Help with subwoofer implementation


I need a little help in incorporating a sub into my 2 channel system...  Not sure what way would be best?  I have a Pathos Classic One integrated amp.  I am using the balanced inputs - source is an Audiolab M-DAC Plus.  Using the Mdac in fixed output mode and using the Pathos for volume control.  Speakers are a set of Magnepan 1.7i's.  I would like to augment the low frequencies with an adjacent subwoofer (room does HT too).  Sub has speaker inputs, and both single ended and balanced inputs for LFE, Left and right channels. 

My conundrum is how to best get a signal to the subwoofer...  I was thinking about using the single ended outputs from the Mdac, but that would entail using the Mdac for volume control too instead of the Pathos.   Any suggestions as to if that would be the best solution, or if there is a better way?

Thanks in advance for your input!

With a little more reading, it seems that the best choice would be the high level inputs...  Correct??  I was unsure about the impact of a second set of speaker wires driving the subwoofer off the amp, but it seems this would be a non-issue?
Some of the Rythmik subs offer high-level (power amp output) inputs, as does REL.