understanding phono cartridges


so as i'm new to the analog game, i dont fully understand what makes a cartridge a good cartridge. and as such, i would like to understand better, so i can make a good decision when i buy the cart for my jvc a-l31. i dont have a whole lot of money to spend, and as it seems the tonearm on this deck is a low mass guy (i make this assumption based on the fact that its a thinner arm) i know heavier carts are out. so im looking at mm cartridges basically. any insight into what really matters in a cartridge, and suggestions that would work for me would be fantastic and greatly appreciated!
128x128chuckelator
yeah, 60 bucks on ebay brand new...but that will work well on a thinner arm like the one on my jvc?
I used an M97 on a Grace 707 arm, which is pretty low mass. Its a good all-rounder for a starter setup. Sounded very nice.
Audio Technica AT-91, at about 20+ to 30 bucks, its almost free. Anyone listened to it before?
I have a M97 that I use on my Technics table with very good results, a fine sounding cart that should make you very happy esp for $60, which I paid on ebay.
Yes I have the AT-91 and I use it when I am checking out older records that have a scratch or 2. It is almost unbelievable considering its price. I just added a new stylus for $15- and it will get you 90% of the music/sound of the M97. Of course being an addict I am more than willing to pay for the last 10%. Isn't this hobby all about paying exponentially for small incremental advances?