Martyw -
I've owned a JoLida 502B since 2001. I assume at least some of what I did will benefit your 302. Absolutely - upgrading the stock tubes is a place to start. I went to various KT88s in place of the Sovtek 6550s. Not sure what the 302B comes with stock. Talk to the folk at the TubeStore to get some ideas. I also upgraded the power cord and put in a HiFi Tuning Fuse. All these changes made a positive difference. My system is posted under Budget-minded so you will find additional details there. I recommend trying some of Herbie's AudioLab "Tenderfeet" underneath your amp. I found placement on a cutting board and better isolation seemed to tighten up the bass. Response Audio is another modder/upgrader to consider. Hope this helps.
I've owned a JoLida 502B since 2001. I assume at least some of what I did will benefit your 302. Absolutely - upgrading the stock tubes is a place to start. I went to various KT88s in place of the Sovtek 6550s. Not sure what the 302B comes with stock. Talk to the folk at the TubeStore to get some ideas. I also upgraded the power cord and put in a HiFi Tuning Fuse. All these changes made a positive difference. My system is posted under Budget-minded so you will find additional details there. I recommend trying some of Herbie's AudioLab "Tenderfeet" underneath your amp. I found placement on a cutting board and better isolation seemed to tighten up the bass. Response Audio is another modder/upgrader to consider. Hope this helps.