I tested it with different circuit, still has the same problem.   I sent an email to audioengineusa    it's audible in 2fts. Thanks

Hi all,   I've received my A2 today, I think it has problem.   My issue: When nothing is connected, (power adapter and speaker cables for right speaker are connected)   I mean, RCA and 3.5mm jack are not plugged. Then I turn my speaker, It makes a static noise.. If I concetrate to hear it...