Next step is to throw out the switch power supply and move to a linear power supply. Many options to chose from which two popular LPS are the Sbooster and Teddy Pardo. I and a few others here have the Teddy Pardo and it made a noticeable improvement being, tighter deeper bass, fully presentation without losing the crystal transparency, wider and deeper stage, and improved PRaT. I don’t get some that say the RME sounds great but it’s weakness is its stage, as in my system, with room treatment and the Teddy Pardo I am blown away by the depth and stage wider than my room... the RME is definitely not closed in but I suspect showing the rest of ones system or a poorly treated room and maybe the lack of the Teddy Pardo with other users.
The RME Engineers are pretty proud of the ADI 2fs claiming in the extensive manual that there is no need to change out the SPS but I and others will strongly agree that is false and I’m guessing they’re just a little too proud of it as is. The Teddy Pardo is affordable and worth ever penny. Strongly recommend. If you opt to stay with the SPS, changing out the power cord does help but you’ll need to get a cable with the C7 plug which there’s many, or as some have suggested getting an adapter if you already have a cable you want to use. Lastly I leave mine on all the time as it does take some time to warm up and at first does sound a little thin or closed in at a cold start but still impressive.