With my Holo May Kitsune DAC attention must be paid to ventilation. Over-heating can be an issue otherwise. The original placement of the DAC and its separate power supply was technically inverted which was a mistake not made plain in the instructions. Placing the power supply atop the DAC - even with 3 inch tall spacers - could sometimes result in a chirping noise coming from the speakers. This was due, as I finally surmised, to overheating the DAC after an hour or two of playing. Placing the DAC atop the power supply stopped this annoyance.
My component rack is by the nature of my space vertically oriented with little lateral space around the component, so stacking a two part component such as the DAC and its power supply was an obvious convenience. Lately I have decided to just affix the DAC’s power supply to the side of the component cabinet thereby taking the over-heating issue completely out of the loop.