Thanks a lot for the inputs.
I will try to put two resisters to see if there is any difference. However, there is no help for the noise when I short-circuit pin 2, pin3, and pin1. I hope my new one is not a broken one.
As for microphone, the noise performance seems worse. I use Rode NT-1A, with as little as 5 dBA self noise. Of corse, the phantom power is on. Making trims and level knots to the maximum, -36 dB of noise(hum) is shown in the volt-meter. Listening to the headphone jack, a huge amount of hum can be heard, much louder than the noise I heard without a MIC load.
The headphone is noisy I know, but when recording with trims turned to the minimum, the noise heard from headphone is much quieter than the case when the trims turned to the maximum. So I guess, in the latter case, the headpone noise should not dominate and the loud noise is due to recording noise not to headphone noise. I will use a quiter device to play the recording file and tell the difference.
I measured it in the midnight, when the environment is supposed to very quiet. However, listening carefully, I can hear some hum from the background, but as quiet as unnoticable. Using pillows to keep away the hum, makes no difference!
Kim