So you’re just looking to raise the volume level of the Turntable to match your other audio sources, is that correct? If so, what is the current "source level” set to on the Play:5 line-in? —> ‘Settings/System//Play:5 room name]’

Thanks Ken. Level 5, in between airplay-4 and Mac Computer-6. Also, if I want to split the Bose up, into 2 sets of controllable speakers, I assume another amp will have to be added/purchased?

You could add an impedance matching volume control to the Bose lines and adjust the volume manually to where you are happy with it.

Try increasing that line-in ‘Source Level’ to a higher value and see if that aligns the TT audio output to your other sources. I have mine set to level 10 …and to answer your other question, if you want different audio to play to each of your 2 sets of Bose speakers ‘at the same time’ then yes you will need another Sonos Amp to do that, but if you want the audio (same/different) to play to just one set of speakers, or the other, then you could add a switch to do that instead, plus it’s a cheaper option. This YouTube video shows the kind of switch I mean…

Thank you Ken. I will try @ higher level. On the “switch”, I will review and let you know why I decide. I appreciate the direction. 

Hey Ken, the switch is exactly what I needed, thank you so much.