JBL B460 passive sub w/o external crossover unit

Nope. The passive sub requires an amp to drive it and your pre-pro provides only line-level outputs. You will need to add a power amp to run that sub.

Kal

i guess i was unclear...
can i connect the onkyo 886 (pre/pro) subwoofer out (XLR) to the bridged input (XLR) of the bryston (amp)and just use the pre/pro's crossover set at 60hz? and will it sound right without using the JBL dividing network BX63A (active crossover I dont have)?

So I hooked everything up and used audyssey to set up the sub. It sounds decent, powerful deep bass with no boominess but not how i remember it as a kid. Either my vandersteens have desensitized me or the lack of a active dividing network might be holding the b460 back

The bryston had a blown fuse and keeps blowing it just by being on w/o anything connected, (its being sent back to bryston 20 year warranty, wow way to stand behind your product), so im pushing it with a crown xls-402 thats 900w when bridged. I dont want to turn the crown all the way up so im waiting to see what the bryston is like when I get it back.

In the meantime I might try an active crossover out theres a few to choose from pyle or behringer around $200-300

You did make yourself clear in your question.....the answer was yes......

The BX63A puts in several dB of EQ boost at about a 26Hz center IIRC. So to make the sub sound as it did with the BX63A, you'll need to re-create this EQ curve.