I don't know of a product from Wadia that wasn't first class. That doesn't mean it will be the best product for your system. I'm afraid you've asked a question that is all but impossible to answer. If the Cambridge and the Wadia have complimentary output/input connections, they will work together. That still doesn't suggest whether you should proceed with this combination.
Cambridge CD player covers a wide bit of territory and even with a specific product number we can't predict how a unit will sound. As a rule, Cambridge players are about good quality, involving music reproduction. You'd have to give a reason why you would want to change that basic approach before I could suggest whether you might be on the right or wrong track. If this is a case where you think you might buy something just because it's available, that's typically not the way to build a first rate system. So, why do you want to change DAC's? Can you audition this unit with a Cambridge player that you own?
I have owned Wadia and listened to several models by Wadia, but I must admit I have not listened to the 64.4 DAC. I also own a Cambridge (the 640 hard drive based unit that is the same as the 640 CDP but with a built-in hard drive). Wadia is an excellent company, one of the top 5 highest regarded digital product company's for audio and produces solid reliable equipment (any comments otherwise would be based on information from over a decade ago). The DAC section of the Cambridge is going to be middle of the road, nothing exceptional but nothing too offensive either. Though the new CDP 840 is supposed to have improved DACs based on what I have read. I bought my 640 unit with 100% intentions of running through a DAC, which in my opinion is required for this unit to sound its best (reach its potential so to speak).