[Infiniti]

I've been using a pair of A2s for a while, until recently I've upgraded to a pair of bookshelves, a sub, and a stereo receiver. It definitely sounded better, but the receiver is slightly faulty and won't drive the bookshelves if I plug a pair of headphones in and unplug them later on. (yeah that stuff was sort of unrelated but if anybody has any suggestions it'd be great; the receiver is a Yamaha RX-E200, old stuff.)
 
Anyway, I've stumbled across a deal for a NAD 7125 receiver and a pair of Polk T15s for under $150 CAD. Looking around, it seems like this would be a decent deal, correct?
 
However, how would I go about connecting my sub to the new system? 
 
 
Thanks!

 

[slidesear]

A crossover would work but you have to be careful with how much load you are putting on the amp.

 

[trog]

Any amp could be connected to an active sub via high level input if the sub has em' so use speaker wire from speaker out of amp to high level in on sub and set crossover frequency appropriately
See after 1:17

 

[JRG1990]

Or you could get a sub with a low-level pass thru.