Using variable allows you to use the Sonos app for volume control as well, and that convenience more than overcomes any theoretical loss of SQ. And that loss is also mitigated if you set the two volume control levels such that for most uses you do not need to drop the level on the Connect to below about 70%.

Thank you

With RCA output it’ll make very little difference whether it’s Fixed or Variable, other than the fact that using too low a variable output and compensating by winding up the volume in the downstream amp could degrade the SNR slightly.

On the digital outputs Fixed is simply the PCM output from the decoder, without any DSP. With Variable there’s some DSP applied, to ensure that the digital output doesn’t clip at the highest volume/EQ settings.

Thanks Ratty. 
 

Would I get better SQ using the digital output? 

How long is a piece of string?

The DAC in the Connect is okay (but the Port’s is evidently an improvement), so it all depends what outboard DAC you were proposing to use.

Thanks