Amplifier question

[calvynandhobbs]

Last week my amp decided to quit working for my subwoofer. I used a meter to determine that there is 12v going to the amp when the ignition is on. I noticed when I was doing the test that the green light for power is not coming on, but the red light for protection is. I'm going to try regrounding it, but is there anything else that I can try?

[BayouGold]

is there a fuse inside? check/rewire your ground &/or fuse(s). check your speaker wires & rca plugs for damage. if you disconnect your rca & speaker wires & it goes into protect mode, you could have bad output components. look carefully over the circuit board for swollen /busted capacitors, burned out transistors or broken lands.

[Gastank]

I used to work at a stereo shop in Norfolk and would see this friggin ALL THE TIME!!!! Normally kids not knowing anything about systems trying to bump with the big boys and screwing it up. Not to say that you did, of course, but it was more then a common occurrence.

 Anyhoot, if your getting the protection light and have 12v there I wouldn't worry about fuses or ground. it's going to more likely be dealing with the amp itself, normally something stupid. Depending on the make of the amp it could be a couple things.....

Anyway, here's a couple things you can try...
First is to check the Remote wire (normally blue) coming from the head unit, this should have very nominal voltage when the radio is on.
Turn the radio off and check the voltage of the blue wire again. if it still has voltage there could be other issues.

Next, mark your amp or take note of where the settings are, Gain/Low/Med/High etc... then turn the gain down to 0.
you might have to turn the radio off then turn it back on... to get it to take. This should make your protection light go out as the amp is not putting anything out... if the protection light does go out, SLOWLY start turning the gain back up trying to get it to the point of where the protection tripped the first time. if it lets you get to just under the level that if first tripped at then it's going to be an actual component in the amp, more then likely the power supply, that is "failing". If you can soldier, then it's an easy fix, radio shack should have something that would work.

(I have also seen where if the speaker wires become grounded this can happen as well, so take a look at those too.)

Can you explain your setup? Like how old the amp is, the head unit, so on...

Hope this helps. I'd come take a look at it if I could but for now it's strictly Web Wheelin for this guy.

[PaulW]

Sell ya a 600 watt JVC from my geo.

[calvynandhobbs]

I used to work at a stereo shop in Norfolk and would see this friggin ALL THE TIME!!!! Normally kids not knowing anything about systems trying to bump with the big boys and screwing it up. Not to say that you did, of course, but it was more then a common occurrence.

 Anyhoot, if your getting the protection light and have 12v there I wouldn't worry about fuses or ground. it's going to more likely be dealing with the amp itself, normally something stupid. Depending on the make of the amp it could be a couple things.....

Anyway, here's a couple things you can try...
First is to check the Remote wire (normally blue) coming from the head unit, this should have very nominal voltage when the radio is on.
Turn the radio off and check the voltage of the blue wire again. if it still has voltage there could be other issues.

Next, mark your amp or take note of where the settings are, Gain/Low/Med/High etc... then turn the gain down to 0.
you might have to turn the radio off then turn it back on... to get it to take. This should make your protection light go out as the amp is not putting anything out... if the protection light does go out, SLOWLY start turning the gain back up trying to get it to the point of where the protection tripped the first time. if it lets you get to just under the level that if first tripped at then it's going to be an actual component in the amp, more then likely the power supply, that is "failing". If you can soldier, then it's an easy fix, radio shack should have something that would work.

(I have also seen where if the speaker wires become grounded this can happen as well, so take a look at those too.)

Can you explain your setup? Like how old the amp is, the head unit, so on...

Hope this helps. I'd come take a look at it if I could but for now it's strictly Web Wheelin for this guy.

The blue wire has nothing going to it with the radio off and when I turn it on it has 12v so it is getting power through the blue wire. I will try turning the gain down like you suggest. I haven't moved any of settings since I installed it a few weeks ago with the gain at about 1/2. I have no idea of the age of this amp or sub since I picked it up from Axle in his moving sale and it was an old one that he hadn't used in quite a while. The radio is a Sony Explode that I bought from Walmart about 3 years ago that came in a package deal with 2 5.25 round speakers and 2 6x9s all for $87 so it's not the good stuff by any means. Because the radio doesn't have RCA jacks I spliced into the rear speaker wires for sound for the sub. It's not ideal, but it worked for a couple weeks.

[calvynandhobbs]

I went out and played with the amp at lunchtime. At 0 gain the protection light goes off and the power light comes on. I started to turn the gain up and it trips over the protection mode at less than 1/4 turn. Should I try disconnecting speaker wires to see if the gain will go up higher indicating that the wires are grounded out? I looked at them and didn't see anything that was questionable. Could it be that running the sub off the rear speaker wire is causing the trouble and I need to upgrade to a radio with RCA outputs? I'm really new to radio stuff. This is the first time I've had anything more than just a stock radio and speakers. I've never had an amp in a vehicle before.

