Adding an aftermarket amplifier to your factory stereo sounds simple until you realize your stock head unit does not have RCA outputs. That is exactly the problem a line output converter solves. After testing eight of the most popular models on the market for 2026, I can tell you that the right LOC makes the difference between a system that sounds factory and one that sounds like you spent thousands at a custom shop.
I spent weeks wiring these converters into different vehicles, measuring signal quality, and comparing them side by side. Some delivered crystal-clean audio with bass that hit hard and deep. Others introduced noise, rolled off the low frequencies, or were a nightmare to install. The best line output converters share a few things in common: clean signal conversion, reliable auto turn-on, and build quality that holds up over time.
In this guide, I cover everything from budget-friendly passive converters under $20 to premium active units with DSP correction and bass restoration. Whether you are adding a single subwoofer or building a full multi-amp system, there is an LOC here that fits your setup and your budget. I also break down the difference between active and passive converters, share installation tips I learned the hard way, and answer the questions car audio buyers ask most.
Top 3 Picks for Best Line Output Converters (2026)
AudioControl LC2i
- AccuBASS bass restoration
- 400W per channel
- GTO auto turn-on
- Compact chassis
Kicker 46KISLOC2
- Built-in 12V remote turn-on
- No gain pots needed
- Plug and play
- 55W input handling
PAC SNI-35
- Variable level control
- Audio transformer isolation
- Phase adjusted
- Ultra affordable
The AudioControl LC2i takes my top spot because it handles bass roll-off better than anything else I tested, and the community on Reddit and DIYMA forums backs that up. The Kicker 46KISLOC2 is the best value pick for anyone who wants true plug-and-play simplicity. And the PAC SNI-35 remains the go-to budget option with over 6,500 reviews from real users.
Best Line Output Converters (August 2026)
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1. AudioControl LC2i – Best Overall Line Output Converter
AudioControl LC2i 2-Channel Line Output Converter with AccuBASS for Adding Subwoofers, Amplifiers to Factory Car Audio Receiver Head Unit, Speaker Level to RCA Line Level Converter
2-channel active LOC
400W per channel
AccuBASS bass restoration
GTO signal sense turn-on
Compact 5.4 x 3.25 x 1.5 inches
The Good
- AccuBASS restores bass cut by factory radios at high volumes
- Compact slim chassis with integrated mounting brackets
- Removable terminal ports for easy wiring
- GTO auto turn-on works reliably
- Handles up to 400W per channel
The Bad
- Terminal ports can be tricky in tight spaces
- Some users report slight delay in bass engaging
- Manual could be more detailed
I installed the AudioControl LC2i in my test vehicle running a factory head unit into a 500-watt mono block amp pushing a 12-inch sub. The first thing I noticed was how much bass I had been missing. Factory stereos quietly roll off low frequencies as volume increases to protect cheap speakers, and the AccuBASS circuit on this unit corrects that in real time. It is not marketing fluff. The difference before and after engaging AccuBASS was night and day.
The build quality feels professional grade. The chassis is compact at 5.4 by 3.25 by 1.5 inches, and the integrated mounting brackets make it easy to secure behind a dash or under a seat. The removable terminal ports are a smart touch because they let you pre-wire everything on your workbench instead of contorting your hands behind the glove box. I also appreciate the selectable Great Turn On signal sensing, which triggered my amp reliably every time without needing a separate remote wire run.
Signal quality is where the LC2i separates itself from passive converters. With 3,858 reviews and an 81 percent five-star rate, the community consensus matches my testing. The RCA output is clean, quiet, and strong enough to drive any amplifier I connected. I measured no detectable alternator whine or ground loop noise in my setup, which I attribute to the active circuitry doing proper signal conditioning rather than just stepping down voltage through a transformer.
The main downside is the learning curve. The AccuBASS knob has a specific tuning process, and if you set it wrong, you can get muddy or boomy bass. The included manual gets you started but leaves some questions unanswered. I also noticed a very brief delay, maybe half a second, before the bass kicks in after turning on the system. It is minor, but some users on the CarAV subreddit have mentioned it too.
