Do you mean X-A100 and X-A50 respectively?
If so, were you bi-amping the 704's speakers with the X-A100 and the Monoblocks?
Curious as to why you would have a set up with an integrated and pair of MB's, if not bi-amping.
Not really sure what you are trying to achieve. I would have thought the most obvious course of action would be to keep the integrated and replace the mono-blocks with something more modern.
Most modern mono blocs of similar spec to the X-A50 would have balanced inputs and I don't think that X-A100 has balanced outputs so you would probably need a pair of RCA/XLR adaptors. Loads of great mono-blocks to choose from. These both look like good value at the moment.
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However if you want to remove the MB's - perhaps to simplify your set up? - and go integrated only route the options you have listed are both good. You just need to decide what you like the sound of and how much you are prepared to spend. If I were you I think I would replace the MB's with modern ones and get a good pre-amp with balanced outputs instead of the integrated, but that is just my opinion. Not sure you will get much more help until you are clearer about what you are trying to achieve and what budget constraints you have. HTH.
