As an ExaSound E32 owner myself (and coming from the E12), I've had a lot of success running the DACs from a 12v SLA battery, with an iFi DC iPurifier in line before the E32.
Curious as to what USB cable (if that's the input you're using) is working best for you. I am enjoying the Verastarr Nemesis USB cable the best so far, as it really shines with its natural and organic qualities and big soundstage, while still providing all the detail I need.