When I turn the volume on my amp around 60% or higher I get some interference noise using my mad dog and a friends Sony V600. The sound with the mad dog is a surging "swoosh/soft static" noise, but does not happen every time i turn the volume up. With the V600 i get a surging high pitched whine that reminds me of radio noise, and other times a long high pitched "siren" noise which I can hear every time. The volume of the noise will vary and sometimes the surging will come in intervals of 5-6 seconds and other times completely random. The noise is only present when the i20 is powered on(in standby and while on pause). I tested plugging the i20 into another outlet, different cables, and moving it away from my other equipment, but the noise is still present. When i moved the i20 it did seem to make the volume of the noise change randomly. The amp and DAC were tested separately, and are completely silent until I add the i20 into the chain. The sound is not present with my LCD-2 or HD650. Any advice would be great so I can figure out if I have a defective unit or if this is something I shouldn't bother worrying about.
i20 with iPod classic
Blue jeans cables