“Philip Gruebele’s two USB-to-S/PDIF converter models can now operate with his very low noise PurePower module. That’s a rechargeable battery pack which keeps dirty USB power isolated from the twin clocks and S/PDIF output stage whilst USB still powers the ARM RISC processor and USB interface. With up to 15 hours of continuous play time, the PurePower auto-charges when sensing that the converter isn’t processing data. A display shows power and play time. Existing owners must return their D/D converters to have a new power connector fitted. New units can be ordered with our without the PurePower option. The upgrade is available for $399. Introductory bundle prices for a new Audiophilleo 1 or 2 plus PurePower are $1.399 or $999 respectively.”
You can read my review of the Audiophilleo USB to S/PDIF converter here.