UCA202 INTERNALS: The UCA202 uses a highly integrated Burr Brown/TI PCM29xx CODEC chip. As mentioned earlier, they’re nearly $6 each in 2000 piece quantities. With most everything integrated into a single chip, it makes the implementation harder to screw up. The chip has a delta-sigma DAC, oversampling digital filter, and is rated for 93 dB of dynamic range and 0.005% THD+N. The PCM2902 Datasheet has more info.  A classic 4558 op-amp is the headphone amp and another pair of op-amps handle line in/out duties. The power supply looks to be reasonably well filtered.