I'd suggest you try a preamp that uses 6SN7 tubes. It probably will be a more full sound than with a 12AX7 type -generally-, many exceptions. There are still many available and affordable NOS tubes to have fun "rolling". The 6SN7 are just a great tube "family".
Your speaker's efficiency will dictate your power requirements but KT88's/6550's are powerful enough not to limit you too much, allow for tube switching fun and decent bass. (Quicksilver amps are a good value choice here.) I find EL-34's to tend to sound thin in inexpensive amps. Do try EL-84 based amps if you have more efficient speakers. They'll surprise you!
Your speaker's efficiency will dictate your power requirements but KT88's/6550's are powerful enough not to limit you too much, allow for tube switching fun and decent bass. (Quicksilver amps are a good value choice here.) I find EL-34's to tend to sound thin in inexpensive amps. Do try EL-84 based amps if you have more efficient speakers. They'll surprise you!