[Gastank]

I went out and played with the amp at lunchtime. At 0 gain the protection light goes off and the power light comes on. I started to turn the gain up and it trips over the protection mode at less than 1/4 turn. Should I try disconnecting speaker wires to see if the gain will go up higher indicating that the wires are grounded out? I looked at them and didn't see anything that was questionable. Could it be that running the sub off the rear speaker wire is causing the trouble and I need to upgrade to a radio with RCA outputs? I'm really new to radio stuff. This is the first time I've had anything more than just a stock radio and speakers. I've never had an amp in a vehicle before.

is the sub the only speaker running off of the amp?

[rocket]

I went out and played with the amp at lunchtime. At 0 gain the protection light goes off and the power light comes on. I started to turn the gain up and it trips over the protection mode at less than 1/4 turn. Should I try disconnecting speaker wires to see if the gain will go up higher indicating that the wires are grounded out? I looked at them and didn't see anything that was questionable. Could it be that running the sub off the rear speaker wire is causing the trouble and I need to upgrade to a radio with RCA outputs? I'm really new to radio stuff. This is the first time I've had anything more than just a stock radio and speakers. I've never had an amp in a vehicle before.

is the sub the only speaker running off of the amp?

Yes, it is

[kirksjeep]

I'm not sure if they still sell them, but a few years ago when not every stereo had RCA jacks, you could buy an adaptor that had 4 speaker wire inputs, and 2 RCA outputs through a box.  From what I remeber the box dropped the level of the outputs.  I would think a stereo shop like Great Scott in Norwich would carry them, mabey even Best Buys.

[calvynandhobbs]

I'm not sure if they still sell them, but a few years ago when not every stereo had RCA jacks, you could buy an adaptor that had 4 speaker wire inputs, and 2 RCA outputs through a box.  From what I remeber the box dropped the level of the outputs.  I would think a stereo shop like Great Scott in Norwich would carry them, mabey even Best Buys.

I think I would just buy a new radio with RCA jacks before buying a box and trying to figure out where to mount something else.

[PaulW]

I'm not sure if they still sell them, but a few years ago when not every stereo had RCA jacks, you could buy an adaptor that had 4 speaker wire inputs, and 2 RCA outputs through a box.  From what I remeber the box dropped the level of the outputs.  I would think a stereo shop like Great Scott in Norwich would carry them, mabey even Best Buys.

I think I would just buy a new radio with RCA jacks before buying a box and trying to figure out where to mount something else.

i would upgrade to a radio with rca's.  i have an extra pioneer with rca's that i'll let go for the replacement cost of beer

[calvynandhobbs]

I'm bringing this back to the top since it looks like I'm in the market for an amp. I moved the box and amp from the XJ and put it in the TJ which has a Sony stereo with RCA outputs. I got everything hooked up, but now the power won't even come on at all for the amp. I have 12v constant on the power cable at the box and I have 12v on the blue wire only when the ignition is on. The odd thing is that the negative at the box is reading 12v also when I turn the ignition on and it's bolted to the seat mount for the back seat. I'm thinking the power supply is completely shot.

Any tips into what to look for in an amp. Do I want AB bridgeable, mono D, 2 or 4 channel? I've never bought an amp before except for this used one so I don't know what to even look for.

[PaulW]

I'm bringing this back to the top since it looks like I'm in the market for an amp. I moved the box and amp from the XJ and put it in the TJ which has a Sony stereo with RCA outputs. I got everything hooked up, but now the power won't even come on at all for the amp. I have 12v constant on the power cable at the box and I have 12v on the blue wire only when the ignition is on. The odd thing is that the negative at the box is reading 12v also when I turn the ignition on and it's bolted to the seat mount for the back seat. I'm thinking the power supply is completely shot.

Any tips into what to look for in an amp. Do I want AB bridgeable, mono D, 2 or 4 channel? I've never bought an amp before except for this used one so I don't know what to even look for.

alpine makes some really nice 5 channel amps that will run all 4 speakers and the sub in your jeep.  or just get a 200 watt class d mono block.  mtx makes a really good unit for low prices on ebay.  i had one pushing rj's 2 tens and it would rattle the windows in my house.

[kirksjeep]

I picked up 3 amps off of ebay when I thought the one in my XJ was bad.  When you come by tomorrow you can take a look at what I have.  I'm only looking $30 max depending on which one would work best.  I don't remeber the brand, but they were all guaranteed to work and I think 2 are 400W and one is 800W. 

[calvynandhobbs]

I picked up 3 amps off of ebay when I thought the one in my XJ was bad.  When you come by tomorrow you can take a look at what I have.  I'm only looking $30 max depending on which one would work best.  I don't remeber the brand, but they were all guaranteed to work and I think 2 are 400W and one is 800W. 

Sounds good Kirk. I'll give you a call around 10am to come pick up my oil drain pan and take a look at the amps.