Longtime lurker First time Poster

so i have been around a while, but i have never had a reason to post. recently i have come into possession of a belari VPN 129 preamp and a music hall 2.1 turntable. i upgraded the cartridge to a grado gold, but i was wondering what other reasonably inexpensive upgrades i could make? can i use some different tubes? what makes one tube different from another? is there a next step in the phono preamp that i should read up on? i am really sick with the audiophile disease!