XLR or RCA?

The real benefit of using XLR cables is in the fact that it allows you to utilize fully differential equipment designs, which will lower the noise floor. That being said, just because you are using XLR cables does not mean that your equipment is a fully differential design, it could be a single ended design that simply has XLR inputs and/or outputs on the unit for flexibility. If the unit is not a fully differential design, you will not receive the benefits of running XLR cables.

Also, yes, to receive the benefits of running fully differential, you should run all the way from source through amplifier to maintain this 'advantage'. Any break in the chain, anywhere in the chain, and using XLR interconnects becomes rather pointless.

According to the McIntosh website, neither the C2300 nor MC275 are fully differential designs. The XLR inputs and outputs are simply cosmetic, therefore should hold no advantage.

This is one of the rare occasions when I must very respectfully disagree with my learned A'gon colleague and friend Jmcgrogan2, although the opinion he expresses is shared by many audiophiles.

Elegal 02-17-14
I then read that xlr cables only provide a real benefit if you are using balanced cables throughout your entire system, which I presume means from my turntable into my preamp. Is this true?

My answer is that it is not necessarily true. Regardless of whether the components in the system are internally balanced or not, and regardless of whether all of the interconnections in the system are balanced or not, a balanced interface between any given pair of components is inherently less susceptible to noise that may be introduced as a result of ground loop or other effects. And in referring to "noise" I am referring not just to noise that may be audible as such, but also to the possibility that noise that may be introduced at frequencies which are too high to be audible may have audible consequences, by "intermodulating" with signal within the components.

On the other hand, it is not uncommon for the XLR interface circuits of components that are not internally balanced to be sonically inferior to the RCA interface circuits of those components.

The bottom line, IMO: Which interface would be best to use in your particular case cannot be predicted with any certainty. Hopefully someone will chime in who has experience making that comparison with the same or similar McIntosh components, as other opinions stand a very good chance of not being applicable. IMO, of course :-)

Regards,
-- Al

I would like to add to what Al says above in that the XLR connector itself is much better than most of the RCA connectors. IMHO, better than even the locking RCAs. Another potential added benefit to using balanced cables.

Thank you MOFI; AL; and JMC. I feel like I should send you guys some LP's for your help

There is a minor benefit in using XLR even though the component is not internally balanced....the big benefit is when one does it right.