I actually have the same Jolida amp and the Kavent S33 preamp like the wolf man has. The Jolida 502P has matches up really well with the Kavent S33 preamp as well as a vintage Accuphase C200 preamp I have in my main system. Both are solid state. I did try the Jolida with a budget tube preamp. It was a Grant Fidelity DAC-09 that had a tube output and a volume control. The sound was somewhat impacted by the DAC-09. Depending on the tubes I used in the DAC-09 I got a slight bump in the mid-range. With getting a tube preamp and/or DAC the tube rolling combinations would get maddening.
I say keep things as is if you are find the combination enjoyable. If it isn't broke try not to fix it. Tweaking can be a money losing effort for you.
I say keep things as is if you are find the combination enjoyable. If it isn't broke try not to fix it. Tweaking can be a money losing effort for you.