[ICOM] 756Pro3 Noise Floor

[Ed K1EP]

While listening to a dead 6M band this afternoon, I noticed an interesting characteristic on my Pro3.  My setup had 50.125 on Main and 50.110 on Sub, with dual watch enabled.  I had the band scope on.  When I rotated the balance knob fully clockwise (msx Sub), the noise floor rose about 6dB.  This was observable on the band scope as well as the audio output.  It only happened when I maximized the sub band VFO.  I then swapped Main and Sub to make sure that it wasn't a characteristic of the particular frequencies and observed the same thing.  Rotating the balance fully to the Sub band, increased the noise floor.  Has anyone else observed this or can verify this on their radio?