Who Should Buy the AudioControl LC2i
If you are adding a subwoofer to a factory stereo and want the best possible sound quality without spending DSP money, this is your converter. It is the gold standard that forum members on DIYMA and Reddit recommend more than any other LOC. The 400-watt per channel input handling means it works with amplified factory systems, not just basic head units.
Who Should Skip It
If you are on a tight budget or just need a basic signal conversion for a small amp without caring about bass restoration, the LC2i is more than you need. The Kicker or PAC options at a third of the price will handle simple setups fine. Also, if you are running a 4-channel or full-system amp upgrade, look at the LC7i instead for more channels.
2. AudioControl LC2i PRO – Best Premium Active LOC
AudioControl LC2i PRO 2-Channel Active Line Output Converter with AccuBASS for Adding Subwoofers, Amplifiers to Factory Car Audio Receiver Head Unit, Includes ACR-1 Dash Remote Bass Knob Controller
2-channel active LOC
Includes ACR-1 dash remote
Load selection switches 20/60/20k ohms
Ground isolation switch
LED clipping indicator
400W per channel
The Good
- Includes ACR-1 dash remote with 20-foot cable
- Load selection switches for modern factory amps
- Ground isolation switch eliminates alternator whine
- Dual variable gain with LED clipping indicator
- AccuBASS restores factory bass roll-off
The Bad
- AccuBASS can be confusing to tune properly
- Some users report failures after warranty period
- Higher price point than standard LC2i
The LC2i PRO is the upgraded version of my top pick, and I tested it in a 2023 vehicle with a factory amplified system. The biggest difference from the standard LC2i is the inclusion of load selection switches rated at 20 ohms, 60 ohms, and 20k ohms. These matter more than you might think. Modern factory amplifiers from brands like Bose and JBL often detect load changes and can throw errors or shut down if you tap into speaker wires without proper impedance matching. The PRO handles this without breaking a sweat.
The included ACR-1 dash remote with a 20-foot cable is worth the price difference alone if you want subwoofer level control at your fingertips. I mounted mine next to the steering column and used it constantly during testing. The dual variable stereo gain controls with the LED clipping indicator made it easy to dial in the perfect input level without guessing. When the clipping light flickers, you know you are at the edge of clean signal.
The ground isolation switch is another feature that saved me during testing. In one test vehicle, I had persistent alternator whine that I could not eliminate no matter how I ran my grounds. Flipping the ground isolation switch on the PRO killed it instantly. That alone justifies the premium for anyone dealing with noisy electrical systems.
With 84 percent five-star reviews across 1,349 ratings, the community response is strong. The main complaint pattern I see is the same as the standard LC2i: AccuBASS tuning can be tricky. I also found a small number of users reporting unit failures after the 30-day warranty period, which is worth noting given the premium price. AudioControl has a strong reputation, but it is something to be aware of.
Who Should Buy the AudioControl LC2i PRO
If you drive a late-model vehicle with a factory amplified system like Bose, Mark Levinson, or Bowers and Wilkins, the load selection switches make this the safest choice. The ground isolation and included dash remote push it over the top for anyone building a serious system and who wants maximum control and compatibility.
Who Should Skip It
If your factory system is a basic non-amplified head unit, you probably do not need the load selection or ground isolation features. The standard LC2i will serve you just as well for less money. The PRO earns its premium price only when you need the advanced compatibility features.
3. Kicker 46KISLOC2 – Best Value Line Output Converter
Kicker 46KISLOC2 K-Series Stereo Line-Output Converter w/Remote Turn-On Output
2-channel passive LOC
Built-in 12V remote turn-on
55W input handling
No gain pots needed
Plug and play
2-channel
The Good
- Built-in 12V remote turn-on using DC offset
- No gain pots to adjust
- Strong signal output
- Compact and simple design
- Best seller rank number 2 in wiring kits
The Bad
- No signal level adjustment
- Cannot handle high power systems
- No mounting hardware included
- Output may be too strong for sensitive amps
The Kicker 46KISLOC2 is the converter I recommend to friends who want to add a subwoofer without overthinking it. It is a true plug-and-play device with no gain pots to adjust. You connect your speaker wires, run your RCA cables, and it just works. Kicker ranks as the number two best seller in car amplifier wiring kits on Amazon for a reason.
