I own a JD-100, that has only slight mods: chassis damping sheets and better tubes. Many people are suggesting that the Sylvania's are a great match for this player. I run the Sovtek's and am not looking for anything better. I have been listening to this player 6-8 hours a day. Incredibly warm, fluid, natural sound. If it helps, my system includes: Jolida 502B integrated tube amp, Soliloquy 5.3 floorstanders, Adire Rava sub, Zu Cable Wax single wire speaker cables, Signal Cable IC and PC's. I'm obsessed with upgrade possiblities, and still, the JD-100 is staying put.