I recently performed a review of Schiit Fulla DAC and Headphone amplifier. This is a follow teardown of the unit.Let's start with top down view of the unit:Starting on the right side we see the typical USB controller (Cmedia CM6631A) driving an AKM AK4490EQ DAC. An external flash IC holds the firmware for the device.Here is the Cmedia CM6631A top level features:And AK4490EQ:The output of the DAC goes to a pair of TI LMH6643MA amplifiers which output 75 milliamps:Notice the short circuit protection. From what I recall, shorts caused the unit to shut down though, requiring plugging and unplugging the USB cable. Regardless you should be able to plug and unplug the headphone without worrying about damaging the output stage.Since the distortion products were very different in each channel, I zoomed in to see if there were any part disparities between the two channels:I could not spot any. You are welcome to scrutinize it more and see if you can find it.Looking at the back side of the PC Board we find:Typical poor soldering job from Schiit.Solder splatter is clearly visible. Imagine these getting loose and shorting out the pins on the surface mount ICs. Their pin pitch is extremely small and these balls could easily cause a short.More here:The red solder mask keeps those from making an electrical connection. But also allows them to easily come loose causing potential shorts. It would take 2 seconds to blow or brush them off.The Schiit Fulla DAC and headphone amplifier has a simple architecture allowing its low cost of manufacturing. The most glaring problem with it is the horrible hand soldering job of through hole components, creating potential for shorts. This is like a restaurant that doesn't use soap to wash its dishes. You may not get sick from eating there but it sure is wrong. This is something you do not see even from low cost manufacturer.