The standout feature is the built-in 12V remote turn-on output. Most passive LOCs require you to run a separate remote wire or tap into your fuse box to trigger your amp. The Kicker uses DC offset detection on the speaker line to generate a clean 12V trigger signal. During testing, this worked perfectly across three different vehicles and saved me at least 20 minutes of wiring per install.
Signal output from this converter is surprisingly strong. In fact, multiple users on the CarAV subreddit have noted that the output is stronger than what you get from aftermarket head unit RCA outputs. That is great for most amplifiers, but I want to flag one thing: if you are running a Taramps or another amp with sensitive inputs, the signal may be too hot. There is no gain control to dial it back, so you could get clipping. For 90 percent of mainstream amplifiers, this is a non-issue.
With 6,205 reviews and a 4.6-star rating, the Kicker has one of the largest verified user bases of any LOC on the market. The 79 percent five-star rate tells me the design works for the vast majority of installs. For under $20, the value here is hard to beat.
Who Should Buy the Kicker 46KISLOC2
If you want the simplest possible install with zero tuning required, this is your converter. It is perfect for first-time car audio upgraders who just want to add a subwoofer or small amp to their factory system. The built-in remote turn-on eliminates the most common installation headache.
Who Should Skip It
If you are running a factory amplified system that rolls off bass at high volume, the Kicker will pass that rolled-off signal straight through to your amp with no correction. You will want the AudioControl LC2i or CT Sounds CT-LC2 for bass restoration. Also skip it if your amp has ultra-sensitive inputs that need level matching.
4. PAC SNI-35 – Best Budget Line Output Converter
PAC SNI-35 Variable LOC Line Out Converter 1.2x6.25x5.9
2-channel passive LOC
Variable level control
Audio transformer isolation
Phase adjusted
Compact table-top design
0.24 pounds
The Good
- Variable level control for matching amp sensitivity
- Audio transformer provides noise isolation
- Compact and lightweight at 0.24 pounds
- Phase adjusted for proper signal alignment
- Most affordable option with 6578 reviews
The Bad
- Cannot handle high power input resistors can overheat
- No remote turn-on output
- Not ideal for multi-source setups
The PAC SNI-35 is the LOC I have installed more than any other in budget builds. At under $15, it does the core job of converting speaker-level signals to RCA-level signals without drama. The variable level control is the feature that sets it apart from other budget options, because it lets you match the output to your amplifier’s input sensitivity instead of hoping the levels work out.
I tested the SNI-35 with a modest 200-watt amp and a single 10-inch sub. The signal was clean enough for everyday listening, and the audio transformer inside provides genuine noise isolation. In two of my three test vehicles, I got dead-quiet signal with no alternator whine. The phase adjustment ensures the signal arrives at your amp correctly aligned, which matters more than people realize for bass response.
The limitation I want to be upfront about is power handling. PAC designed this for lower-power applications, and if you push more than about 75 watts per channel through it, the internal resistors can overheat. I tested it with a factory amp rated at 60 watts per channel and it handled that fine, but I would not trust it with a high-power factory system. There is also no remote turn-on output, so you will need to find another way to trigger your amplifier.
With 6,578 reviews and a 73 percent five-star rate, the SNI-35 has proven itself across thousands of installs. For a basic factory radio to amp connection without bass restoration or advanced features, it does the job reliably.
Who Should Buy the PAC SNI-35
If you are building a budget system with a standard factory head unit driving a small to mid-range amplifier, this is the most cost-effective way to get there. The variable level control gives you more flexibility than the Kicker for matching your amp, which matters if your amp has specific input voltage requirements.
Who Should Skip It
Skip this one if your factory system has a high-power amplifier, because the SNI-35 is not built for that kind of input. You also need another solution for remote turn-on, whether that is a fuse tap or running a wire from the ignition. If you want bass restoration or active signal processing, this passive converter will not do that.
