ddHiFi's 4.4mm balanced DAC dongles have gone through three generations: TC44B, TC44C, and TC44Pro.) They have slightly tweaked the TC44Pro with this latest version which improves the sound quality.
The previous CS43131 version of the TC44Pro featured a digital output connector and double-sided soldering points reserved on the motherboard. This new CS43198 revision has been simplified, particularly in the line optimization within the power supply circuit. It also features newer Cirrus Logic CS43198 DAC chips.
The CS43198 and CS43131 are otherwise identical in specs, but the more expensive CS43198 does sound a bit better.
The back of the TC44Pro is covered with a special 1800D carbon fibre panel. This flexible and lightweight carbon material has a low coefficient of thermal expansion and high thermal conductivity, effectively protecting the internal PCB board.
The TC44Pro features an integrally formed aluminum alloy shell, and the wavy surface reflects the delicacy of the new PRO-series titanium color.
It also comes with a leather lanyard that's not only a good decoration, but also allows you to easily carry the device and avoid losing it.
The TC44Pro's helpful indicator light keeps you alert of your current track's output quality and type: