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How to Get Your Amp Out of Protection Mode

Every now and then We get e-mails from readers who are looking for help to determine possible problems with their amps. One recent one asked, “How can I get my amplifier out of protection mode?”.

Well, to get your amplifier out of protection mode you need to figure out and isolate the problem that triggered “protect mode” in the first place.

Amplifiers go into protect mode for several reasons, and figuring out the exact cause requires some troubleshooting to determine where the problem might lie and to prevent that from happening again.

What is protect mode?

Power transistors, being semiconductor devices (used to amplify or switch electronic signals and electrical power), cost an arm and a leg to replace. They’re the priciest component of an amplifier, and if they fail by going short for some reason, then essentially you have a dead amplifier that is worthless. Additionally, your car speakers, especially brand-names ones are also quite expensive and a high-voltage through their voice coil can easily blow them out and render them non-operational. Therefore, it is vital for an amplifier to have some form of protection mechanism to protect these pricey components.

For these reasons and many more, most modern car amplifiers feature protection circuitry for thermal overload, over- or under-voltage, and short circuits. When any of the protection circuits engage, the amp automatically shuts down and goes into protection mode until the problem is corrected.

Essentially, the amplifier protect mode is a shutdown state that modern amplifiers go into under a number of different circumstances. It’s designed to prevent your amp from destroying itself.

Randomly or constantly going into protect mode is a tale-tell sign that something is wrong with your car audio system. So, while dealing with an amplifier in protect mode may be annoying, it might actually save you from a much bigger headache down the road.

If your amp has a “protect” light, and it’s on, then chances are good that:

  • The amp wasn’t properly installed
  • The amp is overheated
  • The amp is overtaxed – low impedance load
  • Improper wire gauge size was used
  • Loose wire(s)

How to recognize an amp in protect mode

Well, it depends on the amplifier, since not all amps are built the same. So, the boring but practical answer is to read your amp’s owner’s manual. If you lost it, just google it using your amp model number.

Car amplifier manuals contain a myriad of mind-boggling information, so if you’re overwhelmed, here are the main things to look for:

  • Whether there is a protect mode LED(s) indicator on the top of the amp
  • If the protect mode LED blinks in code to tell you what the problem is
  • If the protect mode LED changes its color to tell you what the problem is

Most car amplifier – if not all of them – have a power on LED that will let you know when the amp is up and running. It will usually be green but can be other colors. Check your owner’s manual to know for sure. Some LEDs will turn orange or red when something is wrong. Modern amps also have a “protect” on LED that turns red when the amplifier goes into protect mode.

Why is my amp in protection mode?

As we’ve mentioned above, car amplifiers go into protect mode for a numbers reasons. Here are a some of the most common.

  • Overtaxed amplifier (load mismatch): A car amplifier will put out different amounts of wattage based on the impedance load it’s presented with. Hooking up a 2-ohm subwoofer to a 4-ohm amplifier will put a lot of strain on the amplifier, overwhelm its circuits, triggering protect mode.

 

  • Overheating (thermal overload): An amplifier mounted underneath the seats, or in another confined space will easily overheat because of lack of airflow. If your amplifier gets too hot, it will go into protect mode to keep its internal components from melting.

 

  • Faulty component: A faulty component can trigger protect mode in a connected amplifier. For example, if a speaker’s wire shorts out, or if you plug an amp into a faulty headunit, the amp might shut down to prevent the problem from spreading.

 

Troubleshooting amplifier protect mode

Well, the easiest way is to think back to exactly what happened right before your amp went into protect mode.

1. Amplifier went into protect mode when it was turned on for the first time:

  • There was an installation problem
  • The remote turn-on wire doesn’t have power
  • The amp is wired incorrectly
  • Loose speaker wire
  • Faulty speaker, subwoofer, cable or another component
  • Blown fuse
  • Improper gauge wire
  • The power wire is loose, corroded, or shorted out somewhere
  • Poor ground connection
  • The amplifier isn’t isolated from bare metal contact with your vehicle
  • The amp is busted

2. Amplifier went into protect mode after an exceptionally long listening session:

  • The amp got too hot/overheated
  • Lack of airflow – Amp mounted underneath the seats, or in another confined space
  • Amplifier was overloaded – Ex: a 1-ohm speaker hooked up to a 4-ohm amplifier

3. Amplifier went into protect mode when you were driving on a rough road:

  • The wires weren’t secured tightly
  • Loose or shorted wire
  • Speaker connections in contact with bare metal

How to get your amp out of protection mode

To get your amplifier out of protection mode and prevent it from going into again down the line, you need figure out what caused it in the first place.

1. Unplug the speakers

The very first thing to do is to get the amplifier down to it’s most basic state. Disconnect all of the speaker wiring and RCA wiring and leave only the power, ground and remote leads connected, and then turn the amp back on and see if it’s still in protect mode. If you notice that the protect mode light turns off at that point, it’s a pretty safe bet that one of your speakers is blown.

Next, visually inspect your speakers one by one. If you notice that one of them is blown, or is grounded to the chassis of the vehicle, your amplifier will still try to put power to it. When it does, it “sees” a condition that makes it get overheat quickly and eventually shut down.

Use a multimeter to check your speaker’s electrical response. If the voltage is less than 12V with the engine on, then there’s a good chance the speaker is damaged.

To double check, set the meter to ohms, and touch the lead of the multimeter to the speaker terminals. If the multi-meter is reading 1.0 ohms, the speaker is not blown. A completely blown speaker will have infinite impedance.

Additionally, check the voltage across the plus (+) and negative (-) terminals with a multimeter. It should be about the same as what the battery reads when you check across the battery plus (+) and negative (-) terminals.

