How to Wire High Level Input on Amp

Audio amplifiers for cars come in many different configurations. One of the functions of an amplifier is to accept a signal from one source like your radio and improve the sound quality and speaker level input to give you a better listening experience.

Now, there are a few ways to make this happen and one of them is to connect more than one amplifier to get the desired outputs. Here’s how you can do that by using low and high-level inputs either exclusively or in combination.

If you are not sure about how to wire high-level input on an amp, here’s a look.

What Is a Wire High Level Input on Amp?

If you didn’t know it already, a high-level input is just another way of saying you will use the speaker wire lead behind the radio instead of RCA cables and connect them to the amplifier. This is how you get an input signal to the amp.

Now, a lot of factor radios don’t come with RCA jacks which makes it very difficult to install an amp in an audio system. So, manufacturers came up with a solution that requires you to use high-level input so that their products can be connected and played in the newer cars.

Now, we will tell you how to hook up an amp without RCA jacks but if you have a pair of them, it’s not a problem. Let’s take a look at the connections and how you need to wire them for the output you desire.

Which Type of Connection Do I Need?

Typically, factory audio systems that have high-level inputs do not sound nearly as good as low-level input connections. This is true even when you use aftermarket stereo systems.

But not many people pay attention to this because the output does not seem as different. They can even degrade the signal if the connections are not made properly.

This is also because high-level input systems need you to make changes to the wiring of the car. Instead, a lot of people just use RCA cables. This is not a bad way to go because, in the end, it does give you flexibility in terms of installation irrespective of the type of system you are dealing with. Here are the popular choices to wire high-level input on an amplifier.

1.     Use a Line Output Converter

A line output converter or an LOC has a high-voltage resistor and a transformer. It connects to the amplifier using an RCA patch cable. You need to ground the transformer of the device with LOC cables meant for this purpose.

The line output converter also has an RCA adapter for amp which connects to the stock radio and takes the speaker-level input signal coming in at high voltage and converts it into a preamp-level signal that brings it to an acceptable power range for the amplifier at hand.

A line output converter also has a feature that lets you adjust the gain so that the output is tweaked. This makes sure that the subwoofer is not overworked when it is balancing the output trim level of the amplifier.

If you want the amplifier to accept the high-level input directly, you can use a high-to-low converter and that is what an LOC is for. This is a popular choice because the connection uses RCA cables which provide an input signal directly to the amp.

Using a line output converter makes it easy to control the different signals coming in from various channels to the radio. Here’s how you can wire it.

  • Step 1: Disconnect the negative terminal of the battery to make sure there are no electrical problems like short circuits or blown fuses.
  • Step 2: You need to locate the wire that connects to the LOC. For this, you will need to take out the factory head unit. It is best to check out the user manual to be able to do this safely because you might have to remove a few screws to take off the panels.
  • Step 3: Take a look at the high input amp wiring diagram along with the diagram for the stereo output wires. Learn about the connections and the wiring on your LOC. This will make it easy for you to connect the wires to the corresponding terminals.
  • Step 4: Remove about an inch of the insulation of the LOC wire and the stereo wire. Now connect the LOC’s front left to the stereo wire’s side. And do the same with the front right wires too.
  • Step 5: Cover the connection with electrical tape and make sure the wires are secure together. Plug in the RCA cables from the LOC to the amplifier.
  • Step 6: Connect the battery, switch on the stereo and test the amplifier and speakers.

2.   Use RCA Cables

When you are dealing with a 4-channel amp and have chosen RCA cables to wire it, you will need to buy a second pair and an amp wiring kit, if you don’t have them already. Note that the kit is likely to have a cable for a 2-channel amp which you might need.

Before you start the process, make sure you have:

  • 100-feet speaker wire that is 18 gauge or more
  • Butt connector and crimp tool
  • Electrical tape
  • Cutting pliers
  • 6-inch wire ties
  • Testing meter

Typically, for these kinds of installations, you need to have 18’ cables. The idea is for the cable to be long enough to suit most cars. If the cable is longer than you need it to be, you can always hide it under the back seat or make a similar adjustment. But not much you can do if it is shorter. Now, for the process. Here’s how it goes.

  • Step 1: Connect the four RCA cables to the outputs in the front and the rear. If you are using a line-level converter, the same logic applies.
  • Step 2: The RCA cables sometimes have markings that tell you which is left and which is right. In some cables, the color of the cable is used to tell the difference, in which case, the cables in the lighter color or white are the left channel.
  • Step 3: Once you connect the RCA cables, you must mark them for future reference. Place a tape on one of them or use a marker.

And you are good to go. Switch on your radio and speakers and test out the amplifier.

Use Speaker Wire

Another way of wiring high-level input on an amplifier is to use the speaker wires. Using this method, you will be using the power coming from the harness of the factory radio to get an output from the speakers.

These wires are behind the radio which means you will have to remove them carefully to access them. Here’s how you connect them.

  • Step 1: Identify the wires that are meant for the speaker of your choice. Sometimes, you can tell the difference because the positive wires are in solid color and the negative ones have a stripe of another color on them.
  • Step 2: Cut the insulation of each wire to about an inch. Connect the wire from the radio to a wire that needs to go to the amplifier’s input end.
  • Step 3: Connect the wire that is connected to your speakers to the wire that is connected to the amplifier’s output.

Switch on the radio and speakers and test your amplifier.


Is It Better to Use High-Level Inputs on Amp?

A lot of amplifiers these days work well with high-level inputs in the 10-volt range. So, you can connect the speaker with the existing radio’s connections and plug it into the amp. This makes installation easy and gives you better output too.

