@imhififan
I have converted the voltage to 120v. All is good except for one thing.
I used the 3-prong US power cord (the one with ground prong) to test.
When the amp is on and no music is played. If I stand close to the speakers, I can hear the white sound from the speakers.
I suspected this has something to do with ground prong so I removed it and tried again. The white noise disappeared completely. I played some test tracks for 3 hours and found the sound is exactly the same as when the amp was on Japan voltage.
I wonder if there is any way to fix the white noise issue with the ground prong?
Thank you.
Please note that, I filled the K3 and K4 holes with lead to strengthen the board.