Dac for Sonos

Hello all,

I've got a Linn Majik DSI and would like to get a standalone digital source to sell it and finance another amp.
The next step in the Linn range is too expansive for me and Kinsky is not robust at all and I'm kind of fed up with it.
I'm thinking of changing for a modified Sonos, running through a Dac + maybe at a later stage Synchro Mesh.
How much (SQ) would I lose compared to the DSI?
I know there are some threads about DACS but the scene is changing quite rapidly.
What DAC around 1000$ maybe less would you advise me? Every review underline the USB part of the new dacs but never the digital inputs (the Sonos doesn't have an USB output); is a spidf to USB converter a smart move?
I don't care for hi res as well (and I can't with the Sonos and I got my TT for that), red book CD suits me well.

Another option for me but more complicated and expensive would be mac mini + DAC if the SQ is really better than a modified Sonos + reclock + dac

I will listen a stock sonos + rega dac at the end of the week and I will take the Rega as a point of reference soundwise and moneywise for alternative products.

Thanks for your inputs!