Thid idea is just the ability to use the DAC-1 as a preamp for hometheater use in a simple way:

Let the analog input have a switch to allow fixed volume output. Let's say a switch on the board that bypasses the volume control for the analog input ?

This way one can use a hometheater receiver / processor with analog output for main channels, let the receiver / processor control the volume, and when I listen to CD/PCM or other digital input signal, the analog volume control will be used !

I think this "Benchmark DAC-1 HTB" (Home Theater Bypass) will make the final statement ;-)