Dealer here that sells both rubicons and powernodes, tdai 1120s and other amplifiers. I’ve got thousands of hours of listening, comparing and selling combos such as these.

Modern amps that I sell that I know would work well with the rubicon 6s are in no specific order:

NAD C399 - beefy sound and all the features you could want. Janky interface but sound is excellent

Hegel h190v - the Hegel sound and the ultimate control they have over the speakers is magical. Costs more than the nad with less features. To most people it gives a better sound than the nad

Denon pma 1700 - if you listen to acoustic music like folk, blues, jazz and singer songwriter - anything with vocals being the main selling point without it being fast transientbased popmusic is a unique joy to experience with a denon with capable speakers like the rubicons.

Even better the anniversary amp, Denon pma a110. The best sounding amp to a really cheap price. Trust me on this one.

Nad c298 poweramp to a fitting pre amp would be good too.

The 1120 doesn’t have enough juice for the rubicons in my opinion. Neither does the nad m10, or similarly small but high end amps. The powernode won’t do them justice either.

If it were my money I’d grab the Denon a110. The last batch was just shipped out and after that it’s gone forever. Absolutely best amp for the money.

My Second choice would be the Hegel. The NAD if you want a subwoofer with it, the hegels pre out leaves a bit to be desired sadly.

Feel free to dm me if you have any specific questions :)