Metrum DAC Burn-in?

Wondering if any owners of Metrum DACs can comment on the expected burn-in time before the DAC's character is fully realized. I’ve heard that Metrum units can take an exceptionally long time to burn-in - your experience?

I just picked up a Metrum Amethyst, and out of the box my impression is that it’s lean, just a bit bright, and lacking weight and body in the bass. Wondering if I should expect a great deal of change as it burns in? Or maybe I should trust first impressions?