Originally posted by Michael C.: ...with no inputs whatsoever, with all trims completely off, at about 1/2 master volume I start getting a high mid-range, low high-end hiss.
quite pronounced at 3/4 full master volumne...
I'm not where I can try this yet, but ... might this be an artifact of open connections?
Try connecting a good (well-shielded, sturdy) cable (preferably XLR) to an input device (e.g.: laptop, iPod, keyboard), but don't play anything. Does the hiss increase or decrease?If
it decreases, then the System is apparently picking up some free-air signals someplace - that may be an issue of design for Hilmer (or others) to address. I know some audio components use input connectors which "short" the input when nothing is plugged in just to try eliminating most of those "nothing is connected but I get a hiss/hum" issues.(If the 'hiss' increases, it is hard to draw any conclusions, because there are so many possible sources of introduced, rather than intrinsic, 'hiss'.)