The issue is that these splitters are balanced with transformers. Transformers like these distort at higher levels, and the distort the bass frequencies much more than the higher frequencies. Since the splitters are made for mic level signals, thy "expect" a much lower voltage than a line level. As the level increases, the THD increases quite dramatically in some cases, and of course - distorting the bass most. Add to the fact that the 6176 seems to have a really high output. I would bet than "mic splitters" vary wildly in their ability to split bass signals at line level. I really wonder about using a $2500 preamp/compressor to plug into a $5 transformer, driving it at levels that it was not designed to take. The "standard" way to do it would be to run a DI and bring it down to mic level before putting it through the splitter, but that's got it's own problems. It seems as though the poweramp pass-though might be a good solution? But I guess then again, it'll need to go through a DI for the sound guy.