2-channel stereo setup connection question

[opt-e]

Hi, I just recently got a STF-2 to use in my 2-channel system.

Currently I am running my sub through the high-level speaker inputs coming from my amp, which has two sets of speaker outputs (I'm using one set for the sub and one set for my mains).

My amp, a Rotel RA-01, also has pre-out jacks. I am wondering if it is possible to take the stereo pre-out's from my amp, and run them through a y-splitter to combine the signal into one mono signal that i can connect to the STF-2's sub-in.

Is this a good idea or are there sonic compromises in doing it this way? Either way I have to use the sub's internal crossovers.

[Lwang]

You can't do a reverse Y (2 into 1) because the signal from one channel's pre-out will flow into the other channel's, and vice versa. And since it is feeding into an input that has a lower effective impedence as its output impdence (sub's line level in in parallel with the other channe's pre-out), you would notice a drop in signal level, along with a possibility of severe distortion because the pre-out stage does not have the current capability to drive such a low impedence load.

You would be better off using the speaker level output.

[opt-e]

Thanks for such a detailed explanation :)