Hi,
Just received my WA5-LE before the new year!
However, I hear a quite noticeable background noise from the high impedance port on both sides. The noise does not go away even without a source input. I think it is more like white noise, rather than hum. The noise is not trivial even at zero volume, and it gets larger as I turn up the volume.
The low impedance is much better. Still a bit noise. The noise from the low impedance at the highest volume is lower than that from the high impedance at the zero volume.
Here is what I tried:
I swapped all tubes, left to right, and right to left. Did not help.
I also tried to tune the noise tuner under the amp arm. Some hum showed up however, while the white noise persisted.
I tried the amp at various places inside my home, all the same.
Tried different headphone, hd800 and hd600, both are the same as well.
I swapped several power cable, including a fake power cord without ground. Did not help.
Following this post,
http://www.head-fi.org/t/435096/question-about-hum-noise-on-woo-wa5#post_5856884, I removed the input tubes (6SN7), and heard about 10 seconds. Initially, there is a hum. After 4 seconds, it become quite.
I have so far burned it in for around 8 hours. The issue is not getting any better. Does anyone here experience something similar? Is there anything I can do to nail down the issue?
Thanks in advance!