Going pro. As per Mark Mallinson, the following four points distinguish the new ESS9028 Pro from its un-Pro predecessor. "1/ Quantizer improvement via additional dither. This 'scrambles' any artifacts the quantizer may add. These artifacts are very low indeed (somewhere below 130dB) but experience shows that perceived sound is better when the artifacts are not related to the sound signal being processed. Adding dither causes the human hearing process to 'de-correlate' the artifacts from the sound. We believe this is exactly like the vision system. At right are two pictures with exactly the same noise. In fact the picture on the right has more noise but it looks better. The eye/brain fills in the differences and it looks better.  In just the same way the SabrePRO moves the imperfection in the sound and 'blurs' them out so it sounds better.
"2/ The Sabre Pro loop improves the dynamics. In fact the error is about the same but we learnt that the hearing process will render a faster edge (even with an error) as sounding better than a slower edge. The left graph shows the difference.

"3/ This one is a bit complex but a long-standing overlooked potential improvement. It's complex mathematically but relates to 'mapping' the digital signals to analog elements on the chip. The improvement can be seen on lab instrumentation. Both Sabre and Sabre Pro are very very good and better than 1 part in a million.

"But what about that bump at -30dB? In the Pro it is now absent to exhibit a predictable noise vs signal level shape. Whilst we have no evidence that this is audible, it is fixed now.
"4/ Last but perhaps best of all, here is a graph of noise vs DC offset where the Pro eclipses the Sabre. Operating at better than -130dB, this is awesome performance which clearly contributes to better sound. Some notes from our designers regarding their thought process about a universal power supply solution. They have many advantages being physically small, with worldwide input voltages, cool operation and last but not least, an ability to provide 'always on' functionality whilst meeting the most stringent EEC and other jurisdictional demands for less than a fraction of a watt when in standby.

"In fact, the design time of the Veritas was to a large degree spent in making sure that the power supply did not affect audio quality at all. We chose a medical grade power supply of high quality designed from the start to not generate noise. We qualified ours as having no impact on the sound quality as determined by many listening tests; and in no way detracting from the measured parameters.

"You will see from the next photo that we put in place additional safeguards to ensure that performance was not compromised. Two layers of shielding are used: the SMPS is housed in its own metal enclosure forming a faraday cage around the module. We then we enclose it for a second time in a grounded metal cage or compartment within our aluminium chassis.

"Our entire signal path to XLR is true differential, not pseudo differential. Conversion to RCA is the only point where the signal returns to ground reference. Our seven selectable filters are 1/ brickwall filter; 2/ fast roll-off minimum phase filter; 3/ apodizing fast roll-off linear phase filter; 4/ slow roll-off minimum phase filter; 5/ fast roll-off minimum phase filter (default); 6/ slow roll-off linear phase filter; 7/ fast roll-off linear phase filter."