Your subwoofer does not have crossover and volume control? I recommend getting an audio subwoofer. Your system looks worthy of it. I would not trade in an Audio Research piece of gear unless I was upgrading to another one. I don’t know any high end audio preamps with an LFE. That is in a different realm, home theater. If you want good sounding audio for music, you want a subwoofer designed for it. .
Unless you are converting to a home theater system... in which case you will likely be severely compromising your two channel audio. If that is what you want... that is ok.
Unless you are converting to a home theater system... in which case you will likely be severely compromising your two channel audio. If that is what you want... that is ok.