UltraAnalog 20 bit vs. Burr Brown 24 bit

It may not have the top end shimmer or bottom end slam...but some of the CD players or DACs that I have heard with the old UltraAnalog 20 bit DACs sound more like music than some of the more recent chips....any other thoughts out there?
It depends which of the Burr-Brown DACs you are referring to. They (BB) offer a number of delta-sigma devices that are capable of processing 24-bit sample sizes. As most of these devices are very to extremely inexpensive, there performance is not particularly impressive. Burr-Brown also fabricates one of the finest 24-bit devices ever conceived. The PCM1704 is a device that handily exceeds the performance of the UA modules in every area of interest. Keep in mind that the difference in manufacturing costs between the entry level and state-of-the-art Burr-Brown devices are at least 50:1. Not all things that are 24-bit capable are necessarily high performance. Kevin Halverson
The continously advances in semiconductor fabricating process will produce better and better data conversion products, in this case the DACs inside your audio equipments. The differences could be the grading quality of the BB DAC vs. the Ultra Analog DAC, the preceeding digital filter, error correction, dithering or noise shaping stages and no less important the lowpass analog filter stage just before output. So you may have to dig deeper into the design of each piece of equipment to figure out why the discrepancies. Cheers,