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Best Line Output Converters

If you want to add more volume, more depth and detail to your tunes, amplifiers are definitely part of the picture. This is especially true if you still have the factory stereo.

A power amplifier will breathe life into your music, bringing out all of its excitement and detail. But factory stereos don’t have the preamp outputs needed to hook up an external amplifier. That’s when a line output converter comes into play. But which one to choose? Which one is the best for your needs?

To answer that, we have put together this resource, a one-stop-shop, all inclusive guide to help you find the best line out converter that meets your needs and fits within your budget.

What is a line output converter?

A line output converter, or LOC for short, is a device that converts speaker-level output signals (high-level amplified signals) into RCA preamp-level signals (low level signals); those that you can actually feed an amplifier with.

A line output converter is most often used to connect a stock headunit to an aftermarket external amplifier. However, It can also be used to connect a new receiver to a car’s factory amplifier.

Best Line Out Converters — Reviews

1. AudioControl LC2i 

AudioControl LC2i

  • Two channels – Accept 400 watt signals per channel
  • Fixed and variable outputs with discrete level controls
  • AccuBASS® processing for correction of bass roll-off
  • GTOTM Signal Sensing
  • Input For Optional Remote Level Control
  • Compact design

Last update on 2021-01-02 / Affiliate links / Images from Amazon Product Advertising API

AudioControl offers some of the best line output converters in the market. Their lineup of LOC seem to hit the sweet spot for a lot of guys, for good reason.

If you’re looking for a two channel line output converter, we can’t think of a better option than AudioControl LC2i. It’s one of the top-rated line output converters out there.

The LC2i, is a compact line output converter with active input circuitry. It features two speaker-level inputs that let you connect amplified signals up to 400 watts per channel from factory-installed radio or amplifier. The LC2i then pumps out high-quality pre-amp signals — up to 9.5 volts RMS — that can be fed to an external amplifier(or sound processor) and allows it to perform to its maximum ability while maintaining the use of factory volume and steering wheel controls.

The AudioControl LC2i is featured with AccuBASS® circuitry for correction of bass roll-of. In plain English, most factory speakers are nothing to write home about when it comes to loud, and clean bass reproduction. This is the reason why stock radios dial down the bass when the volume is turned up to protect the speakers. The problem is that they don’t give it back when the speakers are upgraded to powerful aftermarket ones. This is where AccuBASS comes into play, as it reverses the factory bass rolloff, giving you the bass you need to enjoy your music to the fullest.

Having said that, mount the LC2i between your factory system and your bass amplifier, and it’ll make a night and day difference in terms of bass response.

Additionally, this LOC’s speaker-level inputs have signal-sensing turn on feature which senses incoming signals and turns on the LC2i. There’s also a 12-volt turn-on lead output which tells your amps or other components to turn on when your car’s engine is started.

2. DS18 V5HL


  • Remote trigger output with built-in audio sensing technology
  • Clipping LED indicator
  • Signal to Noise Ratio: >95dB
  • 2.5V RCA Low Level Output

Last update on 2021-01-02 / Affiliate links / Images from Amazon Product Advertising API

DS18 is a pretty big name in the car audio industry. The company has offers everything from speakers and subwoofers to amplifiers and audio processors and maintains a level of quality throughout. The same goes for its selection of line output converters.

The V5HL is one of the best line out converter that DS18 has to offer. This 5 channel LOC is designed to let you integrate your stock headunit with front, rear, and sub channels directly to your aftermarket system powered by a powerful external amplifier.

Most car stereos put out 2.4V (or less) low level signal, which requires you to turn the gain up more, thereby causing more distortion. The DS18 V5HL puts out 4V low signal for RCA, lifting a burden off your amplifier, and improving the S/N ratio (Signal-to-noise ratio).

The V5HL is featured with built-in LED clipping indicators, which allow for easy gain adjustment that maximizes your head unit signal for high-quality audio reproduction.

This line out converter sports a compact footprint for ease of installation in space-challenged vehicles. It has a metal case which creates a shield from ground noises and electromagnetic signals.

Sure, there are better line out converters out there, but the DS18 V5HL is a great bang for the buck. It’s offers a solid, clean 4V low level signal, and subsequently bring out premium sound without distortion.

3. AudioControl LC7i

There are times when you want to eschew the cheap line output converters and go with something that offers the very best performance and list of features in a single package. And that’s precisely when the AudioControl LC2i is such a desirable option.

That said, if you’re looking to scale up from the AudioControl LC2i (mentioned above), AudioControl has a few of other choices available. One of the more popular options available is the LC7i.

AudioControl LC7i is a 6 channel active line converter. It’s designed to deliver impressive sound quality and fix one of the biggest weak points of today’s factory systems, weak BASS!

