Originally Posted by lh2705
i did however read somewhere that the volume can't be controlled when connected to an SGS3.
The volume can be controlled when connected to a SGS3.
I don't have a UD100, but an ODAC.
UD100, ODAC, AudioQuest DragonFly have the same ESS Sabre ES9023 chip.
The adjustable output level feature of the ESS Sabre ES9023 chip is not implemented in the UD100 or in the ODAC unlike in the AudioQuest DragonFly, which can be used as a USB DAC or as a USB DAC/amp (i.e. with adjustable output level control).
The DragonFly allows USB Human Interface Device volume control from the player software on the USB host (i.e. PC or Mac).
However without proper USB HID digital volume control, a player software can adjust the output level "by multiplying the each successive word in the original signal data stream by a coefficient that is less than one. For example, if the incoming signal is multiplied by a coefficient of 0.5, the output will be half of the original value. This corresponds with a volume reduction of 6 dB. In a binary system, a reduction of 6 dB is the same as shifting the signal towards the least significant bit by one bit", hence a theoretical loss of resolution.
About digital volume control: