I also have an Adcom 5503, which I used to drive three Magneplanar MG1.6 speakers. I changed to using CarverPro ZR1600 amps (digital, and rated at 600 wpc into 4 ohms) and I do believe that there was a significant improvement. But then, Maggies are known to respond well to high amp power.
The reason I was willing to try the ZR1600 was its very low cost (I paid $2520 for three of them) and favorable comment by others.
The Adcom is a perfectly respectable piece of equipment (although the brand is looked down upon by many audiophiles). No doubt it can be improved upon, but, how much, and at what cost? If money matters to you I would suggest that you demand a home trial with your speakers and associated equipment before laying down many kilobucks for a different amp. Only buy if YOU hear an improvement.
The reason I was willing to try the ZR1600 was its very low cost (I paid $2520 for three of them) and favorable comment by others.
The Adcom is a perfectly respectable piece of equipment (although the brand is looked down upon by many audiophiles). No doubt it can be improved upon, but, how much, and at what cost? If money matters to you I would suggest that you demand a home trial with your speakers and associated equipment before laying down many kilobucks for a different amp. Only buy if YOU hear an improvement.