Best Line Out Converter-Review & Buying Guides 2021

An amplifier is an important tool for those who want more volume, depth, and detail to their tunes. With a powerful amplifier, you’ll be nodding your head along or dancing to your favorite music. But, amplifiers only work if one has a factory stereo. Unfortunately, these stereos don’t have preamp outputs necessary for hooking up an external amplifier. And that is where you seek the help of a line converter.

A line output converter (LOC) converts high levels amplified signals into low levels signals those that one can feed their amplifier with. Many people often connect this device to a stock head unit or an external amplifier. But you can also use it for connecting a new receiver to your car’s amplifier. However, since there are many LOCs available today, deciding which one is suitable for you can be difficult. That’s where we come in. We’ve researched and put together this list of the best line out converter.

Top 5 Best Line Out Converter

Best Line Out Converter

1. AudioControl LC2i Line Out Converter

AudioControl LC2i 2 Channel Line Out Converter

Topping our list is this LC2i 2 converter from AudioControl. This company offers excellent LOC models. For those who want a two-channel LOC, there’s no better option than AudioControl LC2i.

We love its active input circuitry. It also comes with 2 speaker input levels where one can connect amplified signals from an amplifier or installed radio as high as 400 watts per channel. Where this model excels is in pumping out pre-amp high-quality signals as high as 9.5 volts RMS. Individuals can feed these signals to an external sound processor or amplifier for better performance.

You’ll also love AccuBASS circuitry feature included in this device that corrects bass in case of a roll-off. Most factory speakers don’t produce clean and loud bass. As such, stock radios reduce bass with higher volumes so that the speakers aren’t destroyed. However, they don’t return it back when speakers are upgraded. And that’s where AccuBass comes in. Since it reverses bass roll-off, it gives perfect bass to enjoy your favorite songs. For better performance, we advise that you mount this LOC between the bass amplifier and your factory system.

Again, this product has excellent speaker level input which has signal sensing that senses incoming signals and then turns this LOC on. You’ll also appreciate 12 voltage lead output that signal amplifiers as well as other components to turn on once you’ve started your vehicle’s engine.

What We Like:

  • Installing is easy
  • Includes AccuBass Software for bass correction
  • Compact design
  • Features a single or double head units

What Could Be Better:

  • Some users have complained about its accessories

2. DS18 V5HL Line Out Converter

DS18 V5HL 5-Channel Line Out Converter

When it comes to car audio products and devices, DS18 doesn’t cut corners. This company manufactures subwoofers, speakers, audio processors, and amplifiers that are of high quality. So, we know that this LOC will not disappoint.

There are many impressive features you’ll love about DS18 V5HL. One is that being a 5 channel LOC, users can integrate their stock head unit with rear, front, and sub channels to their aftermarket system that’s powered by an external amplifier.

Car stereos often put out low signal levels forcing one to turn the gain up which can cause sound distortion. Fortunately, this LOC puts out 4- volts RCA low signal hence doesn’t burden your amplifier thus the signal-noise-ratio is significantly improved.

Installation is easy even in vehicles that have limited spaces. It also features a metal case that obstructs electromagnetic signals as well as ground noises. While there sure are better converters than this, the DS18 V5HL is still excellent for its price.

What We Like:

  • Ease of installation
  • Can be discreetly installed
  • Reasonably priced
  • Five channels that give users several options

What Could Be Better:

  • Running all channels simultaneously can cause slight interference
  • Can be noisy and hot when running


 SCOSCHE LOC2SL Car Stereo 2-Channel Audio Adjustable Amplifier

If you’re in search of an affordable LOC, look no further than this model right here. What we love about this 2 channel converter is that it allows tapping into wires of the stock speaker and sending signals as high as 4-volt to the preamp inputs on your mono amplifier.

It works well with high power car stereo speakers up to 80 watts per channel. It also features an impressive signal sensing feature that turns your amplifier on whenever there’s an incoming signal. Therefore, you don’t need a turn wire.

Where this product excels is that it comes with a remote control knob which is for adjusting bass levels without one moving from the front seat.

What We Like:

  • Limited free warranty
  • Comes with remote control
  • Reasonably priced
  • Installation is easy

What Could Be Better:

  • Needs a high power factory stereo
  • Lacks many extra features

4. JL AUDIO LoC-22 | 2 Kanal Line Out Converter High Low

 JL AUDIO LoC-22 | 2 Kanal Line Out Converter High Low


What do you expect from a line output converter? Simply conversion of the Speaker-Level Output to RCA Preamp Level Signal? Today, we come with one of our fabulous two-channel line-out converters. JL Audio LOC-22 is one of the best Line converters for a different purpose.

Once you connect this converter to the amp, to the speaker, and the subwoofer, it will give you a perfect performance throughout its whole lifespan. 

You can automatically control this unit’s volume on the sub-device using the volume knob. The auto knob presence on the amp will make you satisfied surely. This converter top is another level advantage, pushing the buyer to afford even a little more purchasing it.

