey in 1977)
Personally I have a Mesa 400+, which is a
very nice sounding tube amp. But it weighs a ton. So lately I have been using the head from a Trace Elliot BLX SMC combo. When I need some extra warmth, or tube drive, I use a TubeWorks Blue Tube, which has a 12AU7 in place of the stock 12AX7. That combination through my Mesa/Eden 4X10 cab is just wonderful.
I've removed the head from Trace since.
What I expect from an amp is to hear my bass the way it sounds DI'd into a board, with a little extra girth.