Upgrade speakers or DAC

Speakers!

Speakers will always make the biggest different in sound quality, bar none.  The question is when does one stop ?

Always source you will be amazed that when you have a great source how much better your system will sound. The speakers can only produce what is feed to them.  We have used old box speakers KLH form the 70s and found that they disappear with a better source much to our surprise.

SPEAKERS Speakers are where the rubber meets the road

It's actually a toss-up. Upgrading your speakers will make the biggest difference in the sound of your system but you will not hear what they are capable of until you upgrade your source components. Conversely, upgrading your sources will make significant changes as well but to get the full benefits you will have to upgrade the speakers. This is why I always suggest that once your system is matched, leave it alone and enjoy the music. Otherwise be prepared for a trip down the rabbit hole.