As an "odd" fix, try an attenuated Kimber Interconnect to match the impedances of the 2 units. If switching boxes are your thing, QED makes some great one. with a little bit of soldering, you can overhaul if with better cable, and maybe even some higher grade connectors (try some WBT's)
Switching device for speaker source
I have a A/V 5-channel 75W receiver. Now I'm auditioning a 2-channel 185W amp. I noticed the volume from the amp is way higher than from the receiver. This may cause imbalance between the central-channel and LR front speakers when playing DVD movies. Is there a device I can connect speaker wires from both receiver and aml to it and select the source depending on whether I listen to music or play HT stuff? What's its cost? Does it have any side-effect when doing so? Thanks. Mike C