You will always loose sound quality with adapters no matter how good.I think you best bet is to look at an amp that does single ended well such as PASS etc.
RCA to XLR Adapter
I have a Herron pre amp that has only RCA outputs. I'm considering buying a pair of used Merrill Audio Veritas Monoblocks that only have XLR inputs. I found these
Cardas female RCA to male XLR adapters that would allow me to make the connection. Are there any downsides to using adapters such as these?