Shawn, the JD9 II isn't going to limit your choice of cartridges. It has more options than most phono preamps and the design appears to be especially suited to low output moving coil cartridges. I've run a few LOMC cartridges through the JD9 and the preamp did well with each of them.
What you need to consider is why you want to change cartridges in the first place. You say you want better but aren't clear on what you don't like about your current setup. Is it the tonal balance? Too much or too little bass or treble? Does your system sound overly bright, or dull and muddy? Are you looking for more detail and resolution?
And have you tried making some changes in your room acoustics? You can do a lot to improve the sound by making simple changes in wall or floor coverings or speaker placement. Plus, until you try swapping out the tubes in your JD9 you won't really know what you're looking for. I found that certain tubes could tame what I considered a bright-sounding setup and make listening to the same cartridge and preamp very enjoyable.
I'd hold off on buying another cartridge until you get to know the JD9 (and the rest of your system) better by doing some critical listening to learn what you're looking for. Then you can search for a cartridge that complements your system.
Regards,
Tom
