I am thinking about getting a subwoofer (the 505 was recommended) but am not sure how to hook it up to my old Adcom amp. The preamp and amp are old enough to not have any digital connections at all and no subwoofer output (but does have multiple sets of speaker outputs). I've been told this is an easy task and that it is a very tricky task. Which is it? This newbie needs help before she plunks down her limited funds. Thx.