Dover’s advise is usually spot on, but in this case I believe he’s a little too stern. Many folks here seem to believe that the new stuff is always better. Obviously technological progress does exist, but in the case of turntables, tonearms and cartridges this is much exaggerated. I’ve owned pretty high level modern turntables and tonearms, but have come to prefer the old school Japanese analog devices from the ’80’s and ’90’s. I use old and new cartridges side by side and there’s no fundamental performance jump with the newer stuff. There are incremental improvements as more advanced manufacturing techniques and new materials have become available. But more often than not it’s just changing tastes, like the rather loud ’extreme detail retrieval’ crowd which still dominates the audio scene.
In short I see no reason why the MA-505 would fail to deliver a satisfying performance from ZYX cartridges, provided they are a good match in terms of effective mass. Nakatsuka’s designs are fairly traditional Japanese cartridges with a medium compliance, so I don’t see any reason to be disturbed or confused.