The connection procedure is effortless. Once you follow the user manual and set this unit correctly on your audio system, it will work great, leaving no objection scope for you. Don’t panic with this Line out converter; you can easily do it to obtain a good result.

Whatever your intention to use this converter, whether you set it onto your pioneer amp or A4 B8 (on your B & O system)- JL AUDIO LoC-22 with its 2 Kanal Line Out Converter will provide you all High Low power conversion to meet your demand.

What We Like:

  • Simple connection procedure
  • Correct adjustment
  • Flawless working to connect the radio with the am

What Could Be Better:

  • Manufacturers should focus on the design of this LOC.

5. PAC SNI Line Out Converter

PAC LP7-2 L.O.C. PRO Series 2-Channel Line Output Converter

The last product on our list is this PAC SNI converter that comes with 2 channels which serve as an extra set of pre-amps for head units that only have 1 set. What we love most about this product is its wide frequency range of 20, 000HZ. But, we’re also impressed by the fact that each channel can handle 2-40W power. This converter is designed such that it can isolate input and output circles, hence prevents electromagnetic interference as well as ground loop noise. You don’t need an external source of power with this model as it is passive. Therefore, it doesn’t draw power from your car battery.

Those who are on a tight budget will also appreciate that it costs $8 only. Because of this cheap price, one may doubt its quality. But, considering how small and low powered this unit is, it is quite powerful. And even those who’ve not fixed a line out converter before will still have an easy time installing this model. If you want to add new life into your speakers with a powerful converter without hurting your wallet, this is an excellent model for you.

What We Like:

  • Pocket-friendly
  • Simple compact design
  • Includes separate knobs for each channel output level

What Could Be Better:

  • Material quality isn’t that great
  • Short-lived compared to other expensive models

Best Line out Converter Buyer’s Guide 

To choose the best line out converter for sub, you have to be aware of what a LOC is and how it works. Car system speakers mainly consist of three major components: the head unit or radio that controls this entire system and generates the first audio signal. There’s also an amplifier for increasing audio signal’s strength so that it’s strong enough to be moved into the speakers which are the third component.

Now, the head unit produces an audio signal. But, it can’t do anything since it’s weak. It, therefore, needs boosting by a preamp. After, this signal is fed into an amplifier that again boosts its strength. Since it’s strong enough, it is then passed to speakers that vibrate hence produce the sound you want.

Now, while speakers play an essential role in sound quality, what mainly affects a car’s stereo sound system is the amplifier. Stronger amplifies create stronger signals that cause loud and clear sounds.

But, most car factory stereos don’t make use of their amplifiers fully. That’s why line converters are used to convert the signal from a head unit into a better signal that drives preamps inputs in an amplifier. In simple terms, it’s a device that helps you fully utilize your car stereo system without replacing your head unit or amplifier. So, now that you’ve understood that, let’s look at the factors you should consider when buying a line out converter.

Input/ Output Channels

Input channels indicate the number of speaker levels output from a head unit a converter can be hooked to while output channels are how many amp’s channels a LOC can connect to. LOCs come in 2, 4, and 6 channels of configurations. Each channel powers a speaker. You should think of your audio plans now and in the future when deciding how many channels you need.

Output Levels

This simply measures how “hot” your speaker’s output signal is. To get the highest quality of sound, your converter should produce an undistorted signal without overloading your amp’s max gain. The input gain of sensitivity of your amp and your line converter’s output voltage should be almost similar. For example,  an amplifier that has a 5V max input gain sensitivity will work well with a LOC that’s set to a 5V output. If it’s higher, it can cause overheating and damage your amplifier. And if it’s lower, it’ll interfere with the quality of sound from your speaker.

Extra Features

Apart from converting speaker level signals, the best line out converter for sub also does other things. Most LOCs come fitted with several other tools that better the signal quality such as remote control, bass boost, EQ leveling, etc. Consider what other things a line converter can do for you before purchasing it.

Type of Line Converter

There are two styles of converters: passive and active. Passive line out converters are great for audio systems that are low powered and don’t have a factory amplifier. They reduce the voltage down from the speaker level to RCA low-level voltage. They offer 2 and 4 output channels and include the transistor basic technology. Active line out converters are advanced versions of passive converters that require an output signal of 12v. They take up to 400 Watts per channel hence can produce a better quality of sound. They have extra features like remote turn on, liner driver capabilities, bass restoration, etc. Only that they’re more expensive.

How We Picked the Best Line Out Converter for Subwoofer

As we’ve said above, certain features make a lineup converter great. And we considered these features when picking our top 5 LOCs. One area that we focused on is the ease of installing. While it’s best you have a professional installing this device for you, some LOCs, provided that you follow the instructions, you can install them yourself. We chose models that individuals can install on their own easily. However, it’ll be nice if you had an extra pair of hands.

