It does not look normal, but as the OP states, Devialet claims it's OK. Send the picture to Devialet support and ask. My Dialog looks the same. I did measure the temperature of my Dialog right now. About 56 degrees C at the heat sinks and 45-50 degrees C elsewhere. Quite hot IMO.
Living room: Kii Three/BXT with Control.
Den: Tannoy Precision 8 iDP with TS112 iDP subwoofer.
In the cupboard, waiting for a sibling: 1st gen. Phantom Silver running DOS1
My Phantom Voyage
Den: Tannoy Precision 8 iDP with TS112 iDP subwoofer.
In the cupboard, waiting for a sibling: 1st gen. Phantom Silver running DOS1
My Phantom Voyage
