Another vote for Bel Canto Ref600M. I would steer clear of any UcD Hypex module build amp, especially if you plan to pair them with Ref10.
I have heard Mola Mola Kaluga’s and they are quite amazing. You should also consider Merrill’s Veritas mono’s.
I have heard Mola Mola Kaluga’s and they are quite amazing. You should also consider Merrill’s Veritas mono’s.