Best Line Out Converter for Subwoofer

Also, we went with affordable line converters. LOCs can significantly boost your car sound system. However, you have to get a good model. But, many people often think that the pricier something is, the better its performance. While this is true, it is not always. Some converters are fairly priced and they still offer exemplary performance. However, we advise that you avoid purchasing the cheapest models. Most likely, they don’t offer good service. We picked some excellent models that will serve you well without denting your pocket.

Additionally, we went with models that had extra features. While the main function of a line out converter is to boost signals from a head unit, it can do more than that provided it has the proper features. For instance, some LOCs come with liner restoration features. These extra tools are what we looked at when picking these models. For instance, AudioControl LC2i comes with AccuBass to improve bass quality. Also, SCHOOSCHE LOC2SL comes with remote-control that allows one to easily adjust the bass level.

All You Need to Know about Line Out Converter

As we’ve earlier said, line up converters convert signals from a head unit into a preamp-level signal. As such, one can connect their radio to their amplifier. Now, these devices are essential if you want to boost your car’s stereo sound system. Note that many factory radios don’t have preamp outputs. But, even without replacing your factory radio, you can still upgrade your car’s sound system by tapping into wires of your speakers for audio signals. And you’ll need a LOC to provide these connections needed to add an amp.

Usually, one cuts their speaker wires, run them to the line converters, then run wires from their amp back to the cut wire’s other side such that signals are sent to your speakers. But, if an amp is added to power a subwoofer or additional speakers, all you’ll do is tap into your car’s stereo speaker to get the audio signals required to feed into the amp. So long as one is tapping speaker wires, they’ll always get audio from those speakers and their LOC will then get the signal needed for your amp to power the extra speakers.

Note that some LOCs are more pricey than others. That’s because they vary in features and power handling. It’s therefore wise that one knows how much power output goes into a line converter of their choice. RMS wattage is the maximum wattage that can go into most converters. When it comes to extra features some models have bass equalizers or circuitry. Others have a high preamp output voltage that keeps audio signals undistorted.

Now that we’ve understood what a line converter does, let’s briefly look at its construction. A converter that’s high powered has a high power resistor, usually 10 watts, and a transformer. A resistor is used for loading amplifier into a head unit while a transformer is for passing voltage difference between the available input terminals. Now, because a Direct Current voltage usually increases from time to time on both input terminals of the LOC, this cancels the DC’s pulse. This means, if LOCs used resistors as voltage dividers without a transformer, it would cause a severe turn on pop that could damage most amplifiers.

Important Q/A about Line Out Converter

How do line converters work?

Once you switch on your head unit, it produces an initial audio signal and this causes a spike in DC voltage. LOC resistor then loads this signal while the transformer distributes this voltage spike to ends of a LOC causing a simultaneous increase in voltage and they cancel each other out. This whole process thus causes an increase in the signal quality and blocks any DC pulses from a head unit from reaching your amplifier hence sound quality isn’t affected. Most line out converters come with extra wires that are for shielding output cables to the head units, as such, one can ground their LOC to any point of their vehicle without creating a ground loop.

Which LOC should I choose?

Well, there are two types of LOC; external and internal. When choosing, one should decide what they want to achieve. For instance, someone who wants to future-proof their car sound system should opt for an external LOC over an amplifier that has speaker levels inputs.

How do I wire a LOC?

This is a pretty straightforward process. You’ll only hook up your speaker output levels to the LOC’s input and that’s it.

Does my amplifier need a line out converter?

Not all aftermarket amplifiers require a LOC. Some already have speaker levels input, that lets one connect their speaker wires directly hence you won’t need a line out converter. Note that the amplifiers ensure speaker-to-line conversion. Even subwoofers can do this too.

However, most amplifiers don’t have speaker level inputs, that’s why people use LOCs with stock equipment. These devices come with many features and functionality that’s not in amplifiers. For instance, active LOCs have bass restoration, onboard equalizers, etc. which ensures that your sound is precise.

Can a LOC damage my stereo?

Yes, but only if you don’t install it correctly or set it to the wrong levels. For example, if someone reverses the lead’s polarity when connecting their LOC, this can cause a reverse current that may harm your system. Also, if your amp’s gain output is higher than its max gain input, it can damage your speakers and amp. But so long as things are set correctly, a LOC shouldn’t damage your stereo system.

Do I need an external power source for my converter?

Well, that depends on which converter you have. Passive LOCs don’t need an external power source since all they do is modulate voltage which doesn’t need monitoring actively. But if you have an active converter, you’ll need an external source of power that’s at least 12v. In most cases, they draw power from your car battery. But, because they only do this when receiving a signal, which means if you leave them connected they shouldn’t drain your battery.

Final Thoughts

Even if you are working with a head unit that has no RCA outputs, don’t feel left out. You can simply add some amplification to your subwoofer or speakers by using a line out converter. However, picking a suitable LOC can be difficult as you have to sift through different available options.

Our list contains all common types of amplifiers including cheap as well as high-end models that meet any budget size. We hope that this product review helped you find an excellent line LOC fit for your car stereo speaker system. A good line out converter best buy for you is one that’ll bring all the highs and lows and improve your audio experience.

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