Amp protect mode is built to guard the device against electrical harm. So, if the safety system is turned on automatically, you are good to go (at least when it comes to safety). But you still may be wondering, “why is my car amplifier staying in protection mode.”
Well, the thing is, there may be something wrong with the amplifier itself, the connected devices, or the cable lines. Although mostly it’s due to an overheating or overloading problem, you can’t ignore other possibilities.
Whatever the problem source is, immediate fixing is compulsory. If not, the whole sound system will be damaged soon.
This technical post is a complete guide to finding out why the amp is stuck in the protect mode and how to fix it.
Car Protection Mode – How Does This Work?
Your car amp protection mode is designed to protect the device from malfunctioning damages such as over-voltage, overcurrent, and short circuits.
When your amp is in protection mode, it’ll not allow any power to flow through the unit. This is important because if any of the issues cause damage to your amp, it can also harm other integrated devices and components like the subwoofer.
The protection mode features three main types of protection: current, voltage, and power.
Firstly, the current protection reduces the amount of current being sent through the amp from external units when overloaded.
Voltage protection allows the amp to decrease the excessive volt rate flow when identified.
And lastly, power protection ensures safety against short circuit-related issues.
“As protection mode doesn’t cut the amp power completely, it’s also called sleep mode.”
How to Find If Your Amp Is in the Protection Mode?
People often get confused about whether their amp isn’t working due to the protection mode or it’s permanently damaged. However, you can immediately identify when it enters the protection mode.
The identification part may vary depending on your amp brand. But in most car amps, there is a “PRT” label to identify the feature status.
In some car amplifiers, you would find blue LED lights, which blink when it turns the feature on. For example, Rockford Fosgate amps have similar indicator lights to show the protect mode status.
Some car brands, such as Kicker, have red LED lights. It powers the light on when switching to the mode.
Carvin and Boss car amps have a single green light, which indicates both power and protect mode for the same purpose. However, when it enters sleep mode, the light starts blinking.
Without the lights, you can also recognize the protect mode on the digital display if your amp has one. It appears when the mode is turned on.
What Causes Your Car Amplifier to Switch to Protection Mode?
The amp protection mode may turn on because of one or multiple reasons. Identifying the reason asap may reduce the chance of unwanted damages, which can be any of the below:
- Over or underflow of the vehicle’s battery voltage
- The inconsistent audio frequency level
- Excessive power flow, causing overload for the amp
- Malfunction in input signal frequency coming from the head unit and receiver (often happens when RCA cable is worn away)
- Overheating, which is caused by lack of ventilation or mismatch of amp and speaker box load capacity
- Circuit failure in the amp and the speakers connecting the power cable
- Mismatch of the speakers’ impedance and the amp’s power level
How to Solve a Car Amplifier Protection Mode Problem?
There are many ways to get an amp out of protection mode. Although I’ve mentioned multiple problems, some of them are sourced in a single component. And fixing or replacing the part can solve the issue. Go through each solution given below to find yours.
Solution 1: Fixing the Battery Voltage Issue
Check the battery if you doubt the problem is with the improper flow of car battery voltage. Look for if there’s any physical damage like corrosion or rust. If there are no external physical damages, you need to check the voltage level. Use a voltmeter for this purpose.
Most car battery voltages should be between 12.4 and 12.7 volts. If the battery voltage shows below a 12.4 rating, the charging system may not be functioning properly.
Check the alternator and all its associated wiring, fuses, and circuit breakers. If any of the components of the charging system are worn out, damaged, or faulty, replace them with new parts.
However, if the charging system components are all in good condition, try charging the battery with a new charger. It’s supposed to bring the voltage back up to a healthy level.
And lastly, if the voltage is still not within the normal operating range, the battery may be defective and should be replaced.
Solution 2: Repairing the Transistor
The most common issue behind overloading or overheating is a faulty transistor, which eventually turns on the protection mode. If you also have the same issue, this quick repair may help. You’ll need a set of soldering toolkits to continue, including an in-circuit transistor tester and multimeter.
“If the problem is centered in the transistor, it requires technical knowledge to repair the problem. I don’t suggest you follow this step if you’re new in this field. It’s better to take the amp to the service center.”
Step 1: Test Base Controller and Emitter
First, you’ve to inspect the conduction level rating of the base-emitter controller and connected components. Use a multimeter with a 2000-ohm setting. Any of the readings shouldn’t be more than 0.7 volts for both the base emitter and collector.
“There are 2 types of transistors – output and input. You’ve to work on the output transistor as it causes the protection mode to stay on.”
Step 2: Unsolder the Leads
Disconnect the amp from the power line. Open the amp board. There are 3 leads on both sides of the board, using which you need to create a different circuit (assuming the circuit has blown).
You can make a 2-side connection for a single combination to create all required circuits.
Next, you need to remove the leads’ heads. These are glued to the PCB or printed circuit board. Remove them using pliers.
