The A/C whine is definitely the exception and not the rule when it comes to the BlueBus. See, the core issue is that the rectifier diodes in the voltage regulator of your alternator are not fully rectifying the A/C into D/C voltage. That A/C voltage then leaks onto the D/C electrical system and is then picked up by the BlueBus. The reason the frequency (audible pitch) of the whine goes up with RPM is because the alternator spins faster with more RPM.

Most people don't have issues with the voltage regulator, so it's a non-issue. If you use the digital interface on the amp, it's also a non-issue because the whine isn't being converted into the digital signal sent to the amp (since it's 1s and 0s instead of an analog waveform).

In any case, if the afflicted user doesn't have the DSP amplifier to make use of the digital audio interface, then a ground loop isolator will remove the A/C whine. When it comes down to it, I sell a plug and play harness for a standard Amazon-special 3.5mm isolator.

With the 2.0 revision I wired things so that power and ground coming into the BlueBus *must* go through a common mode (A/C) choke with the hope of finally riding the circuit of any possible A/C whine.

-Ted