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Infinity Kappa K4

4-channel car amplifier with Bluetooth® connection — 100 watts RMS x 4

Item # 108K4

Infinity's Kappa K4 4-channel car amplifier can supply a couple of sets of high-performance speakers with 100 watts...

Find what Fits your vehicle

Infinity's Kappa K4 4-channel car amplifier can supply a couple of sets of high-performance speakers with 100 watts...

California customers:
Please click here for your Proposition 65 warning.

Discontinued item
15 questions - 41 answers

Item # 108K4

About the Infinity Kappa K4

High tech and stylish

Infinity's Kappa K4 4-channel car amplifier can supply a couple of sets of high-performance speakers with 100 watts RMS each — good news for all you music fans out there. Even better, you can stream music directly from a Bluetooth device to this amp, while its built-in processing restores the excitement in your music that data compression removes. Plus, the dancing, signal-level LEDs on the cover add to the amp's high-tech look and overall coolness factor.

High tech and stylish

Infinity's Kappa K4 4-channel car amplifier can supply a couple of sets of high-performance speakers with 100 watts RMS each — good news for all you music fans out there. Even better, you can stream music directly from a Bluetooth device to this amp, while its built-in processing restores the excitement in your music that data compression removes. Plus, the dancing, signal-level LEDs on the cover add to the amp's high-tech look and overall coolness factor.

Connectivity is the name of this game

You can stream music from your compatible Bluetooth device directly to the K4, for convenient, wireless play that bypasses your car's radio. The amp's preamp outputs let you connect a subwoofer amp, like the matching Infinity Kappa K1000 or Kappa K600, for better-sounding bass in your music. The Party Mode feature allows up to three different sources to stream, so more people can join in the fun. The included wired remote gives you handy controls for Bluetooth streaming, hands-free calling, Party Mode, and Clari-Fi™ signal processing.

Powerful and versatile

Need some bass power? You can switch the K4 into bridged mode and drive two subwoofers with 250 watts RMS each. A high- or low-pass filter matches the amp's output to your speakers, increasing the efficiency of the system. The Kappa K4 can accept low- or speaker-level inputs so it'll work in almost any system, and Infinity includes RCA-to-speaker wire adapters so you'll make the right connections.

Decompression saves the sound

Downloaded digital music and streaming services apply data compression to their files so you can store more of them on your devices, but compressed music sounds noticeably duller than uncompressed files. Harman's Clari-Fi™ sound restoration technology improves the sound quality of your digital music by analyzing the data and then reconstructing the parts that were removed during the compression process. You get crisper highs, increased dynamics, and clearer vocals.

Infinity Kappa K4

Kappa K4 input and control panel


Product highlights:

  • 4-channel car amplifier
  • 100 watts RMS x 4 at 4 ohms (120 watts RMS x 4 at 2 ohms)
  • 240 watts RMS x 2 in bridged mode (4-ohm stable in bridged mode)
  • separate variable high- and low-pass filters (32-320 Hz, 12 dB/octave) on front and rear channels
  • wired remote unit has controls for Bluetooth streaming, hands-free calling, Party Mode, and Clari-Fi signal processing
  • preamp inputs and outputs
  • speaker-level inputs (speaker wire-to-RCA adapters included)
  • fuse rating: 30A x 2
  • 4-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 10-1/4"W x 1-3/4"H x 6-15/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee
  • MFR # K4

What's in the box:

  • 4-Channel amplifier
  • Four 30A ATO fuses (2 installed)
  • Control panel with attached 19.5' cable
  • Control panel flush mount sleeve
  • Control panel mounting bracket
  • 2 M4 x 10mm bracket screws
  • 4 Bare wire-to-RCA adapters
  • Remote plug (Euro or Phoenix connector)
  • 4 Mounting screws (M4 x 52mm)
  • Quick Start Guide

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Product Research


Overview: The Infinity Kappa K4 is part of the Kappa series of high-performance amplifiers. This full range Class D 4-channel amplifier will accept both high-level and low-level inputs. Class D amplifiers are highly efficient and compact, generating lots of power without drawing much current or generating heat. The Kappa K4 includes Clari-Fi, an audio restoration feature that improves the sound of compressed digital files. The amp also includes a cabin-mounted control panel to give you amplifier control at your fingertips. The unit comes with spare fuses, speaker wire-to-RCA adapters, and mounting hardware.

