EXACTLY!You really do need to try out other amps and see if they do what you want. I had an Ampeg SVT, moved to an Aguilar DB750, and now play a Mesa D800. They all sound great in their own way, and I’ve been satisfied with each of them. But what I miss most about the SVT is the glow and smell of the tubes. Weird, right? The sound is also great, but other amps sound just as good (albeit different) for literally 1/10th of the weight. The SVT is just impractical for most folks. I know the 3PRO is a different consideration, but the point still stands that you can likely find something you enjoy just as much but in a much more portable package.
I'm using a Mesa D800+ now, as my "usual" amp, but I sometime switch to the Quilter to change it up. They both sound great--- but differently so.
ALL amps can be EQ'd to put out a nice bass tone, but if the OP wants an amp that sounds exactly like an Ampeg SVT, there will be disappointments.
I think the sudden change from a 40 lb head to a 3 or 5 lb head will make up for a difference in tone anyway. It's nice to just throw a small, light head onto the front seat of the car when loading, and carry it with one hand across a lawn or car park when loading-in to a gig. I'll never go back to tubes, even if I got an SVT for free. That one, single sound is not worth the weight, and, as I have said in other posts, that Mesa is a tone MONSTER. I hate that it has spoiled me
on amps.