can i use a MM or a MC with a jolida jd-9?
do i even need to use a jolida jd-9 with a mcintoch c-30?
The Jolida can be set to accept either MM or MC. The C30 has a moving magnet phono stage. If you're going to use a moving magnet cartridge and like the sound of the C30's phono stage better than the Jolida, or if you just like the convenience of not having an extra box in the system, then you don't need the JD9.
Never having been a VPI or SME owner, I don't have a recommendation for you in terms of cartridge choice. In general, I've preferred moving magnets to moving coils and tend to stick to the cheaper end. At present, I'm using a $39 Audio Technica CN5625AL on my Linn LP12/Ittok rig, and am getting lively, engaging sound. The .7 mil conical tip is tracking at 2.25 grams and deals nicely with all my records, including some rather beat-up, bargain-bin albums. I've also liked the Shure M97xE mentioned above; its stabilizer brush really helps handle warped records, and the slightly shelved down upper frequencies make for pleasant long-term listening, never bright or fatiguing.