Power Output: The Kappa K4 delivers the following power output:

  • 100 watts RMS x 4 at 4 ohms (<0.1% THD+N)
  • 120 watts RMS x 4 at 2 ohms (<0.1% THD+N)
  • 240 watts RMS x 2 at 4 ohms bridged (<0.3% THD+N)

Clari-Fi: Clari-Fi is a proprietary technology that analyzes compressed digital music files and improves them in real time. Using a predictive algorithm that restores audio content that is lost during the compression process. Clari-Fi provides extra bandwidth, especially in the high frequencies, widens the sound stage, and gives vocals a natural warmth not found in compressed files.

Control Panel: The amplifier comes with a wired control panel that provides numerous features not typically found with amplifiers. It has Bluetooth technology, and an omni-directional microphone for accepting and ending phone calls from your cell phone. Party Mode lets you pair multiple Bluetooth devices for streaming music from anyone's phone. The control panel also lets you activate the Clari-Fi feature. The panel is 4-7/16"W x 15/16"H, and has a 19.5-foot cable. It can be flush- or surface-mounted with the supplied brackets.

ADAS: The Kappa K4 has an interface for the Advanced Driver Assistance System (ADAS) that can override the audio source input to deliver a message or other audio from a connected ADAS accessory. On the amplifier, you can designate which speaker the ADAS signal is output: Front left, front right, rear left, or rear right.

Protection Circuitry: The amplifier features protection circuitry for thermal overload, over- or under-voltage (<9V or >16V), and short circuits. The LED on the top of the amp glows red if the amp goes into protection mode.

Controls: The Kappa K4's controls are located on one side of the amplifier. The rotary controls require a small screwdriver (not included) to make adjustments. The amp controls include:

  • Gain: The rotary gain controls let you match the amp's input sensitivity to the output of the source unit. The input sensitivity range of the amplifier is 0.2V and up for a low-level input, and up to 20V for speaker-level input. There are separate gain controls for the front and rear channels.
  • Input Level: The Input Level switch lets you select the type of input you are using. For high-level input, there are two settings: Hi1 and Hi2. If the audio system fails to play with an amplifier connected to its output, or you get a "speaker disconnected" message on your factory stereo, set the switch to the Hi2 position. The Hi2 position includes a circuit design to fool this type of factory system into "seeing" a speaker connected to its output.
  • Crossover: The amp features switchable crossovers that can be set to low pass (LPF), high pass (HPF), or Full Range. You can adjust the cutoff frequency of the crossover from 32Hz to 320Hz using the rotary control. There are separate crossovers for the front and rear channels.

Connections: The Infinity Kappa K4 uses set screw terminals for the +12V power, ground, and speaker outputs. The screws can be tightened/loosened with a Phillips-head or flat-head screwdriver (not provided). The amp connections include:

  • Power/Ground: The +12V Power and Ground terminals will accept up to 4-gauge wire. It is recommended that you use 4 AWG power wire to the battery, with an in-line 60A fuse (or higher) installed no more than 18" from the battery terminal. A 4 AWG ground wire (minimum) is also recommended, and attached to a metal area close to the amplifier.
  • Remote Turn-On: The Remote turn on wire connects to the supplied plastic 2-pin Euro or Phoenix connector. The connector has tiny set screws to tighten the wire, and requires a precision screwdriver (2.4mm or 3/32"). The connector has "IN" and "OUT" terminals, allowing you to daisy chain the turn-on signal to another amplifier, if needed.
  • Speaker Outputs: The amp features screw terminals for connecting four speakers. There are markings on the terminals for bridging the amplifier.
  • Speaker-Level Input: The amp includes four bare wire-to-RCA adapters for connecting the amp to a factory radio or aftermarket head unit without preamp outputs. You should attach each speaker wire from the head unit to an adapter and plug the adapter's RCA plug into the amp.
  • Line-Level Inputs: The amplifier is equipped with two pairs of RCA inputs for connecting stereo RCA patch cables from the head unit to the amp.
  • Pre-Out: A third pair of RCA jacks is provided to output the audio signal to a second amplifier, if desired.