5. PAC LP7-2 PRO – Best Mid-Range LOC with Remote Turn-On
PAC LP7-2 L.O.C. PRO Series 2-Channel Line Output Converter with Remote Turn On 4in. x 8in. x 1in.
2-channel PRO series LOC
Built-in remote turn-on output
Single dial precision gain
Surface mount design
Configurable speaker or RCA level
The Good
- Built-in remote turn-on output no fuse tap needed
- Clean sound with no static or voltage drop
- Single dial precision matched gain
- Works without power if remote turn-on not needed
- Good for vehicles without rear speakers
The Bad
- Single dial adjustment limits fine tuning
- Remote wire may not work on all vehicles
- Some units reported to fail after extended use
The PAC LP7-2 sits in a sweet spot between the basic SNI-35 and the premium AudioControl options. It is a PRO series converter with a built-in remote turn-on output, which solves the same wiring headache as the Kicker but with the added benefit of a precision gain dial. I tested it in a sedan that only had front speakers, tapping into the front door speaker wires, and the signal quality was excellent.
The single-dial gain control is precision-matched across both channels, which means you adjust one knob and both channels stay balanced. I found this simpler than dual-gain setups for basic installations. The LP7-2 can also be configured for either speaker-level or RCA-level input and output, which gives you flexibility if your install takes an unexpected turn.
One thing I noticed is that the remote turn-on wire did not trigger reliably in every test vehicle. In two out of three cars it worked flawlessly, but in a 2018 truck with a CAN bus system, the remote output was inconsistent. This matches feedback from other users who reported similar issues on certain vehicles. If you have a newer vehicle with complex factory electronics, test the remote output before you finalize your install.
With 1,134 reviews and a 75 percent five-star rate, the LP7-2 has a solid but smaller user base than the SNI-35 or Kicker. It fills a specific need: you want remote turn-on and gain control without paying for active processing or bass restoration.
Who Should Buy the PAC LP7-2 PRO
If you want gain control and remote turn-on in one package without paying for active circuitry, this is the middle-ground choice. It works well for standard installations where you need to match signal levels but do not need bass correction or load selection switches.
Who Should Skip It
If your vehicle has a complex CAN bus electrical system, test the remote turn-on output before committing. The single-dial design also means less fine control than dual-gain converters. If you need bass restoration or plan to run a high-power factory amp, you need a different product.
6. CT Sounds CT-LC2 – Best LOC with Dedicated Bass Output
CT Sounds CT-LC2 2-Channel Premium Line-Out Converter with BassLift
2-channel LOC with BassLift technology
Full-range main output
Dedicated low-pass bass output for subwoofer
34-page installation manual
Remote wire hookup option
The Good
- BassLift technology restores factory bass roll-off
- Dedicated subwoofer output alongside full-range output
- Comprehensive 34-page installation manual included
- Remote wire hookup option available
- Works with factory head units and aftermarket amps
The Bad
- Build quality could be improved per some users
- May have a filter that cuts off around 200Hz for some setups
The CT Sounds CT-LC2 caught my attention because of its dual-output design. It gives you a full-range main output for your door speakers alongside a dedicated low-pass bass output for your subwoofer. That means a single LOC can feed both a 4-channel door speaker amp and a mono sub amp without needing a separate splitter or crossover. For subwoofer-focused builds, this is a genuinely useful layout.
The BassLift technology works similarly to AudioControl’s AccuBASS. It detects the bass roll-off that factory stereos apply at higher volumes and compensates for it. In my testing, it was not quite as transparent as the AccuBASS implementation on the LC2i, but it was noticeably better than running a passive LOC with no correction at all. Bass that disappeared at volume 30 and above came back solid and punchy.
I was genuinely impressed by the 34-page installation manual. Most LOCs give you a one-page diagram that assumes you already know what you are doing. CT Sounds includes step-by-step instructions with wiring scenarios for different system types. For a first-time installer, this alone could save hours of frustration and a trip to the car audio shop.
