I have the OSIRIS: it is a unique animal that I would characterize as a refined AND muscular 56 lb. beast, that is a pure 2-channel thoroughbred leader without the ancillary add-ons crammed in.
This thing is a brick. It’s crafted from aluminum and . It cranks out 160W into 8 ohms, increasing to 250W into 4 ohms.
Each channel has its own dedicated custom-made toroid transformer and the quad of Sanken 200W output transistors per channel means this behemoth has no problems driving any kind of load.
It has a direct pass-through option for any HT enthusiasts.
https://audiofi.net/2012/08/rega-osiris-punching-heavy/