I've got a Dacmagic Dacmagic 100 and I found a problem about the heat and want to verify it. It generates some amount of heat when working and this is normal. But sometimes, I forget to shut off the power switch after turning the DAC to off (or standby), and overtimes, the DAC can still feel obvous warm when staying in off mode. Does that mean there is some problem with the power supply or is it normal? Thanks.