The LC7i can handle up to 400 watts per channel. It features 6 RCA preamp outputs (up to 8.5 volts) that’ll handle a traditional front/rear/sub setup.

The biggest thing with the LC7i in addition to its AccuBASS™ circuitry which restores the bass as the volume is turned up, is channel summing. This feature allows the AudioControl LC7i to sum together multiple input channels (4 or 6) from the factory source unit into 2 channels. It is typically most used when a factory system has multiple, actively crossed-over signals sent from the factory radio or amplifier(s). Summing feature allows you to sum those signals to create a full range output.

Level-matching with an LED indicator is another great feature of this line output converter. What it does is that it makes it a lot easier to match the output of your receiver to the amplifier’s input allowing for maximum performance and minimum noise from your system.

Furthermore, the LC7i’s comes equipped with a signal-sensing turn on features which sense incoming signals and turn on the LC7i. Its built-in 12-volt trigger on the other hand turns on your amps as well.

An optional ACR-1 dash remote control can be used with the LC7i allowing you to adjust the level of the low frequency output from the driver’s seat.

The LC7i has a compact chassis allowing for ease of installation in today’s space constrained vehicles.

4. PAC LP7-2


  • Built in remote turn-on circuit
  • Surface Mount Construction (SMT) for reliable and noise-free operation
  • Ultra-compact size for greater installation flexibility
  • Wire-tie or screw mounting provisions
  • Conservatively rated @ 55watts per channel

Last update on 2021-01-02 / Affiliate links / Images from Amazon Product Advertising API

If you’re on a budget and looking for something that can get the job done without breaking the bank, check out the PAC LP7-2. It’s not expensive, but you still get a lot for the money.

This super-compact line output converter was designed to be small enough to fit into some sort of nook and cranny in most vehicles allowing for greater installation flexibility.

The PAC LP7-2 is a two-channel line output converter rated at 55 watts per channel. It comes with a built in remote turn-on circuit and it’s configurable for speaker level or RCA level input/output.

The LP7-2 is also available in 4-Channel configuration. It’s really affordable because it’s not loaded with with any extra features compared to pricey models.

5. Kicker 46KISLOC2

Kicker 46KISLOC2

  • 2-channel line output converter
  • 12-volt DC output for amplifier remote turn-on
  • Accepts up to 55 watts RMS per channel
  • RCA line outputs up to 8 volts RMS

Last update on 2021-01-02 / Affiliate links / Images from Amazon Product Advertising API

Within the car audio space, Kicker is one of the renowned and trusted names. Out of all the brands in the car audio industry, none have set the standard the way kicker has. Kicker is generally viewed as one of the top companies in the space.

The 46KISLOC2 is one of the cheapest line output converters in the market. It has two channels and it can take as much as 50 watts RMS per channel and deliver up to 8 volts of output. It has a flat frequency response of 20Hz – 20kHz.

This little device delivers the the 12 volts required for activating outboard amps or processors. It generates this voltage using the input signals alone, with no external power source necessary.

Additionally, the 46KISLOC2 LOC has built-in load resistors, so it will work with factory radios with open-circuit protection.



  • Remote control know included
  • Works with high-powered car stereos (up to 80 watts per channel)

Last update on 2021-01-02 / Affiliate links / Images from Amazon Product Advertising API

This is another great, yet affordable line out converters. This 2-channel converter is designed to let let you tap into stock speaker wires to send up to a 4-volt signal to the preamp inputs on your 2-channel or mono amp.

SCOSCHE LOC2SL can handle up to 80 watts per channel. It has a built-in signal sensing turn-on feature, which allows it to turn on your amp when it senses an incoming signal, so there’s no need for a turn-on wire.

The LOC2SL is one of the fewest line out converters that come with a remote control knob for adjusting car subwoofer bass level from the front seat, making it one of the best line out converters for subwoofer that you can buy.

Things to consider in a line output converter

To choose the right line out converter you need to take a few things into account:

Input/output channels

The number of input channels on your line out converter refers to how many speaker level outputs from the headunit it can be hooked up to. The number of output channels on the other hand refers to the number of amp’s channels the LOC can connect to.

Line output converters come in 2 channel, 4 channel and 6 channel configurations. Each “channel” of a line output converter is a discrete way intended to power one speaker. How many channels you need depends on your plans for your audio system now and in the future.

Output levels

The output level of your line converter basically tells how “hot” the output signal is. Generally speaking, to get the best sound quality, you need to prevent your amp’s max gain input. To do that, your line output converter should send clean and undistorted signal to the amp. In other words, the output voltage of your line converter should be roughly the same as the max input gain of your amplifier.

