just purchased A18 to match with D18. background noise of A18 is so BAD !!!!!!!!! not worth USD 899.
Because I, too, experienced background noise with the A18 and my AKG K702's, maybe my input can help you. Actually, it wasn't something permanent, it would come and go. As for the noise per se, it was more like hearing frequencies, like the sound of a radio when you change the frequency. It would last for 10 seconds, and then it would go away. At first, I was worried that the A18 was faulty, but then I remembered that I had experienced this in the past with my stereo amplifier (when I had no head amp and I used the headphone out of the stereo amp), only it wasn't that obvious, and it only occured during summer.
I think you get my point. Obviously, now with the A18 being much more detailed than my stereo amp, I could hear everything clearly -be it music or power line noise. I should add here that I don't use a separate power line, nor any power conditioner or even a specialized power cable (I know, I know, I must change that), and that the A/C was working 24/7 -mine and the neighbours'. When I took the A18 to my friend's house, who uses a separate power line, the noise 'magically' disappeared. And now that the weather is cooler, even in my house I don't experience any noise at all.
Bottom line: With the 62 Ohms K702's,
the A18 is dead silent. Even with the volume all the way up, I can't pick up any hum or static. So, either this is a grounding issue, or, worst case scenario,
your A18 is faulty. In any case, there's definitely something wrong, as the A18 has a dead silent background. So, I would recommend you do what I did. Try it in a different place, preferably somewhere with a good power line. If the problem persists, then most likely your unit is faulty.
