Well, I'm supposed to bridge channels 3 and 4 on this amp to run my subwoofer, but no matter what I've done, the sub has not been powered once. I'm thinking either i'm not connecting the RCA's correctly, or there's something wrong with the amp.

Amp is CH 3/4 Filter LP setting, x1, input channel 1+3, 2+4. I also tried on 3/4 too.
I have 4 RCA's on my head unit, F+R plugged into front, F+R plugged into SW(subwoofer), nothing plugged into R(rear). Where should the RCA's be plugged into the amp, and do I have to switch any of the plugs in the HU?

 

if your speaker leads from the sub are bridged on the 3rd adn forth channel... then your RCA's needs to be plugged into the channel three and four INPUT and then up to your radio with the sub-out...

 

Ok, i've done exactly that. I think i've concluded that the amp doesn't work? It turns on and everything, but I don't think it's producing power. WOW. I really don't know what to do now, I bought this amp for $200 on craigslist, even picked it up from the guy, all I have is his phone #. Would it be pointless to take it to a shop because I was thinkin that, but it really just seems busted now.

 

have you tried hooking the speaker outputs and/or your rca's to a multimeter?