What Is the Difference between High and Low Input on Amp?

High-level inputs come in handy if you want to connect a factory radio to an amplifier that doesn’t come with RCA connectors. This takes the signal from the speaker and sends it to the amp as the input.

Low-level inputs, on the other hand, use RCA cables to connect the audio source with an amp. Factory radios usually don’t have these inputs.

Do RCA Cables Go to Input or Output on Amp?

RCA cables usually go into the input socket of the amplifier. For this, you need to connect the red cable to the amp’s red input socket and you’re done. Play a track and see if the connections are in place.

What is a high level input?

A high level input is an audio signal coming from the outputs of an amplifier, preamp, or other source device. It typically has higher voltage and lower impedance than a low level input.

Can I use a subwoofer with speaker level inputs?

Yes, you can connect your subwoofer to speaker-level inputs as long as they are compatible with the type of signals that come from your main speakers. You will need to make sure you have the correct cables and connectors for this connection.

How do I wire speakers?

When wiring speakers, you’ll need to connect each speaker to its own set of positive and negative wires. This may require using both factory wiring or running new wires through walls or ceilings. Additionally, some components may require ground wire connections for safety reasons.

What are RCA connections used for?

RCA connections are typically used for connecting audio components such as amplifiers to receivers, TVs, CD players, etc.. They offer a balanced differential signal over two separate channels (left and right), allowing for clearer sound reproduction than traditional high/low inputs found on older equipment.

What is the difference between left and right speakers?

The left speaker produces audio signals that come from the left channel while the right speaker produces audio signals that come from the right channel. With stereo systems, having both a left and right speaker allows for more realistic sound that can provide a better listening experience.

How do I determine which speaker wire leads are positive and negative when connecting radio’s speaker wires to factory stereo?

To determine which speaker wire leads are positive and negative when connecting radio’s speaker wires to factory stereo, you’ll need to refer to the manual of your stereo system or car manufacturer. Generally, you’ll find red being used for positive terminals and black or white being used for negative terminals.

Where should I connect my remote turn on wire in a car stereo system?

The remote turn on wire should be connected to either an amplifier’s remote lead or a power antenna lead in order to remotely turn it on with your head unit. Be sure there is 12 volts present at this lead before making any connections as this will prevent damage to your equipment.

Which wires should I connect together if I want to ground my radio’s power wire?

If you want to ground your radio’s power wires, then you should connect them together with one of the ground wires found at the back of your head units output terminals. Make sure all connections have been made properly as loose grounds can cause interference in audio signals coming through your speakers.

What is high level input on an amp?

High level input on an amp is a type of wiring setup that involves connecting the amplifier directly to the speaker. This means it’s a direct signal from the speaker to the amplifier, bypassing any preamp or other components used in other types of setups.

How do you wire high level input on an amp?

Wiring up high level input on an amp requires connecting one end of a suitable cable to the terminals or tabs labeled “”Speaker Level Input”” on your amplifier and then connecting one end of the same cable to your speaker’s output terminal. Make sure not to connect anything to the “”Line Level Input”” if applicable, as this can cause damage to your equipment.

What is a high level input wiring diagram?

A high level input wiring diagram is used when configuring amplifiers for powering speakers directly through their outputs rather than using separate preamps or other components. Generally, these diagrams will show which wires are connected together at each step in order to get your system properly set up with minimal risk of damage or noise interference.

How do you hook up a high level input on an amp?

Hooking up a high level input on an amp requires connecting one end of a suitable cable to both the speaker output terminal and terminals or tabs labeled “Speaker Level Input” (or similar) on your amplifier. It’s important not to connect anything into “Line Level Input” (if applicable). Doing so may result in damage and/or noise interference due improper configuration.

What is a high input amp?

A high input amp, also known as a line-level input, is an amplifier that receives audio signals from sources such as CD players and digital music devices. These amps are specifically designed to handle higher levels of signal than standard speaker-level inputs and create improved sound quality.

What is the use of high level inputs on amp?

High level inputs on amps allow for improved signal processing and amplification. The benefits include increased power efficiency, reduced distortion, better sound quality, and minimized noise interference. This makes it ideal for connecting components like subwoofers or other speakers to an amplifier.

How do I connect a car amplifier with high level input?

To connect a car amplifier with high level input, you will need to identify the output terminals on your deck or source unit (head unit) and then connect them to the corresponding left/right RCA outputs on the amplifier. You will also need to ensure that your speaker wires are connected securely to your subwoofer before powering up the system.

What are the benefits of having a high level input car amplifier?

A high level input car amplifier offers several advantages over traditional amplifiers including improved signal processing, reduced distortion, better sound quality, increased power efficiency, and minimized noise interference. This makes it great for adding additional power to your audio system while minimizing potential audio problems along the way.

Wrapping Up

A lot of people like to leave the factory radio in place. But if you are looking for an upgrade that involves integrating an amplifier into the audio system so that your speakers have more power, you need preamp outputs that make the connections possible.

Many factory radios don’t come with these connections, so you need other ways to make it happen. Of the three options we have discussed in this piece, using an LOC is the most affordable.

Last Updated on November 7, 2023 by Brian Beasley

Written by Danny Reid

Hey, I'm Danny, and I know how hard it can be to find the perfect audio gear. Need a new stereo, amp, speakers, or subs? Don't worry – my blog is here to help you cut through the noise! My mission is to give you the best reviews, so you can make the right decision for your audio needs. And if you ever get stuck thinking, "Where does this blue wire go?" don't worry – I've got tons of cool tips to help you out of any jam. So come along with me on this fun, sound-filled adventure, and let's find the perfect audio setup to make your tunes really sing!