I am considering adding a subwoofer to my two channel den system. Problem: My Halo pre-amp does not have a sub-out and I have seen some interesting subs on e-bay that only have the RCA type connectors instead of the binding posts for speaker cable. Is there a way for me to utilize one of these rca plug only subs?
Since you must have preamp outputs, you can use a Y adapter to run the output of the preamp to the subs. Of course, this requires two subs, which you probably don't want for cost reasons alone.
It may be out of your price range, but it is worth looking for a used REL sub. They are very good, and they make it very clear that the high level (speaker) connection is the preferred one.
I'll second Thomas' recommendation of the REL subwoofers. They take speaker-level input and in my experience, blend easily with the main speakers.
Robert Harley