Start the unsoldering process now. To avoid excessive heating, unsolder a single lead on one side. Then switch to the other side.
“When doing unsoldering, you may accidentally detach the thermal compound or mica washer. Don’t worry; it happens even in the case of professional handling. You need to get the replacement if witnessing any damage.”
Step 3: Adjust the Quiescent
In this last phase, adjusting the bias current is important. It’s also called Quiescent. To do so, regulate the preset potentiometer placed beside your transistor driver.
Ensure matching the level of Quiescent to other channels to avoid unwanted distortion.
Solution 3: Fixing Head Unit Wire
When your amp experience overloading, the wires connected to the head unit may get damaged. Hence, wire failure is also possible for a new amp. A notable fact, if the issue is related to the head unit, your amplifier goes into the protect mode only if the radio is on.
“Head unit wire failure turns on the protection mode of an amp to save it from potential harm. Upon fixing the issue, the amp automatically switches off the mode and functions normally.”
The first step to fixing the wiring issue is identifying the problem’s source. Two types of wire may cause the consequence: remote wire and power cable.
Find and inspect the remote wire first. Check if there’s any damage or loss of connection. If you can’t find any issue, next, examine the main cable.
Car amps’ power cables have a direct connection with the vehicle battery. Therefore, these are supposed to show voltage ratings. Test the voltage of the cable.
If you find an excessive voltage rating, check for the power socket if it’s okay. In any way, you may need to change the cable.
And if none of them are showing any doubtable signs, the possible culprit is the ground cable. It’s because a broken ground cable can turn off the power mode and switch it to protect mode.
You can also try changing or repairing the RCA patch cable when there’s no other issue found.
“Overheating also occurs if there’s a wrong remote power on setup, which is caused by incorrect connection between the unit’s antenna and cable.”
Solution 4: Creating a Ventilation System
The above overheating issue typically happens when your amp becomes older. However, sometimes the problem is located in the amplifier itself.
An inadequate ventilation system is such a kind. It occurs when you play the amplifier for a long time, causing the device to heat up. The relief is it only happens to cheap amps.
In any case, if the overheating is caused by warm air, you can create an external ventilation system to drive the air out. You can mount a cooling fan in front of the amp hole where the air breaths out. It’ll work like a typical exhaust fan.
There could be some other reasons the default ventilation system couldn’t support enough to cool down the amplifier.
For example, internal overheating may also happen due to the old cable of the device. In that case, you need to patch the damaged part with electric tape.
Also, sometimes, any mistake during installation can cause an issue. In that case, you should disconnect the line, open the amp, and reinstall it. I also suggest checking the feature of the amp and connected speakers. Make sure all the compatibility features of the amp and speakers are fine-tuned.
Solution 5: Ensuring Proper Input Power Flow
When the system loads an inadequate amount of power from your car batteries than what the amp actually needs, it’ll switch on protection mode. And it’s applicable for both low and high power loads.
Though the problem mostly appears when installing new amplifiers, it’s also not rare in old amps.
To continue with the fixing, measure the compatibility first. Therefore, check the amp’s power outlet’s voltage rating using a multimeter.
A car amplifier features 12 volts. If the voltage rating you find is more or less than 12v, the device will switch to protect mode.
For low voltage ratings, the possible causes are damaged sockets and low-power car batteries.
On the other hand, if the rating is higher than usual, there could be a damaged cable line or other complex problems which require professional servicing.
“Talk to the amp shop if the problem is related to cable. Or else, consult with the car manufacturer team.”
Solution 6: Fixing Wrong Impedance Loads
If you can’t find the problem source by applying any of the above solutions, the only possible reason is a mismatch in the circuit’s impedance loads or the amp’s output power.
The amps and other connected units are built with separate circuits; however, because of the connection, these circuits functions following a correlation. Thus, all devices can transfer power loads or impedance when you turn on the amp.
Sometimes, the amp outgoing impendence towards subwoofers becomes lower than usual, which overwhelms the circuits.
And because of that, the amp’s watt level load increases. Because of that, the device witnesses excessive load, causing the protect mode to turn on.
In this case, modern amps themselves try the troubleshooting. These devices stop the power flow and switch to default or factory configuration. This process is just like solving the low impedance problem.
Things go wrong when the reset doesn’t fix the issue. In that case, you’ve to follow a manual approach, which is basically balancing the impedance level in all the woofers.
If you only got a single woofer, adjust the parameter of the woofer and the amp. For multiple woofers, you’ve to calculate the total required impedance and distribute it to all units.
“Follow the general law of Ohm for the calculation, which divides the unit volts by total current.”
After adjusting the impedance, it’s important to recheck the load of the devices. It allows you to learn if there’s a power shortage or surplus. Set the amplifier’s power load according to the rating you get from the inspection.
“The process is described considering you got enough knowledge in the field. It’s not recommended for non-technical persons.”
Why Does an Amp Go into Protect Mode When Bass Hits?
