Zyx can be loaded or unloaded from 100 Ohm to 47 000 Ohm, the manufacturer recommend more than 100 Ohm and it’s up to the owner (depends on the phono stage).
Thread about cartridge loading getting hot.
The goal of the special
ZYX headamp (CPP-1) is unique load resistors made by ZYX of the same copper wire just like the cartridge coil (if you have copper coil). This is very interesting device, not like a typical headamp or SUT, completely different. My ZYX CPP-1 mk2 has input impedance 125 Ohm as i can see in the manual. I’ve been using not only ZYX cartridges with it (Airy III and Premium 4D) but many other cartridges with great results.