In thread Is volume control in AD1939 analog or digital? Coleman says:
The volume control in the AD1939 is digital. Please be aware that attenuating the DAC signal will degrade the DNR of the output. Please consider adjusting the signal level in your system outside the AD1939.
I have disussed this issue with others and they all say that adding analog volume control after the DAC is a bad idea. I agree, there will be added analog noise for one thing.
The ESS Sabre32 Refrence DAC has a DNR of 129 dB, the AD1939 has a DNR of 112, 17 dB more headroom in the ESS DAC. With 32 bit DAC it will be possible to implement a digital volume control and still have hifi quality.
The SABRE32 Reference ADC has a programmable 8-band biquad filter which can be used for (RIAA) equalization. This is very interesting.
The ESS DAC/ADC combo has a couple of features that I would like to have from Analog Devices in an upgraded AD1939. It has been a long time since you upgraded your audio catalog.