junkyardawg1

After a recording I would open it in iZotope RX 5. It shows a detailed spectrum. Before the mod I would see noise in a few places above hearing range. It is now gone.

So... I finally got around to it! All I had to do was solder a small cap across the power terminals on the bottom of the power supply that feed the main board. So much quieter. One other thing, I removed the black paint off the screw that has an obvious ground terminal on it. Paint on the screw will prevent it from making a connection. It was a TDK multi layer ceramic cap at 1.5uF. Bought from Mouser for $1.69. Link is here. It worked for me but results may vary as it is a mod and it's the only one I have done.

I went through the same thing. That is how I found this page. Everyone raves on how quiet this thing is. I saw the same noise profile in iZotope. When I put the supply on an oscilloscope I was able to read the noise. The first thing I am going to try will be putting the supply in a faraday cage and checking it again. Great detective work on your part!