Transistor amps are more common in bass setups than among guitarists, and back when i played live a lot, i came across some transistor amps that had a really great, well-defined sound. But the high-end stuff often has at least a tube preamp, and then there's these refrigerator-sized all-tube Ampeg stacks that you see in a lot of professional setups. I usually play through a Mark Bass Vintage tube preamp, which is just the pedalboard version of one of their normal heads, missing only the power amp, comes complete with effects loop and a bunch of different outputs. I like that a lot, it sounds good, it's versatile and i can use the same setup for practicing at home through headphones and for playing DI when i get around to jamming in my friends' studio again once everybody's vaxxed. I think if i'd get into a band again where playing DI isn't a thing, i'd just get a seperate poweramp and use it with the preamp on my board, it's really convenient when you ignore that my pedalboard suitcase weighs as much as a small rhino now.