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Amp Shuts Off


highhighs

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i have the 12" sub (4ohms) connected bridged to the usc2100 amp . when i raise the volum to 15 the amp shuts off(the bass isn't load befor it shuts off its barely audibal). i guess its going to protection mode but i dont know why. its showing 12.4 when the car is off accross the + - terminals but how can i test the current ? and how much should it draw, or how can i debug it. i have the ground connected to teh bolts of a circular aluminium thing under the trunk carpet (near teh back seat).

edit: i just noticed that teh midle blue led of the 3 blue leds is off (when the amp is on) can somebody with this amp or knows about it tell me what this is (bing_o?).

note that the amp isnt always in protection mode only when i increase the volume to 15

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are you sure that whne you bridge your amp it's putting out a 4ohm load? If your sub was 4ohm and your amps pushing 2ohm when bridged, that would explain when it's in protect mode and shuts off at very low levels. Is your sub a single or dual voice coil? Try running your sub off of 1 channel unbridged and see what happens, or if it's dual voice coil, set it up in serial mode(or maybe parallel, whatever is the opposite of how it is now). just a few suggestions

pyro

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or you have a blown transistor or whatever it's called in the amp...my old Lanzar amp did that to me....i'd turn it up past a certain point and it would just give up and go to protection....one of the channels could be bad also....

I would first try it unbridged into one channel, then check for melted or burned internals...

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Based on your signature:

1 Pioneer 305F spec-> RMS@300W, MAX@800W.

1 usc2100 spec -> 2x100W@4 ohm,2x150W@2 ohm, 1x300W@4 ohm.

From this spec, I conclude that you overload your system by using 2 pioneer subwoofer. And if your subwoofer is DVC (Dual Voice Coil), your system is definitely overloaded. (I just don't believe the US coustics can run 2 Ohm stable)

Try by using just 1 subwoofer and use the mono bridge. I bet it work alright UNLESS you burnt some internal parts because of the overload.

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was it working before? or you just got it and it doesnt work? sop basically even if yo ujust powerd it up, it still does it? if so, there are only two possiblities:

1. broken amp

2. incorrect impedance. waht impedance are your subs? how are they wired up to the amp?

b

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It is a single sub single 4ohm coil so rule out overload. it was woking fine until it shut off (no tprotection, no power) i read across teh power terminal 2V so i changed the location of ground now it reads 12.4V but it goes into protection mode and the middle blue LED is always off (i dont remeber if it was on befor).

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Guest DougK

I know this will sound stupid but, my JL started doing this to me 2 days ago. I was freaking out... what was it? Bad connection at the sub (had shaken loose). Up untill the point it completely disconnected it was doing exactly the same thing.

all better now :D

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i just went to the car, i noticed that if i move the balance to the left(all the way) no sound is produced when i move it to the right(all the way) their is sound. now the sub is bridged ? what does it mean? and i noticed that only when a hard bass note hits the amp goes to protection (the protection light come on) for 3 seconds then out till the next hard bass.

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either bad amp or bad output section from your headunit or bad rcas, tryrunning a new rca cable, just do it inside the car and dont stuff it under the carpet until you know wahts going on...

does it still go into protect when you have it full to the side that works?

b

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it worked for a month until it shutoff itself then problem started. if it had bad ground will it work for a month or does bad grounding or ground loops burn internal circuitry? coz after it shut off itself it was showing 2v acroos the power terminals, then i change the ground spot.

i tried debugging it today:

1- the sub shows across it 3.4ohms, good.

2- i tried connecting the sub to the right channel alone it works and does not go into protection mode

3- i connected the sub to the left channel alone it does not go into protection mode but it has lower volum than the right channel (i played with the level input even at the highest setting it plays bass but with less volum than the right channel)

4- when i bridge them at 20 HU volum and adjust the input level the amp goes into protection mode not so loud bass.

5- i checked the ground it shows continuety with the body of the car

6- across the terminals of the amp it shows 12.4volts with the car off.

i need to know about the midle blue LED being off if it means something. nothing is stated about it in the catalog.

can i test the rca cables without buying a new set?

and if its a problem with the amp i prefer to fix it myself coz i dont live in the us and shipping would cost me more that the amp itself. i have some soldering knowlidge if its some part i need to change but i need guidince.

thank you.

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just thought of this, does your amp have a bass boost knob? try turning it all they way down and turning your input sensitivity up until you like the volume level. My friend had a concept amp that would go into protect if the bass boost was set and the input sens was kinda high. I'm not a big fan of bass bost anyway since it makes the bass sound kinda "fuzzy" and not as tight. just a thought. as far a wiring goes everything looks good, testing the RCAs sounds lke the next step to me.

pyro

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i guess it is the rca cable, i used a Y addaptor and connected the suposidly good channel cable to the amp, it did not go into protection even at the highest level input. i tried the otehr channel, it also didnt go into protection but the volum is less at the same input level. bass boost is 0db , oh well im going to get a new rca and try again.

should the rca cables have same volum on them? and is the base signal sent to both channels at the same level(mono)?

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