Generally, how noisy is the 680? Are the 1/4" inputs noisier? I've recently recorded 1/4" mic-in, gain on high and had LOTS of self noise. Just a constant humming sort of hiss in the background. One time a relatively quiet, but still fully amplified show with as much gain as the machine had and the recording is basically unlistenable. Just last night ran again, mic-in, gain on high, but trim only at ~11. Still VERY noticeable noise during the quiet parts. Is this normal?
When running XLR in it has been much quieter. Maybe just simply since less gain was needed? I can't remember what my settings were for XLR in.