Amp help; Jl audio slash v2

[loudlittlefvkus]

I have a Jl audio slash v2 1000/1, i bought it used from craigslist a while ago for like 200 bucks. (buying it from craigslist is probably my first problem, i know. haha) but while i was messing around with the controls, trying to get everything right, i noticed that when i have the Infrasonic filter on, it doesnt give any power to my subs. nothing. i was wondering if anyone had any ideas on why that might be, ive read through the manual and made sure i had everything else all right, its not an issue right now but im getting some SA 12s in a ported box soon and want to use that. could something on my head unit be cancelling it out, or could i have something set up wrong on the amp? thanks for any help.
here is the amp manual: http://mediacdn.jlaudio.com/media/mf...pdf?1305783842

[Sonic.]

Under the infrasonic switch there is a dial label 15 to 60, where is it set at?

[loudlittlefvkus]

i had it set around 30, low pass filter at 120

[loudlittlefvkus]

i dont completley remember what i have all my controls set at but i can check tomorrow and i'll post them, im sure that will help

[Sonic.]

Sub should play with that setting, unless some thing is wrong with the amp.