The weak link is your source. There are various options as mentioned CDP, DAC, build your own server which will sound better than the MAC, etc. Best option is a really good DAC IMO this will give you the biggest improvement. You really don't describe what you are searching for so it is hard to know what to advise you on. It is best to mention what music you listen to and where is lacks what you would like to change.
Happy Listening.
Happy Listening.