Your RSP-1068 pre/pro, RCD-1072 CD player, RB-1090 amp will drive the OB1s but I am not sure what you are trying to achieve.
In the stereo context, if you want to do better and you have the opportunity to try out some Bryston gear then go for it. I would recommend the BP26DA pre/DAC and 4BSST amp...use your 1072 as the transport and the DAC of the BP26. I am currently using Rotel RCD991 as transport, and Bryston BP25DA and 4BSST. I am very pleased with the clean, smooth, natural delivery I get in combi with the OB1s, which btw I found sounded even better once run-in. (As an aside I was interested that the left and right channels of the 4BSST were rated at 340 and 341 Watts respectively when tested in the Bryston factory, well above the stated 300W/ch.)
Your Rotel kit indicates a surround system in which case you might prefer the SP 1.7 pre/pro instead of the 2-channel BP26. I note that the SP 2 will soon be coming out. U can use the DAC of the SP instead of the Rotel to convert to analogue. What speakers would you use for the rest of your system?
As I say it depends on what you are tying to do. U might be happy with the Rotels driving the OB1s in a surround system, but if you plan to do serious/critical 2-ch listening, and budget permitting you might want to upgrade…still no harm in trying out some Bryston equipment if you have the opportunity!
R