No, not without butchering the unit and voiding the warranty.

Besides, the Line-In is at line level. Presumably your tube preamp is a phono preamp, in which case you’d require that anyway.

Haha no intention of butchering the unit Ratty! And no I was not talking about a phono preamp. That of course needs to be in there either way, which seemed obvious to me. Do however get your confusion and could have been clearer about that. Thank you so much for taking the time to reply.

So no way to put a separate preamp (not being a phono stage) before the Sonos Amp then. That’s actually quite disappointing and limiting. Also because the Sonos Amp has only one input. Anyone another suggested solution that I might not be thinking about? Maybe I’m thinking to analog and the DDFA amplifier in the Sonos Amp has another possible setup in this use case?

I don’t understand why you’d want to do all this. Get a decent conventional poweramp for your tube preamp and, assuming you want Sonos functionality as well, get a Port.

That would require me to always use the tube preamp and and power amp to listen to my non-sonos speakers. I really like the always-on functionality of the Sonos Amp, so I can just stream audio (or Netflix from my iPad for that matter, living in a tiny apartment ) to the loudspeakers.

Well you’re going to have to choose which arrangement is more important.

Either use your TT+phono+pre-amp into the Line-In on the Amp (which can be set to AutoPlay the Line-In on sensing a signal).

Or get a separate conventional amp with the Port as one of its inputs. Choose one with a 12V trigger and the Port can power it up when you want to play off the iPad.

Wait, just so we understand each other correctly. You’re saying put the “TT+phono+pre-amp” into the Sonos Amp. Was that an error or are you saying that one can indeed put a pre-amp before the Sonos Amp?

Really appreciate the help and you putting your time into this by the way! Thank you.

You can put anything you like into the Line-In on the Amp, so long as it’s at line level. There’s an adjustment for sensitivity/gain to compensate for some variation in line voltage.

But, honestly, if you’re striving for sound purity -- and you must have a reason for wanting the ‘warmth’ (i.e. ‘nice’ distortion) of a tube preamp -- do you really want to push the signal through an analog-digital converter, followed by a DAC? There’s no analog pass-through on the Amp; an analog Line-In signal is immediately digitised on input.