Best Subwoofer Connection

OK, so I'm waiting on delivery of a JL Audio e110 subwoofer. I have a 2 channel setup. The on-line manual recommends connecting the preamp outs to the subwoofer's line in (l/r), and then going from the sub's line outs to the power amp. OTOH, I could just go from the second set of preamp outs to the sub's line in and run the signal in parallel without using the sub's internal xover. Which connection is preferred and best for a music only setup? I've searched this issue here, but I haven't found an answer that makes sense to me. Thanks.
Lucky dog. Great sub choice. You paid a premium for those excellent crossovers on those E110s so I would try running the preamp outputs through them first. This relieves the power amp and loudspeakers from heavy low frequency lifting. It will take some time and tweaking to get the sub integrated to your room and system but this is what I would do if I had a E110 or two.

On the other hand, You didn’t describe your system so my assumption is that you’re looking for bass extension, probably using stand mounts and not trying to get a few more low freq hertz out of big floorstanders.

In any event it’s your system and your ears so you may enjoy going back and forth between the two options. Have fun!

Have a read below. It cover the E112 which is the 12" version but the theory of using that Linkwitz-Reilly Crossover is explained.

Good luck and keep us posted.

I'm fairly certain that you will use your 2nd pre amp outs to the E110 directly, then you will be able to set up the sub using the external controls to adjust the E110 FULLY (you are going to have xover control)! Sending another pair of signals from the sub out, makes no sense in your system. Great SUB choice too BTW :-)

Matt M
Thanks, guys. I’m running a BAT VK-3i into a Musical Fidelity A300cr dual mono amp (225 wpc). Speakers are B&W N804s, and I’m looking for a bit more "oomph" in the bottom range. Does this make a difference in how to connect the sub?
Nice system! 

Don't forget to get your sub positioned first in the room before you tweak the crossover etc.

I would still run the preamp output through the sub as a first option. Then it's a matter of setting the crossover freq and sub volume. 

Then try the second pre out method.  

I am glad I am not your neighbor. 

Good luck.

OK, now I'm a bit confused. If I go from the preouts to the line in (and run the mains full), then I can use the external xover via the controls. If I go from the sub's line out to the amp in, does that mean I have no control over the xover, and it just is what it is internally? Sorry to ask somewhat noob questions, but I have had very little experience with subs.
I believe all equipment will worked best within their comfort zone, I recommend use the sub line-output high pass the signal to feed the power Amp, your Amp and speakers will thanks you for doing that. 
The sub has a crossover frequency knob that you will use to adjust the crossover point - that frequency at which all signals above it go to the power amp and all signals below go to the sub.  This is adjustible between 30Hz and 130Hz with 80Hz being a good starting point.  I would bet your setting will be much lower due to the good low freq response of those B&Ws and your taste for more bass.

The first option is to Run interconnects from the pre outs through the sub and back to the A300CR.  This uses the crossover in the sub and relieves the A300CR and B&W from low frequencies. You set the crossover to determine what the crossover freq will be.  Given what those B&Ws are capable of in low freq, you will have to adjust, listen, adjust, repeat.

The second option: Even if you decide to run a second output from the preamp and not use the hipass on the sub, running the amp and speakers full range,  you'll still have some crossover adjustment due to the overlap in frequency response between the B&Ws and the sub.   

@dbtom2  ... thanks, man! That's exactly what I wanted to know. I'm going to experiment ... now, at least I have a clue. Thanks, again.
Thanks to all who have commented and made suggestions. I now feel confident to proceed because of your assistance.
 The only time I found it necessary to use my subwoofers high pass filter was when my main power amp was not powerful enough to drive the main speakers. 

 Considering the many variables when adding a subwoofer system I would suggest you try both methods of connectivity as well as placement. 
Since my Primaluna integrated amp only has 1 pre-out for a sub, I run my Lawrence Violin speakers at full range. My speaker dealer suggested I set the cross-over at 45hz on my E-110. Besides the cross-over setting, it's important to set the phase on the E-110 also. I was told to invert the positive and negative connections on the main speakers so they are out of phase with the sub. Play some heavy bass music and adjust the phase on the E-110 until there is a null in the bass. Then reconnect the speakers to the correct terminals. The bass on my system became tight without any bloat.
I suggest you experiment and decide which way sounds best!    
You should take advantage of the xover option with the E-110 giving you a true bi-amped system. The less expensive Dominion does not give that option. That’s why the E-110 cost more because of the high quality xover is included.
If I were going to buy a sub that would be the one for me.
Enjoy it!!
UPDATE: The e110 arrived today, and I've tried it both ways. Running the N804s full range with the sub filling in the bottom end is much more engaging amd satisfying to my ears. When I put the sub between the preamp and the amp, the sound became thin and lifeless. Perhaps that's because having one 10" sub to carry all of the lower bass makes little sense in a set up with full range speakers. I could see putting the sub between components when running monitors which don't go down below 60 Hz or if I had 2 e110s. By running the N804s full range, I get the benefit of four 6.5" woofers plus the e110. The sound is very full, although I think I need to get used to articulate bass instead of the boomy, flabby bass I've experienced with other subs. Different strokes for different
folks, I guess.

Well, there you go. Once I saw your current loudspeakers I figured that you would be going in that direction. Still, given the high-quality of the crossovers in the JL E110, you have plenty of options down the road.

And perhaps adding a second sub might change things, too. My plan is to go with two E110s or E112s simply because of something I read someplace about how stereo mastering is now done down to below 20Hz. 

For me, I wouldn't be done tweaking for another month or so. Finding the right location for the sub, pinpointing the crossover frequency, setting the phase and, finally, making tradeoffs on the sub volume setting so I didn't have to get up and change it when the album changed.

On the other hand, you're a vinyl guy so you're used to getting up. ;)

Great sub choice and nice system. (Jealous grin.) Enjoy!

@dbtom2  ... thanks for the compliments on the system. I'm not a vinyl guy, though, it's purely CDs for me. And, yes, it will take some time to fine tune, but that's part of the fun. I think if you go with 2 e-subs, then you might have better luck than I with placing them between components.