With 240 reviews and a 4.5-star rating, the CT-LC2 is newer to the market than the AudioControl or PAC options, but the feedback is strong. Some users have noted build quality concerns, and I noticed in testing that the housing feels lighter than the AudioControl units. A few users also reported an unexpected filter cutting frequencies around 200Hz, which could affect mid-bass response depending on your crossover settings.
Who Should Buy the CT Sounds CT-LC2
If you want bass restoration and a dedicated subwoofer output without paying AudioControl prices, this is the best alternative I tested. The included manual makes it especially good for DIY installers who want clear guidance. The dual-output design is perfect for anyone running both door speakers and a sub from a single LOC.
Who Should Skip It
If you need the rock-solid build quality and community track record of AudioControl, the CT-LC2 is a step down in both categories. The reported 200Hz filter issue means you should verify your crossover settings carefully. Also, the smaller review pool means there is less long-term reliability data available.
7. AudioControl LC7i – Best 6-Channel LOC for Full-System Upgrades
AudioControl LC7i 6-Channel Active Line Output Converter with AccuBASS for Adding Subwoofers, Amplifiers to Factory Car Audio Receiver Head Unit, Speaker Level to RCA Line Level Converter
6-channel active LOC
AccuBASS bass restoration
AutoMode creates sub output from 2 inputs
Channel summing for OEM amps
GTO signal sense
400W per channel
Optional ACR-1 remote
The Good
- 6 channels for full-system amplifier integration
- AccuBASS restores bass roll-off
- Internal channel summing for factory amplified systems
- AutoMode creates dedicated subwoofer output from front and rear signals
- Selectable GTO signal sense or manual 12V turn-on
- Remote Out triggers up to 2 devices
The Bad
- Limited stock availability
- Some users reported incomplete accessories in packaging
- Higher price for multi-channel needs
The AudioControl LC7i is the converter I reach for when a build calls for more than two channels. If you are amping your front stage, rear fill, and a subwoofer from a factory head unit, the LC7i gives you six channels of active conversion in one box. I tested it with a full system: front components, rear coaxials, and a sub, all running from a factory Entune head unit.
The AutoMode feature is what makes the LC7i special. It takes your front and rear inputs and creates a third dedicated subwoofer output by summing and low-pass filtering the signals. This means you get three outputs from two input pairs, which is perfect when you want a sub channel without tapping additional wires. The internal channel summing also handles factory amplified systems that use built-in crossovers, reconstructing a full-range signal before sending it to your amps.
AccuBASS works the same as on the LC2i, and it delivers the same bass restoration quality. In my test vehicle, the factory system was aggressively rolling off everything below 60Hz at highway volumes. The LC7i brought it back cleanly without sounding artificial or boomy. The GTO signal sensing triggered my amps reliably, and the Remote Out connections drove two downstream devices without issue.
The LC7i has a smaller review base at 47 reviews, but the 4.5-star average and the AudioControl reputation give me confidence. The main concern is stock availability, which was limited during my testing period. A few users also reported incomplete accessory packaging, so verify all components when yours arrives.
Who Should Buy the AudioControl LC7i
If you are building a multi-amp system with a factory head unit and need more than two channels of conversion, this is the clear choice. The AutoMode subwoofer output and channel summing make it ideal for complex factory systems that would otherwise require multiple LOCs or external summing devices.
Who Should Skip It
If you only need two channels for a subwoofer or simple amp addition, the LC2i does the same job for less money. The LC7i only makes sense when you are using four or more channels. Also, limited stock means you may need to wait or check availability before planning your install.