If your amplifier goes into protect mode when the bass hits, the possible reason behind the scene is too much power flow between it and the connected speakers.
To get an idea of what that means, you need to understand how the frequency flow works in and between the amp and the speakers.
The bass settings are directly connected to the frequency level your amp passes through. Increasing bass decrease the frequency level. And according to the backend configuration of amps, playing an amp while decreasing the frequency requires additional power.
Your amp’s loudness during low frequency requires more power load than when playing at a higher frequency.
And the amp mainly turns on the protection mode if it can’t handle the overpowering, overheating kind of stress. The same is noticeable in your case.
Your amp can’t provide a consistent low-frequency signal to the speakers. This happens when the amp power capacity is less than the connected speakers.
So, I’m assuming that the amp you got isn’t up to the mark to operate with the speakers. You can either change the amp or the speakers.
“For similar reasons, your speakers may deliver unpleasant distortion. It’ll be helpful to consult your amp’s manufacturer or a technician for help determining the cause of the problem.”
Why Does Amp Go into Protection Mode When Plugging in RCA?
If your amp goes into the protection only when the RCA plugs are hooked up, there could be a trickier problem.
In general, it happens when your device is getting DC voltage into the RCA input. Your head unit or the amp may be causing the problem.
To start fixing the issue, first, check the voltage rating using a meter. While testing, pick the DC settings. Set the level to the max, which is typically 30 volts.
Ground the black lead of the meter to the chassis of your car. A power terminal is also a suitable grounding option.
Then disconnect the RCA cable while connecting the meter’s red lead to any internal area of the cable. You may see the changes in the voltage reading on the meter if there’s any flow.
Next, do the same on the external area of the RCA cable. According to the problem, the rate is supposed to be nearly “0”.
Because even these portions of the RCA cable show only millivolts, this will drive the amp to protection mode. In that case, you should send the head unit for repairs.
“Some head units come with open ground fuse (surface mounted) to connect with the RCA cables. These are a bit tiny. Therefore, it is challenging to find them on the circuit board. “
If you can’t find any voltage-related issue with the cable, test the amp next. To proceed, connect the meter leads to the RCA jack of the amp. While doing this test, avoid contacting the lead to the amp’s chassis.
The amp voltage reading is supposed to appear on the meter. If there’s no issue with the jack, eject the lead and connect it to RCA ground. Inspect the positive reading now.
Upon finding the voltage reading here, you’ve to send the device to a nearby repair shop. Let them know about your finding.
How to Perform Reset of Your Car Amp When Stuck in the Protection Mode?
Performing a reset of your car amp sometimes resolves the protection mode problem. Depending on the amp type you got, the reset process can be different.
Note that if you reset the amp, you’ll lose all the internal memory data. However, the factory settings remain the same. For your convenience, I’ve shared a common reset guide below.
- Turn off your car amp and engine.
- Detach all the connections between the amp and the related devices and cables.
- Search for the amp’s positive (+) post terminal. It’s located in your car batteries, connecting with a red wire.
- Next, remove all the bolts of the outlet using a wrench. Unplug the wire from the outlet.
- Keep it disconnected for 30 seconds.
- Again, connect the plug, which may cause a little spark. However, it happens when the wire contacts the power flow.
If you have traditional amp technology, you may need to keep the plug off for a few hours. It’s common mainly in Skar amplifiers.
I also recommend taking the amp to a service center if the reset function isn’t working. Sometimes, it happens when there’s an issue with PCB.
Frequently Asked Questions
1. Why does my amp turn on the protect mode when cold?
If your car amp is stuck in the protection mode when it’s too cold outside, there could be a faulty part that becomes sensitive to thermal. Because of that, the amp circuit can’t pass the power flow. However, to exactly locate the problem, you can use a penetrant spray.
Spray the liquid on the amp’s circuit board and wire. If any part of the amp becomes sensitive to thermal, it’ll show the damaged spot. Afterward, send the unit to a technician.
2. Can poor grounding cause amps to get stuck in the protect mode?
Yes, a bad grounding of the amp eventually turns the protection mode on and keeps it still. Because of the incorrect grounding, your amplifier can’t maintain a consistent electrical flow.
3. Is remote wire switching my amp protect mode?
The remote wire is directly connected to the head unit. And when it’s broken or damaged, it’ll switch the amp to the protect mode.
4. Why my amp makes a popping sound and switch to protect mode?
If your amplifier makes a popping sound and switches to the protection mode, the problem is sourced in your speakers. However, disconnect all the connected speakers to confirm it and check if it makes the same sound. If it doesn’t, you can assume the speakers’ load capacity isn’t adequate for the amp.
Hopefully, the above-detailed guide gives the solution to the question you’ve come up with – why is my car amplifier staying in protection mode? There can be one or multiple reasons why your car amplifier is staying in protection mode.
In some cases, you can get an amp out of protection mode without any technical expertise. However, most of them need professional handling. So, it’s wise to take the device to a service center as soon as you encounter the problem.