Sub / Amp Problem

I finsihed installing my sub and amp to find that it isn't working. The amp is getting power, but the sub is doing nothing. The amp is a 2-channel amp that is bridged into one sub. I have a good ground. The RCA's are hooked into the rear Pre-outs on the HU, Remote is spliced into the power antenna wire. I know that all connections are strong.

I've tried changing the HP/LP/Flat to all three settings, I started with the gain all the way down then went up and back down to no prevail, tried changing the amp from stereo to mono and back again, taken the x-over throughout its range....nothing is works.

Any thoughts on what may be wrong? For the remote wire...I cut the power antenna wire in half, stripped both halves and twisted them together, then I stripped the remote wire and twisted that around the two twisted halves of the power antenna wire, then I put a wire nut over all three and electrical tape around that. Is this correct? Should I have just crimped the remote wire into the half of the power antenna wire going to the HU and left the other half alone?

It's really frusterating when you finally have everything hooked up to find that nothing is happening...please help me.

if the amp is turning on and off with the deck, then i would assume your remote wire connections are working fine.

it seems like its not getting a signal from the HU if the sub isnt playing any music. make sure the HU is setup to send a signal to the RCA's, as on some decks you have to program it correctly. on my pioneer there is an option to turn the sub on or off.

also make sure you have the correct wiring from the amp to the sub. you may be trying to bridge the amp with the wrong two connections.

your best bet is to try and borrow someone elses amp and see if you get sound out of it. also try using someone elses sub with your amp to see if that works, to try and pinpoint the problem.

I think I know your problem. Your power antenna only gets power when you use the radio, not the cd player. So, when you have your radio on the amp gets the signal from the remote lead to turn on, but when the radio is off and your using the cd player, it's not getting the signal, so it's turning off.

Tonight I'm going to take the sub out of the box to make sure that the speaker wire going from the box to the sub didn't get disconnected while installing the sub. I'm going to feel pretty stupid if that is the case (but also relieved if that's the only problem).

Since I have the sub bridged and so it is using both channels, I should have the amp set for stereo, correct? Or should it be in Mono?

I will try and post some pics tonight of the install to see if you guys can see something that I have connected wrong.

I think the remote is fine...the amp is turning on whether I am using the radio turner or CD player, but no music from sub in either mode. As far as the RCA's, I have two pre-outs (front and rear) on the HU. According to the manual, they are both fixed 2V pre-outs and there is no subwoofer control on the HU. I have the amp hooked to the rear RCA pre-outs. I may be getting a new HU soon though.

Thanks for any further help.

Well, the sub moves a "little" bit, but I have to have the gain all the way up and the HU pretty loud...so something isn't right. The amp is a JBL P180.2 which puts out 360wrms when bridged and the sub is an MTX Thunder8000 which is rated to 400wrms.

We used a tester and the RCA's, power, remote, speaker wire...everything is getting plenty of power.

I triple checked, and I do have the sub hooked up to the Bridged terminals...

Don't know what to do.

your amp should be set to mono. What gauge power and ground wires are you using?

4 ga ground...4 ga power going to a distribution block with about 2 ft of 8 ga going into the amp, 12 ga speaker wire

well, i'm pretty sure this isn't the problem, but you should really be using the same size ground as power.

If you're getting power to your sub and everything checks out, the sub has to be the problem.

try to turn the frequency up and then change the gain. i had the same problem and this seemed to fix it. list the settings that you can change on your amp and then maybe we can help you from there.

it is possible that your amp is blown and the power light still comes on, i had the same problem with my amp so i opened it up and seen it was all black on 1 side, burt it looked fine from the outside and even the power light still came on, so give it a try, also you could connect your subs to the normal speaker wires from the radio to see if they are working

If the amp is blown, then it is a DOA unit. It is brand new.

I'm going to see about having my friend come over so I can hook my sub up to his amp and his subs up to my amp...See what works and what doesn't.

A question about that...he has two subs that I believe are wired to be a 2ohm load coming out of the box (he has a mono sub amp). Should I hook his subs up to just one channel on my amp???...if I bridge it, then it will be too much...my amp only handles 4ohms bridged, but can do 2ohms in each channel.


If ya can't tell...this is my first install :banghead: :)

if its possible, try to recreate the same situation that you are trying to correct. that means hooking up just one sub to the amp, rather than having them in parallel to make a 2ohm load.

if thats not possible, then match the impedances so you dont burn out the amp. no sense it creating problems while you are trying to fix them. even with the amp working in stereo, you should still be able to get some sort of response from the subs, at least more than you already are, if the amp is working.

if nothing else, at least this first install will teach you how to troubleshoot a system really well...

sounds to me more like a faulty equipment problem then a faulty install problem