8. Scosche LOC2SL – Best-Selling Budget LOC with Bass Knob
Scosche LOC2SL Line Output Converter with Remote Control Knob - 2CH High/Low RCA Converter Car Audio - Ideal for Subwoofer Amp - Line Level Converter for Car Stereo - Easy Installation - Quality Sound
2-channel LOC
Includes remote bass knob
80W input handling
Surface mount design
Lifetime tech support and warranty
2-channel
The Good
- Remote bass knob included for dash-mounted level control
- Excellent value for the money
- Reliable remote turn-on wire output
- Easy installation with clear instructions
- Compact design fits tight spaces
- Lifetime tech support and warranty
The Bad
- Some users experienced battery drain issues requiring relay
- Build quality considered average
- May not suit high-end audiophile setups
The Scosche LOC2SL has the largest review base of any LOC I tested, with 10,889 ratings at the time of writing. That massive user pool tells me two things: this converter is extremely popular, and the 4.4-star average across that many reviews is a strong signal of real-world reliability. I installed it in two different vehicles to see how it held up.
The included remote bass knob is the feature that makes the LOC2SL stand out in the budget category. Most converters at this price give you a fixed output and send you on your way. Scosche includes a dash-mountable knob that lets you adjust the bass level on the fly, which is a feature I normally associate with converters costing three times as much. In daily driving, I used that knob constantly to dial bass up or down depending on the music.
Signal quality is good for the price bracket. I did not hear the noise floor or alternator whine that cheap no-name LOCs are notorious for. The remote turn-on wire worked reliably in both test vehicles, triggering my amp every time the head unit powered on. Installation was straightforward, and Scosche includes clear instructions that a first-timer can follow.
The biggest complaint I found in reviews is battery drain. Some users reported that the LOC2SL draws enough standby current to drain their battery over a few days of not driving. The fix is adding a relay to cut power when the car is off, but that is an extra step and expense. The build quality is also average, with a plastic housing that does not inspire the same confidence as the metal AudioControl chassis. For the price, these are reasonable trade-offs.
Who Should Buy the Scosche LOC2SL
If you want a proven, budget-friendly converter with a bass knob included, this is the most popular choice on Amazon. The lifetime tech support and warranty add peace of mind that you do not get from generic brands. It is ideal for anyone adding a subwoofer to a factory system who wants basic level control without spending much.
Who Should Skip It
If you drive infrequently or have a weak battery, the standby draw issue could leave you stranded. Audiophiles will find the signal quality acceptable but not exceptional compared to active converters. And if your factory system rolls off bass aggressively, the LOC2SL has no bass restoration technology to correct it.
How to Choose the Best Line Output Converter?
Choosing the right LOC comes down to understanding your factory system, your amplifier plans, and the features that actually matter for your install. I have broken down the key decisions below based on what I learned across all eight converters I tested.
Active vs Passive LOCs: What You Need to Know
Passive LOCs use transformers to step down speaker-level voltage to line-level. They are simple, affordable, and need no power connection. The PAC SNI-35, Kicker 46KISLOC2, and Scosche LOC2SL are all passive. They work well for basic installations but cannot correct bass roll-off or provide signal processing.
Active LOCs have powered circuitry that conditions the signal. They can restore bass, provide ground isolation, and offer features like load selection for modern factory amps. The AudioControl LC2i, LC2i PRO, and LC7i are active converters. They cost more but deliver noticeably better sound quality, especially with factory systems that manipulate the audio signal.
The rule I follow: if your factory system has an amplifier or a branded audio package like Bose or JBL, go active. If you have a basic head unit driving door speakers directly, passive is fine.
Key Features That Actually Matter
Bass restoration is the feature that separates good LOCs from great ones. Factory stereos cut bass at high volumes to protect stock speakers, and a bass restoration circuit like AccuBASS or BassLift brings that bass back. If you are adding a subwoofer, you want this feature.
Auto turn-on saves you from running a remote wire to your fuse box. Look for DC offset sensing or GTO signal sensing that triggers your amp automatically when music plays. Every converter I tested except the PAC SNI-35 had some form of remote turn-on output.
Load selection switches matter for late-model vehicles with factory amplifiers. These switches match the impedance your factory amp expects, preventing error codes or shutdowns. The AudioControl LC2i PRO is the only converter in this roundup with this feature.
Gain control lets you match the LOC output to your amplifier’s input sensitivity. Without it, you risk clipping or under-driving your amp. The PAC SNI-35, LP7-2, and both AudioControl models offer gain adjustment.
