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Rockford Fosgate RF-HLC4

4-channel line output converter

14 Reviews | 3 questions - 3 answers

Item # 575RFHLC4

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Our take on the Rockford Fosgate RF-HLC4

Small enough to fit behind your dash and never needs adjusting

When you want to add an amplifier to a car stereo that doesn't have RCA-type outputs, Rockford Fosgate's HLC4 4-channel line output converter may be the perfect solution. The HLC4 converts the high-level signal from your receiver's speaker-level outputs down to low-level signals that your amp can handle. This compact converter will fit just about anywhere.

Product Highlights:

  • 4-channel line output converter
  • input: up to 10.5-volt (about 27 watts)
  • output: up to 3 volts
  • includes ground leads to reduce noise if necessary
  • dimensions: 4-15/16"W x 1-1/16"H x 3-1/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

Works perfectly as advertised. Connected a Sound Ordnance amp to my Harley, now I am enjoying loud, clear music all of the time.

charles, Ft Worth, TX

What's in the Box:

  • 4-Channel high-level to low-level signal converter
  • 12" Speaker-level harness
  • Instructions on packaging

Rockford Fosgate RF-HLC4 Reviews

Average Customer Review(s):

(14 Reviews)

Rockford Fosgate RF-HLC4

charles from Ft Worth, TX on 2/21/2017

Crutchfield Customer Review (What's this?)

Works perfectly as advertised. Connected a Sound Ordnance amp to my Harley, now I am enjoying loud, clear music all of the time.

Pros: Easy installation, simple instructions, very durable.

Cons: None

Rockford Fosgate RF-HLC4

Matt from Texas on 11/28/2016

Crutchfield Customer Review (What's this?)

I bought the RF-HLCR to replace a PAC converter that only lasted 4mths. We'll see if this one will hold up better.

Pros: easy to install

Cons: none yet

Easy to install

Paul from Milford nh on 9/25/2016

Crutchfield Customer Review (What's this?)

Easy to install pretty straight forward makes adding equipment a breeze

Pros: Ease of use nothing to adjust pretty much plug and play

Cons: Would be nice if it was a little thinner and small

Rockford Fosgate RF-HLC4

Anonymous from Lancaster pennsylvania on 9/7/2016

Crutchfield Customer Review (What's this?)

Great simple product

Pros: Easy to use


Awesome product

Mike j from Mascoutah, IL on 7/3/2016

Crutchfield Customer Review (What's this?)

Very good product. Easy to install. When cutting the car stereo wires, make sure there is enough length on both ends of the wires. I recommend this product.

Pros: Good price, east to install.

Cons: None

Rockford loc

Rockford loc from Waynesboro, VA on 5/7/2016

Crutchfield Customer Review (What's this?)

Nice size and good quality

Pros: Nice size to be hidden and mounted out of sight.

Cons: None so far


brandon from cincinnati, OH on 3/25/2016

Crutchfield Customer Review (What's this?)

Greate easy install




Anonymous from Sabino on 1/29/2016

Crutchfield Customer Review (What's this?)

Installed on a 2008 Ram 1500 Quad Cab factory radio. Small enough to mount on backside. Works perfect.

Pros: Small

Cons: NA

Rockford Fosgate RF-HLC4

Brian from Rhode Island on 12/12/2015

Crutchfield Customer Review (What's this?)

Does job well. No issues; I gave four stars because it just does it's job. Call me back in two years and if it is still doing it's job I'll give it five.



Great product

Miket2573 from Florida on 10/4/2015

Crutchfield Customer Review (What's this?)

Great product works great

Pros: Line level works just like it was advertised

Cons: None

Rockford Fosgate RF-HLC4

Anonymous from Jackson, MO on 3/27/2015

Crutchfield Customer Review (What's this?)

It does the job...had I done a little more research I would have went with something different like a plug and go that has built in remote wire

Pros: Does work well

Cons: No remote wire

rockford rf-hlc4

jp from reno,nv on 5/25/2014

Crutchfield Customer Review (What's this?)

got this to hook up factory stereo with 5 channel amp for new speakers and sub. worked very well. ran jumper from rear speakers to sub, adjust gain, adjust fade works very well. would recommend this as a very cheap and easy way to amp your factory radio

Pros: works good, inexpensive, easy to hook up

Cons: none so far

Great product

Anonymous from oklahoma on 2/23/2014

Crutchfield Customer Review (What's this?)

This product was great. It was used to replace a cheap converter bought at walmart that produced a annlying gain tone. The ground cable and insulation took that tone away.

Pros: Great quality Ground cable Well protected

Cons: Large and in the way

Does what it needs to do.

RB from Houston Tx on 12/29/2013

Crutchfield Customer Review (What's this?)

I used this to connect a scion factory HU to a Kenwood 5 channel amp. Combining this with properly tuned gain settings on the amp, there is absolutely no distortion with the HU at max volume. I can't keep it there for long, though, for fear of hemorrhaged ears. The separate harness makes it easy to splice into the factory lines for a butterfingers like me. My only gripe is that the output levels are not adjustable. I learned the hard way that my head unit outputs the rear channels at a much lower voltage than the front - something that I was fortunately able to compensate for using the amp gain switches.

Pros: Quality, ease of installation.

Cons: Lack of adjustable outputs


Hands-on research

Product Research


4-Channel High-Level to Low-Level Converter: The Rockford Fosgate RF-HLC4 is a 4-channel high-level to low-level signal converter designed for factory or aftermarket radios that do not have dedicated low-level RCA outputs. The adapter converts high-level signal from the radio's speaker line and transforms it into a safer low-level audio signal. This allows you to add a 4-channel amplifier to your system for higher power output and better sound quality.

Speaker Level Input: The Rockford Fosgate RF-HLC4 comes with a 10-wire speaker-level harness which plugs into the converter's 10-pin connector. The speaker-level harness will need to be spliced or crimped onto your head unit's wiring harness (splicing and crimping accessories sold separately). The RF-HLC4 has an input voltage of up to 10.5V.

Pin #Wire ColorFunction
3BrownNot Used
6Purple/black RR-
8BrownNot Used
Note:Connecting the Ground leads (brown) is not necessary unless there is noise in the audio system.

Low Level Output: The Rockford Fosgate RF-HLC4 is fitted with 4 RCA jacks (Front Left/Right, Rear Left/Right). These RCA jacks connect to your aftermarket amplifier via stereo RCA cables (sold separately). The RF-HLC4 has an output voltage of up to 3V.

Mounting Options: The 4-channel high-level to low-level signal converter should be installed behind the vehicle's dash and car stereo.

Our Product Research Team

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Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

Quality and reviews.[ E  Sep 22, 2017 ]
My Installer[ Steven C/O Andrew  Aug 08, 2017 ]
It's what I needed.[ Robert  Apr 19, 2017 ]

3 questions already asked

It does not, no. It just provides the high level to low level conversion.[ Ryan  Sep 13, 2017 ]  Staff
For details on installation please contact an Advisor by phone (1-800-324-9695) or online chat. They will be able to give you the details on what you will need.[ Krissy  Feb 26, 2014 ]  Staff
No, the amp switch wire would not run through the converter. The switch wire(s) should be spliced directly to the switched 12v on the head unit. Using this for two amplifiers completely depends on your setup, and whether you want to amplify front and rear channels separately. Using a four channel amplifier combined with a separate mono amp for the sub? You can use this with two RCA "y" splitters put on either the front or rear channels. Two mono amps? Don't use this. Buy a two channel converter instead and split the signal on the RCA side.[ Ryan  Jan 14, 2014 ]

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