To share some of my experience with the AR2ax, having restored at least 4 pairs of these speakers, I can say that the best I’ve heard them play was with tube power. I use a Scott 222c (22 watts/channel) and also tried with a Dynaco ST70. Both with great sounding results.
What I can also say is that when I have A/B’d with AR3a’s, when using solid state power, the 2ax pairs usually sounded lifeless compared to the AR3a, a bold statement but just stating from my experiences.
On the other hand, the 2ax’s sound great and lively when AB’d with the AR3a’s using the Scott or Dynaco. The Scott wasnt a match for the AR3a’s, but the Dynaco linked up pretty well with both speakers. Both speakers were produce their best attributes, and neither outshined the other.
Final disclosure, I never have owned your receiver, nor any Marantz receivers, but my solid state choices (kenwood super eleven at 125 watts per channel and Soundcraftsmen MA 5002 at 250 watts per channel) neither sounded exceptionally well with the AR2ax, but both can sound good with the AR3a’s.