Ptss, Power supply noise affects both digital and analog circuits. Its effects on digital circuits become a problem in in the GHz range. Even then the effects are limited to bit errors. You can't hear a bit error. In other words, you can't hear the signal until is analog. Therefore, if the 2Q is improving sound, that is because it's effects are reaching an analog circuit. There are several paths. One is power supply. A digital signal is a very dirty signal. It isn't designed to be clean because it doesn't need to be clean. Analog does need to be clean. The problem happens when these two worlds collide. How do you convert the digital signal to an analog signal without transferring the noise? You can't. You will always have some noise that transfers through. But if you start with a cleaner signal, then there is less noise to get through to the analog domain.
Therefore, I have no doubt that it is helping. I am saying the reasons are analog, even for a digital component.