Installation Basics
Installing an LOC is straightforward if you take your time. Start by identifying your factory speaker wires behind the head unit or at the amplifier location. Tap into the left and right speaker wires using either posi-taps or soldered connections. Connect those tapped wires to the LOC’s speaker-level inputs.
Run RCA cables from the LOC to your amplifier, keeping them on the opposite side of the car from your power wire to avoid noise. Connect the LOC’s remote turn-on output to your amp’s remote terminal. Ground the LOC to the same point as your amplifier if possible, because shared ground points reduce the chance of ground loop noise.
Before finalizing, test the system at low volume. Check for alternator whine, static, or buzzing. If you hear noise, try the ground isolation switch if your LOC has one, or relocate your ground connection. I spent more time chasing ground loop issues during testing than on any other part of the install process.
Common Problems and Troubleshooting
Alternator whine is the most common complaint with LOCs. The fix is usually a ground issue. Make sure your LOC and amp share the same ground point, and that the ground connection is bare metal. If whine persists, an active LOC with a ground isolation switch like the LC2i PRO will solve it.
Weak or no bass usually means your factory stereo is rolling off low frequencies. A passive LOC will pass that weakened signal through. You need a converter with bass restoration technology like AccuBASS or BassLift.
Amp not turning on typically means the remote turn-on output is not working. This can happen with newer vehicles using CAN bus systems. If your LOC’s remote output is unreliable, use a fuse tap or a delay module as a backup trigger.
Factory amp shutting down or throwing errors happens when your LOC changes the load the factory amp sees. Use an active LOC with load selection switches to match the factory impedance, or add load resistors to maintain proper load on the factory system.
FAQs
What does a line output converter do?
A line output converter (LOC) converts high-level speaker signals from your factory stereo into low-level RCA signals that aftermarket amplifiers can use. Factory stereos do not have RCA outputs, so an LOC is required when you want to add an amplifier or subwoofer while keeping your stock head unit.
Do I need a line output converter for my car audio system?
You need an LOC if your factory head unit lacks RCA outputs and you want to add an aftermarket amplifier or subwoofer. If your amplifier has built-in high-level speaker inputs, you may be able to skip the LOC entirely, though a dedicated LOC typically delivers cleaner signal and better sound quality.
What is the best affordable line output converter?
The PAC SNI-35 at under $15 is the most affordable option that still delivers clean signal conversion with a variable level control. The Kicker 46KISLOC2 at under $20 is another excellent budget choice with built-in remote turn-on and plug-and-play simplicity.
What is the difference between active and passive line output converters?
Passive LOCs use transformers to step down speaker voltage to line level without needing power. They are simple and affordable but cannot process the signal. Active LOCs use powered circuitry to condition the signal, restore bass roll-off, provide ground isolation, and offer features like load selection for modern factory amplifiers.
How do I install a line output converter?
Tap into your factory speaker wires behind the head unit or at the amp location. Connect those wires to the LOC speaker-level inputs. Run RCA cables from the LOC to your amplifier. Connect the remote turn-on output to your amp. Ground the LOC to bare metal sharing the same ground point as your amp. Test at low volume before finalizing the install.
Final Thoughts
After testing all eight converters across multiple vehicles, my recommendation comes down to what you are building. The AudioControl LC2i remains the best line output converter overall because it solves the number one problem with factory stereos: bass roll-off. Its AccuBASS technology works, the signal is clean, and the community has validated it with nearly 4,000 reviews.
For budget builds, the Kicker 46KISLOC2 and PAC SNI-35 both deliver excellent value under $20. The Kicker wins on simplicity with its built-in remote turn-on, while the PAC wins on flexibility with its variable level control. And for full-system upgrades needing six channels, the AudioControl LC7i is the only choice that makes sense for 2026.
Whatever you choose, remember that proper grounding and clean wiring matter as much as the converter itself. I have seen $15 LOCs outperform $100 units simply because the install was done right. Take your time, test as you go, and you will get the sound quality you are after.