MC cartridges are not inherently balanced, in fact no cartridge be it MC or MM is inherently balanced.
Balance connection consist of + signal - signal and ground, I have never seen any cartridge that is made that way.
That is not what I have read. The signal is isolated from the cartridge chassis ground. But I am certainly no expert. Below is a quote from one source and a link from Pro-ject. I am not trying to contradict you, just trying to learn.
https://pro-jectusa.com/true-balanced-audio-faqs/""With the exception of some Moving Magnet (MM) and Moving Iron (MI) designs that ground one end of the coil, the signal from a phono cartridge is “balanced”. The differences are how that signal is dealt with by the phono preamp.
“Some” tonearms also ground one end of each signal coil.
One can test tonearm wiring fairly easily with a multi meter’s resistance setting. Remove the cartridge first, you don’t really want to apply the admittedly small DC voltage from the meter to the cartridges coil.
It is reasonably straight forward to change tone arm wiring (or tone arm cable wiring) to “balanced” if it isn’t.
All Moving Coil (MC) cartridges are “balanced”.