2. Unplug the headunit

Disconnect the headunit from the amplifier and try turning the amp on. If it starts normally, then there’s a good chance that either the headunit or the wiring is the culprit.

3. Check if your amp is hot

Amplifiers can get very hot and shutdown for a number of reasons. Four of the most common are: Blown/grounded speaker(s), poor power and/or ground connections, too low impedance load, or Gain/Punch Bass control settings too high.

Additionally, mounting your amp in a confined space such as under the seats will make the amplifier overheat because of lack of airflow.

That said, consider increasing the air gap between the top, bottom, and sides of the amp to help increase airflow. Moving your amp to a well-aired location can also help with overheating problems.

If you’ve fixed all the problems that can make an amp overheat, but you can’t seem to stop your amp from overheating, you can opt for a cooling fan; this will blow the heat away from your amplifier keeping it running as it should.

4. Check cables, terminals, and fuses

It goes without saying that all cables should be secured tightly. If your amplifier went into protect mode right after you installed it, you’ll want to start by checking the power and ground wires in addition to the patch cables. You’ll also want to check for any inline fuses and verify that none of the wires is loose, corroded, or shorted out somewhere.

5. Make sure you have a good ground connection

Using the right power and ground cables is as important as choosing the right car amplifier. To operate efficiently, an amplifier needs its power and ground wiring to be large enough to accommodate its demand for electrical current.

That said, if your power or ground cables are too small for your amp, then there’s a good chance the amp will go into protect mode when bass hits hard.  You may also experience thermal shutdown because the amplifier isn’t getting the power it needs to make the output you want.

As a general recommendation, follow the guidelines in the chart below as a quick reference in determining the appropriate wire gauge.

Wire Gauge SizeTotal Amplifier RMS Wattage
0/1 AWG1000+ Watts
4 AWG400-1000 Watts
8 AWG200-400 Watts
10 AWG100-200 Watts

Furthermore, if your amplifier ground connection is poor, or if it’s loose, your amp may fail to turn on or not function properly. The best and most efficient ground connection is when the wire is touching sanded or bare metal. You do not want the ground wire touching paint or any preexisting nut or bolt.

6. Properly set your amp’s gain

In an amplified car audio system, setting your amp’s gain correctly is crucial in order to enjoy your music’s impact better and hear exciting details and notes clearly, whether loud or soft.

If you don’t know what does gain mean and what does it do on an amp, refer to this article where we explain all of this in detail.

Essentially, the purpose of the gain control is to level match an amplifier’s input to the receiver’s output. Properly setting the gain reduces background noise, and prevents an amp from “clipping,”.

Incorrectly setting your amp’s gain isn’t a direct cause of amp going into protect mode. However, it can lead to all sorts of problems you can think of including but not limited to distortion, background noise, overheating, speaker damage …etc, which in turn can make an amplifier to go into protect mode.

7. Check the impedance load on your amp

One of the most common problems we’ve come across multiple times is wiring two 4-Ohm woofers in parallel for a 2-Ohm load, then bridging the amplifier to that load – but the amp is designed for 4-Ohms, not 2-Ohms. What happens in this case is that the amplifier “sees” a very low impedance – that’s lower than what the amplifier manufacturer recommends – and tries to keep up with it, but heats up fast due to the extra power it’s trying to pump out. Once it gets too hot, it shuts down and goes into protection mode.

Having said that, If you have a subwoofer or multiple subs in your system, make sure their overall impedance load is within the capability of your amplifier.

8. Replace faulty output transistors

Blown output transistors are considered to be one of the most common failure in amplifiers and are also the most common cause of an amplifier going into protect mode.

If your amp goes into protect with no RCA or speaker cables hooked up to it or if the amplifier keeps blowing the fuse right after the remote turn on wire is connected, it’s highly likely that your amp has shorted output transistors.

Replacing faulty output transistors is an easy job for the most part. It’s also relatively inexpensive. You can expect to pay between $50 and $100 for amplifiers up to ~150 watts/channel. However, costs add up significantly depending on how large the amp is.

Because large amplifiers use more transistors, you can expect the repairing to cost a pretty penny.

P.S: Generally speaking, repairing an amplifier is a highly technical subject, and definitely best left to a pro.

 

How to bypass protection mode on amp

If by “bypass” you mean to keep using the amp although it’s still in protect mode, we’re afraid there isn’t a way (at least to our knowledge).

Even if there were a way to bypass the protect mode, we wouldn’t recommend it, simply because this mode – as we’ve mentioned above – is there for a reason,  and that is to protect your equipment from damage until the problem that triggered it is sorted out.

Final Thoughts

All in all, if you’ve tried all the tips we listed here and none of them seems to be helping you in getting the amp out of protect mode, you’ll want make sure that the latter is physically isolated from any bare metal contact with the vehicle. Since metal components of a vehicle’s body all act as a ground, allowing your amp to touch bare metal can cause all sorts of problems.

If your amplifier doesn’t seem to be working after going through all the tips listed above, it may need a trip to the repair shop. If it’s under warranty then make sure you follow the proper procedure set by the manufacturer. Call the manufacturer if you’re not sure.

Alex Brown

Hey There, my name is Alex Brown, I'm an LA-based sound engineer with over 10 years experience installing, troubleshooting, and repairing commercial, automotive, and household sound equipment. I've installed highly competitive car audio systems, and everything from navigation systems to full car stereo systems, remote starters, alarms and beyond. I enjoy creating solutions and simplifying everyday needs. I also love helping people get great sounding gear, thereby, saving the world from bad sound one customer at a time.

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