Sound ok, consumption ok
Works perfectly, plugged into a speaker amp and also tried on ~40 homs headphones. I use it with an old switch-mode power supply, so it doesn't drain the phone battery (tested with a non-commercial power measurement app, Wattz) and I don't hear any audio artefacts (my hearing is lambda). The device draws ~0.7W from the power supply when the front light is on, otherwise nothing.