I found the following in the public domain comparing the D1 and D2 in the event anyone is interested:
Differences we found on line for Lumin D2 and Lumin D1
- new generation CPU in D2, slightly faster processing speed
- D2 includes an internal 100/240 volt "switch mode" power supply in place of the D1 wall wart (Maybe from the Lumin M1 integrated amp/streamer)?
- The D1 allows for an optional Sbooster, external linear mode AC to DC power supply upgrade, the D2 cannot accept this option. D2 is AC powered.
- Logic and listening tests suggest better sound quality in D2, when compared to a D1, if and only if the D1 uses the included wall wart for it's power supply. However, the D1 with the external Sbooster Power Supply upgrade does sound significantly better because it is a linear mode toroidal AC to DC power supply. Many people have stated the D1 with the Sbooster upgrade, is very close in sound quality to the Lumin T1 which has a MSRP of $4000.
- It is well known that DC power is cleaner and quieter when compared to AC, especially if compared to a "switch mode" AC power supply as in the D2.
- Full size (D2) vs. mid-size/compact size (D1). Enlarged cabinet/board casing on D2.
- D2 supports DSD128 5.6MHz audio format and playback of all music file types (from the change in CPU).
- D1 supports DSD64 2.8MHz audio format and playback of all music file types
- Outputs and other connections on the rear panel are the same for the D1 and D2
- both Silver and Black color available in D2 to match consumer preference, D1 is shipped in a silver finish only
- IEC power cord socket used for the internal "switch mode" power supply found in the D2. Power cord included is for internal/external AC use only.
- The Lumin Application and streaming services support, are exactly the same for D1 and D2.
- D1 and D2 use the same DACs (Wolfson WM8741).
- MSRP D1 with wall wart: $2000, with Sbooster external linear mode toroidal power supply upgrade: $2375
- MSRP D2 with internal "100/240 switching mode" (consumer grade) AC power supply: $2300