These days, my research project on the experience of listening to music on the wiim ultra has some problems with the line out port. The sound from the line out connected to the amplifier does not sound as good as the headphone port connected to the amplifier. In fact, I have been trying that, the sound from the line out is uneven and sometimes the bass suddenly reduces the amplitude and loses detail in the low pitches. I do not know what the cause is, is it because the connection cable is not up to standard or not? I have tried with 2 different amplifiers and speakers and the result is that the headphone out port does not seem to have the problem of the line out port.