That said, if your amp’s max input gain is 5V, then you your line converter must be set to a 5V output. If your LOC’s output level is higher than that of your amp’s gain input, the latter will overheat or get damaged. If it’s lower, you won’t get the full quality sound the speakers are capable of.

Extra features

High quality line output converter do not only convert speaker level signals into low level signals. They’re most often fitted with a bunch of tweaking tools to further enhance the quality of a signal, including bass boost, EQ leveling, channel summing, and remote turn-on.

Line Output Converters – FAQ

How do line output converters work?

What line output converters basically have a reduction transformer. So, they use a certain amount of windings for the inbound signal and a certain amount of windings for the outbound signal that creates a reduction in output voltage. So it takes our high-level speaker input and creates RCA low level output.

How can I hook up an amp to my car stereo that doesn’t have RCA preamp outputs?

Connecting an amplifier to a car headunit that doesn’t come with RCA preamp outputs is as easy as a pie. All you need to do is to connect the headunit’s speaker wires to the LOC’s inputs and use RCA cables to run the signal from the LOC to your amplifier.

Do stock headunits have preamp outputs?

This isn’t an extremely common thing. Most, if not all factory radios don’t come with preamp outputs, so using a line output converter is one of the best ways to add an amp without RCA jacks to your car audio system, unless, of course, you decide to replace your radio with an aftermarket one that has preamp outputs. Doing so is not always possible because of the radio’s look in the dash or the fact that you have a leased vehicle.

Still, you can upgrade your car audio system by tapping into the speaker wires for the audio signal. A line output converter provides the connectivity needed to do it in most cases.

A line output converter really comes into play any time you have a factory car radio that you want to leave in place for any reason.

Why are some line output converters expensive?

Pricey line output converters don’t only convert speaker-level output signal into RCA preamp-level signal, but also provide more features and power handling than cheaper ones. So, it’s important to know the total power output of the signal going into the line output converter you’re considering.

Most often, upgraded line output converters come equipped with higher preamp output voltages, which keeps the audio signal to your amp pure and ultra-clean. Others come equipped with bass restoration circuitry or equalizers on board too.

All in all, it all boils down to this: the more power a LOC can handle and the more tweaking tools it comes equipped with, the pricier it gets.

Do all amps require a line output converter?

No, not really. Not every aftermarket amplifier is going to require a line output converter.

Some amplifiers come equipped with speaker-level inputs, which let you connect your speaker wires directly, without needing a separate line output converter. The speaker-to-line level conversion is done within the amplifier. Most powered subwoofers (active subwoofers) offer this feature, too.

Would I ever want to use a line output converter over an amp with speaker-level inputs?

Well, it all depends on what you’re trying to achieve or build. As mentioned above, some advanced line output converters come loaded with a number of extra features that an amplifier you’re considering might not have, such as on-board equalizers, higher preamp output voltages, or restoration circuitry that resets the factory system’s equalizer to a flat setting. These additional features let you start from scratch in terms of setting up the sound the way you want it.

All in all, having a line output converter over an amp with speaker-level inputs can be an overkill, but it might also come in handy.

Will I need a line output converter to install a new stereo?

If you’re wanting to install a new headunit in a car with a separate factory amplifier, then you’ll definitely need a line output converter. The latter will be used in conjunction with vehicle-specific wiring adapters to make the new aftermarket receiver work with the factory amp.

Some high-end line output converters offer gain adjustments, so you can balance the output from your new aftermarket headunit to the input sensitivity of the factory amp for the optimal sound quality.

Why choose an external LOC over an internal LOC?

Well, it really depends on what you’re trying to achieve. If you want to future-proof your car audio system, then using an external LOC over an amp with speaker-level inputs might be a good idea.

The majority of line output converters that you can buy in the aftermarket have a flatter frequency response. Some of the higher-end line output converters have a load circuit.

That is essentially important in systems where you’re no longer going to use any of the factory amplification. Some factory amps and factory radios will have trouble when they see no load.

You can actually create a problem where you have speakers popping because the factory amp or the factory radio no longer sees a speaker. Luckily, using an external line output converter prevents that.

How do you wire a LOC?

Wiring a line output converter is pretty self-explanatory. All you need do is hook up the speaker level outputs to the input of the line output converter and you’re done.

Bottom Line

There’s no need to feel left out if you’re working with a factory headunit with no RCA outputs. Thanks to line output converters, you can still add some amplification to your speakers or add a subwoofer.

Finding the best line out converter for your needs can be challenging. Sifting through available options can be time consuming and stressful.

In the list above, we included everything from cheap line output converters all the way to high-end models and a few in-between to cater for all needs and budgets.

We also distilled the right specs to take into account before clicking that buy button.

We hope that we helped you narrow down your choices to a handful of options that are within your budget and can deliver on your expectations.

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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