Well, I finally hooked up my amp and sub about 2 weeks ago. It's a 12" Jensen XS sub, in a single enclosure, hooked up to a Jensen xa4150 amp. My problem is, the other day, I was driving along listening to a pretty high bass song, and all of a sudden, no bass. So today, I checked all connections, and all fuses, and everything is fine. The amp has two lights on the side of it, power(green) and protect(red). When the sound is low, anything about 5 or less, the power light is on, and the sub is going (barely, but I can feel it moving). When I turn the sound up past 5 or so, the light switches from power to protect. I checked the ground and everything like that, and I cannot figure out what's wrong with it. Is my amp shot? Please let me know, and give me any ideas! Thanks! -Brad

Amp Specs are:

4 Channel Amplifier
600w Peak power
2 ohm Stable (Stereo Operation)
Tri-Mode Operation
Variable High Pass Crossover (40-240Hz)
Variable Low Pass Crossover (40-240Hz)
12dB/Octave Crossover Slope
6dB Fixed Bass Boost @ 45Hz
High Level Inputs
Input Level Control(s)
Pass Through RCA Outputs
Extruded Aluminium Heatsink
Top Mounted Controls
Thermal/Short Circuit Protection
4x75W RMS Power Per Channel @ 4 ohm
4x100W RMS Power Per Channel @ 2 ohm
2x200W RMS Power Bridged @ 4 ohm

and here's a link to the amp: http://www.crutchfield.com/S-y75N4OH...120#morephotos

 

Sounds like you may have killed the voice coil in the subwoofer. Confuses alot of people when it happens. Try gently pushing straight down in the center of the sub and feel if there is any scratching or if it will even move at all.

Also, try taking the sub out of the box and looking at the leads. If you have one that is badly damaged (from clipping, or overdriving) it may just barely make contact when the sub isn't moving very far, but when cranked, it may short against something.

If neither of those is the problem, you may figure out what is going on in the process.

 

thanks for the response, but would this cause the amplifier to switch from power to protect?

also, i don't think it's the amp, because i went to wal mart today and picked up a pioneer 2 way amp and hooked it up, and i still didn't have any bass. i did this just to see if it was, in fact, the amplifier, and now i know that it's not.

any other responses or thoughts are welcome, please let me know! -thanks!-brad

edit: so i definetly think that your answer may have been the correct one, because i went out to my car and had my gf start it while i held in the center of the sub. i told her to turn the radio up to about 10 and put it on the same sone. well, while i was holding the sub down, not allowing it to move, the green power button was on the amp, but when i let it off it gave me great bass for about 2 seconds, then the amp switched to protect and i had no bass from the sub. does that sound like what you were talking about, never satisfired?

 

Yeah, that's pretty much what I was saying to do. Most of the time you can do it with the car turned off and feel a bit of a scratch, or it may just be harder to press the sub in. A sub in good condition will actually allow the cone to move smoothly when pushed in by hand.

Unfortunately, it sounds like you are due for a new sub.

 

Also... I don't know too much about that amp, but generally 4-channel amps are not very well suited to run subwoofers.

 

yeah i figured after a while of looking at my sub and realizing that there's no way to get at the inside of it, i figured i'd need a new one.

oh and about the amp, i have it set to 2 channels and i have them bridged to run just my one 12. it works out really nice.

 

4 channel amps can run speakers and subs fine with proper cooling, just make sure you have your crossover set right. if your not going to amp your speakers too then i recommend selling it

 

Sorry to tell you this, but you blew your sub.

 

How is the VC moving? Do you have another amp?

 

if you do bridge the amp, you have to make sure that the ohms are in sync.