A cable routing reminder
If you have unshielded interconnects, be sure to keep them clear of any power cords - and power supplies.
A few days ago, I swapped the power cord on a component. The replacement power cord has a relatively mellow signature. But after installing it, the HF started sounding etched. This made no sense. I had solved that problem long ago. This was a mystery.
It turns out that when I replaced the power cord - one of my unshielded IC’s fell from its support - directly on top of the shielded power cord. Even though the IC was laying at a 90° angle, the negative impact was quite significant. After re-routing the IC, the smoothness returned.
So, if you have unshielded IC’s, be sure to re-visit their positioning. Actually, it can’t hurt to re-visit the routing of shielded IC’s, also.