AwesomeOkay. I'm going to stick with my current DAC and only change it if I want new functions. I've learnt that because my DAC increases the bits to 32 I don't have to worry about the noise when using the DAC volume control. I'm going to return the Audiophonics HPA S400ET when it arrives. This amplifier is so good. Thank you to everyone who's helped me in this thread you gave me great advice. Thank you particularly to @marX for suggesting I get the Audiophonics NCX500 (HPA-S600NCX).
I have to wait a bit (to purchase one for myself) as we are house hunting.