Amp keeps going into protection mode

D

DLSHORT21

New member
I decided to install an amp and sub in my 4runner that I've had sitting in the garage for a while. My runner had amp wiring already installed by po. I changed a blown in line fuse and hooked up the amp to see if it powered on and did so with no problem. Then I ran power from the amp to the subwoofer. It's a 2 channel amp and the sub is a dvc 4 ohm 12". I bridged the subwoofer and made connections but when I turn on the ignition the amp goes into protection mode. I believe the subwoofer is wired right.

What could the problem be? Any help is appreciated. The amp will stay on not in protection mode with the rca cables unplugged and or the sub not hooked up.
 
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DLSHORT21 said:
I decided to install an amp and sub in my 4runner that I've had sitting in the garage for a while. My runner had amp wiring already installed by po. I changed a blown in line fuse and hooked up the amp to see if it powered on and did so with no problem. Then I ran power from the amp to the subwoofer. It's a 2 channel amp and the sub is a dvc 4 ohm 12". I bridged the subwoofer and made connections but when I turn on the ignition the amp goes into protection mode. I believe the subwoofer is wired right.

What could the problem be? Any help is appreciated. The amp will stay on not in protection mode with the rca cables unplugged and or the sub not hooked up.
Click to expand...

Are you disconnecting the sub at the amp end or the sub end? If at the amp end, try disconnecting at the sub end to rule out a short in the wiring. Protection mode is normally because there is a short or too low an impedance on the load side. So recheck that bridge set-up. Put an ohmmeter on it. Maybe you are shorting the load. If all else fails, try a temporary hook-up with new wires from amp to sub. PO wiring is always suspect.
 
Gotta run the sub in series not in parallel. Your ohm load is sending the amp into protection. 4 ohm dvc in parallel will give you a 2 ohm load. When the amp is bridged 4 ohm is the typical limit.
 
Just because it's a 2 channel amp doesn't mean you can run it parallel. Is your amp rated to run at 2ohms? There are several reasons why this is happening, and one I already stated. You could also be drawing too much current out of the amp because it can't handle the load and is not getting enough power. Could also be a bad ground, check the amp fuse, and check the main fuse.
 
MStudt said:
Just because it's a 2 channel amp doesn't mean you can run it parallel. Is your amp rated to run at 2ohms? There are several reasons why this is happening, and one I already stated. You could also be drawing too much current out of the amp because it can't handle the load and is not getting enough power. Could also be a bad ground, check the amp fuse, and check the main fuse.
Click to expand...

I will have to check this out tomorrow morning when I get time I know it has to be something most likely with wiring. All the fuses are good possibly the ground.
 
Thanks for all the advice I may have figured out the problem. I ran the wires to only one coil which it has two and it wasn't even a series connection. Not off until 11 pm so I will post the finding to this when I get a chance later. Hopefully hooking up both coils and in series will correct the problem.
 
In that case I would re-check your grounds.

Also what gauge cable are you using? I would highly highly recommend 4 gauge cable.

(I forgot to add that I once had an Alpine amp that claimed it only needed 8g but it kept shutting off, when I switched to 4g the problem went away entirely)

This is for several reasons ....

1) most stereo cable isn't copper, it is actually CCA or Copper Clad Aluminum. For this reason it is inferior to copper at least for the purpose of power throughput. It is still ok for most stereo uses but just know it isn't copper.

2) most cables aren't actually AWG even if they imply it is so. A specification on packaging may say something like 4G but they never say 4 AWG which is the real specification for contractors and electricians.

What does this mean? Well when you look up Wattage vs. distance vs. Cable Thickness (AWG) charts they are almost always referring to real AWG and real copper. As I already mentioned CCA is inferior and about 66% as efficient as copper (quick Google search, no hard references) and the 4G is probably not 4 AWG.

So you may look at a chart that says 8 AWG copper is more than good enough to push 600 Watt about 8 feet without issue. But what most don't realize that their 8G Amazon/EBAY Copper Clad Aluminum cable can't come close to this.

How do you make sure you are covered ... it is simple. Buy 4G always and preferably copper but that isn't realistic for 95% of stereo builders. So go with CCA but make sure it is 4G, as close to 4AWG as you can find and you will probably be covered.

I have 4G but copper that I bought in 2000 (long @ss time ago before the price /lb went up) connected to a distribution block underneath the rear seat. From there it splits to 2 separate amps via 4G CCA; each cable is about 3-4 feet.

BTW a great place for a ground is the seatbelt connector on your rear seats. Both the one by the driver side rear door and the one in the middle of the rear seat. Grind off the paint with a file or sandpaper, remove the bolt, wrap the wire around the bolt, re-install. Excellent ground achieved.

Since I'm dolling out advice I also always advise to run new power and ground (probably 12G) to any aftermaket head unit straight from the battery (with a small fuse of course) using the firewall pass-through.

:guitar2:

Refers to copper and 4 AWG ....
 

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Thanks again Brian I will re check the ground right now it is grounded behind the back seats to one of the tie down area bolts. I will probably end up moving the ground and also re wiring the sub correctly. May just wait and run new amp wiring and rca cables. Should of known it wouldn't be as easy as just making some quick connections!
 
Does it go to protect as soon as it's turned on?
If you don't have a meter to check, try connecting only one coil and then the other to see if one only is shorted.
Loading it down, even if its not rated for 2 ohms will not result in protect when turned on. It will run but not too long before it thermals.
 
Thanks for all the info everyone. I had some down time while at work and had some tools available so I re wired the sub. Had the wires crossed on the left and right coils plus wired to run in series. Working good now just gotta decide where to mount the amp.

You guys rock at answering questions quickly and correctly with limited info. :guitar3:
 
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