Summary: This product worked as advertised for the first four months of light usage. Then I started to use the DAC for 8+ hours a day and sometimes just left it on. After four months, the unit now gets hot after a 5-6 hours of use, then produces a high pitched hum. This used to happen rarely in the first couple of months, now it is every other day. The only fix for this is to unplug the unit and let it cool down for half an hour.