There’s some good advice already here so I’ll just add this. The comment about good transformers is key, and old iron can’t be beat. Go vintage, but get something with the power supply caps redone unless you can do it yourself. That’s easy with point to point wiring in vintage equipment. Use vintage tubes.
Don’t spend a lot. Start with an integrated to see if you like “the tube sound”. One of the best you could do here is a Scott 299C. It was my introduction to tubes and changed the way I heard music. I had a $$$ surround rig and after hearing the 299C it was game on.. But beware, tube amplifier collecting is addictive.
Move on to a good tube preamp and power amp. Here I like some of the newer preamps, but stay with vintage power. I have plenty of both but my favs are my Wright 6SN7 based preamp and Quad II power amps. The Wright has open architecture that makes for easy tube rolling, which you will become addicted to. KT66 power amps like the Quad II’s are a good choice, smooth and neutral. A lot of the Dynaco power amps that have been modded also fit the bill.
Going tube is a journey, deeper than the solid state road. Enjoy.