McIntosh C52 to C53?

Another vote for separate DAC and leave everything else as is until you’re ready to step up to Aurender N150 or N200. I see DA2 upgrade in C53 as sheer convenience and not a day and night SQ upgrade. 

I had an Aurender A10 with the built in DAC and it was not as good as the built in DAC in my Mac C2700 ( DAC2 board) in my opinion anyway. The Aurender DAC was dry and rather boring sounding, the only thing I found it exceled at was it had a very low noise floor. The MAC DAC 2 board is really good for the money, but most DAC's above $2500 will out perform it. You can put a DAC2 board in your current C53 I believe. The HDMI ARC connection is great if you have a TV in the same room so that may be a factor. 

That said I got a Chord TT2 to try and it blew the DAC2 board away in all regards, I now have a Chord Dave i got used and its even better.

So a DAC is probably the best way to go IMO. 

As others have said, get a good dac. My C2500 has the DA1 dac and I prefer not to use it. It is based on the ESS chip which I am not fond of. I find it too forward sounding. Suppose you bought the C53 and a better dac comes In a newer Mac preamp. You would be constantly buying preamps with the latest and greatest.

Many thanks for everyones advise, all good. The one thing about the C53 is the DA2 DAC, it comes with, is actually replaceable. So when the DA3 comes out, $1,000 gets you an upgraded DAC.

@mgattmch 

I have the DA2 in my C2700 and also have a $19K retail outboard DAC. You will need to spend $5K on an outboard DAC to significantly better the DA2. My outboard DAC is better all around (actually stunning); however, which DAC do you think puts more of a smile on my face when I listen? Believe it or not, it's the DA2. Solely because of the performance that it provides versus the small cost of entry.