AC source noise filter for audio amps - activated by USB

I own a pair of AudioEngine A2 speakers and I really like them. To enhance my love for them, I planed an AC power source upgrade project.

I planed this project for two things:
1. Suppress the AC source noise - this is the primary goal.
2. Whenever I turn my PC on and off, I want the speakers to be turned on and off together.

The second goal, however, was a small concern, in fact. If you can say you are an audio guy, you must have heard some people say that turning amps on and off without turning down the volume may damage the delicate circuitry. However, at the same time, the others say that today's amps are advanced enough and they no longer need such circumspection. I believed the latter is true. But, just for peace of mind, I sent an email to the Audio Engine customer service and asked them to assure two things for me:

1. Unplugging the speakers directly from the AC source will not damage the speakers.
2. Even if it causes damage on the speakers, it will not void the warranty.

OK. The green light is on. The following are my AC filter design and implementation: