Strange you have listening fatigue with this set up. I don't see any components that stick out as a problem, although I am not all that familiar with the B&W speakers.
The Cardas wire is warm and low distortion, the Sony 777 Is supposed to be very good and I know for certain the Manley is good.
Given no other info, you might try a tube DAC with your Sony. I am trying the new Scott Nixon DAC and its tons smoother and more organic sounding than the analog output jacks from my Sony ES.
I guess you've tried the system with the Monster power conditioner removed?
I don't like that conditioner, but it can be a benefit if your power is in bad enough shape.
The Cardas wire is warm and low distortion, the Sony 777 Is supposed to be very good and I know for certain the Manley is good.
Given no other info, you might try a tube DAC with your Sony. I am trying the new Scott Nixon DAC and its tons smoother and more organic sounding than the analog output jacks from my Sony ES.
I guess you've tried the system with the Monster power conditioner removed?
I don't like that conditioner, but it can be a benefit if your power is in bad enough shape.