Help My DAC sounds very noisy.....

I just got an EAD-7000 MkII DAC to test with my system. I don't know why the sound was so noisy. It's like when you record the music to cassette and you set output level too high then the High frequency signal was clipped. Another example, it's like when you want to listen to the radio station at 102.7MHz, but you tune the radio to 102.1MHz. You'll hear that level of noise. Sometimes the noise level was as high as the music.

I'm sure that I connect it right. I'm also certain that the noise didn't come from other equipment of interconnect since I also chained it with several DACs and other DACs worked fine. One thing I noticed was the EAD-7000 sounds much louder than other DACs. Is it because of the high level output of this DAC? If yes, how can I solve this problem? Please help me...