The SE difference is greater, the DP-X1A sound floor is noticeably lower and it sounds more open in the lower mids (the DP-X1 is a touch congested, in comparison). Running balanced the two are more similar and you'd need to compare them back-to-back to really tell a difference. However, the same differences that are shown in SE mode are also evident in balanced, They're just less pronounced. IMO, if you're going to run balanced most of the time, I'd just keep the DP-X1 if you already have one (or get one if you can find one on the cheap, and it doesn't have the port issues), but if SE performance is your primary concern the DP-X1A is a worthy upgrade. I do think the DP-X1A is the best dual Sabre implementation you can find on a DAP, and if you really like the latest Sabre DACs, like I do, this could very well be your jam. Just make sure to keep an external battery on-hand, as these players don't have the largest internal batteries.