Amp input/output problem - JBL BP600.1

I have an JBL BP600.1 and it seems to work but it's really not loud at all. I have tried everything to make it go louder, all gain/crossover settings, high input, rca input. My rockford 4 channel with the same settings on my deck, pounds like it's supose to @ 200wRMS but when i switch my RCA over to my JBL, it works and it's clear but the speaker output is so weak it makes hardly any bass at all, its pretty much worthless. This thing is supose to push out 600wRMS. I have tried my power wires that works perfect with my rockford. Both fuses in the amps are good and i get no proctection light or any other indiaction of a problem. Obviously there's something wrong with the amp, does anyone know what is causing this and how to fix it? Thanks alot for every one's input.

oh sorry about that My sub is a Infinity Reference 1230w 12" 300wRMS 1200wPeak SVC 4ohms which in theory should be getting 300wRMS @ 4ohms from my JBL BP600.1 - My rockford is a P4004 and i'm using a pair of channel in bridge mode @ 4ohms to push the sub with a rated 200wRMS. I plan to put two infinity 1230w sub in paralel (@2ohms). I just used one sub to test the amp because i only have one sub in the car. (running off the rockord for now because the JBL amp doesn't work)

Do you have both RCA inputs on the BP600.1 connected? If not, just get 2 RCA splitters to hook the split left and right channels to both inputs... Did this with mine and it helped dramitically.

both RCAs were plugged in, i even went i connected my rear speaker wire to the high input, i honestly tried everything

ive got the same amp and the same sub. it hits hard and sounds great.

lol, i wish i had a waranty ! I wouldn't be asking how fix my amp if that was the case :P From the looks of things i should prob put it back in my closet until i learn how to fix circuits. I was just hoping someone on this board would know something about my problem. Thanks for the help anyways

you didnt have one of the drivers hooked up outta phase did you. Also did you hook it up properly being that its a dual mono design. You cant just bridge that amp or it wont work right, you must hook one sub up to each side or hook both up to one side, but not bridgeddouble-secret reverse-osmosis speaker-cone-induced high-level interference distortion, Its a killer

Sorry Revendarat but the amp is just a mono design and not a dual mono design. This is from the JBL manual BP150.1, BP300.1, BP600.1, BP1200.1 Connect the woofers to the amplifier, observing proper polarity. Although these amplifiers have a single channel, duplicate positive and negative connectors are provided to facilitate the connection of multiple woofers.