Travis and capo72, thanks for your posts and opinions.
Yes that was my reason for utilizing the Cleanbox, to up unbalanced RCA preout signals going into pro amps, like the PLX QSC 1104.
I also do not know about its ability to remove signal hum.
It did not add noise for me but everyone's setup is different. Was using this with a QSC PLX pro amp that has gain knobs for the left & right channels.
I think $60 shipped is worth the try. 🙂