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Customer Q&A

15 questions already asked

can this be used without the remote, i.e. just as a good quality normal amp? I don't need any of that stuff because my head unit already has it. I just need a good quality 4 channel x 100W low THD amp
[ Yoam69  Dec 15, 2019 ]
6 answers
Yes. I have never used the remote on mine.
[ ROBERT  Jan 09, 2020 ]
The remote isn't needed, however I recomend using it to bench test the amp and to disable the built in "compression compensation" (or whatever it was called) on first use. That was enabled and indicated on the led display. After disabling, the setting stayed disabled. Amusingly enough, with the native Bluetooth, the remote could run a simple car audio system without a head unit at all.
[ Philip  Jan 07, 2020 ]
[ WILLIAM B  Jan 06, 2020 ]
Yes it works fine without the remote. I use it without the remote in my Chevelle. Really great amp too!
[ lucas  Jan 06, 2020 ]
I only use as a head unit, so yes. Excellent for what you're looking for.
[ Martin  Jan 06, 2020 ]
I have it hooked up as a regular amp, and never even hooked up the remote to it. Love the clarity of this amp. I have it pair with kappa infinity two ways up front and kicker 6 3/4 mid range bass in the back. I recommend it highly.
[ John  Jan 06, 2020 ]
What are the dimensions of the external control panel?
[ Torin  Oct 14, 2019 ]
2 answers
Hi Torin, thank you for your question. The control panel for the Infinity Kappa K4 is 4-7/16"W x 1-5/16"H, and has a 19.5-foot cable.
[ Jess  Oct 22, 2019 ]  Staff
[ Dewayne  Oct 22, 2019 ]
what are the dimensions of the amp?
[ Nolan  Jun 16, 2018 ]
4 answers
Amp is trash... burnt out within months of owning it....
[ joel  Jun 21, 2018 ]
260 x 177 x 43mm 10-1/4" x 7" x 1-3/4" I can't link the pdf manual this came from but if you google Infinity Kappa K4 the first hit is the manufacturer's site.
[ Greg  Jun 20, 2018 ]
[ eric  Jun 20, 2018 ]
6 x 10 x 1.8 inches
[ Mark  Jun 20, 2018 ]
Do you have to hook up the hard wired remote if you just want to connect Bluetooth to stream but don't plan on taking calls or using other features?
[ Kyle  Mar 10, 2018 ]
2 answers
Sorry Ms. Susan K.; My Infinity Kappa 1000 & Kappa 4 Amps, are still in boxes in my Bimmer's Trunk, I still need to buy one more K1000, K2, and another K4 from Crutchfield of course, so I havn't Really set a wire plan, but when I installed the module in the console of my Bimmer, there is a switch solely for BT. The Infinity Module is (null) right now, but I share the same druthers, BMW BT, Dension BT and now infinity. I hope all works out. V/R. EAM - Temecula, CA
[ Eduardo  Mar 25, 2018 ]
No you dont. But to be honest its as simple as just pluging it into the amp and you can leave it rolled up next to amp or actually run it to your dash. Very simple. But you dont technically need it to use blue tooth. But this is not your best option if all your looking for is blue tooth. You would only buy this if you were going to put all 4 car speakers to the amp and the bluetooth is extra. My deck in truck is bluetooth so i dont actually bother using the amps BT. And the amps clarify technology makes a big difference in sound btw.
[ Ethan  Mar 25, 2018 ]
If using this amp with Polk db6502 speakers, should the polk supplied crossovers still be used?
[ Randy  Mar 09, 2018 ]
4 answers
Don't see why not. Odds are they were designed together will sound great together. Give them a little time. If you think they aren't what you like soundwise, then you might consider a change or upgrade.
[ Michael  Apr 02, 2018 ]
I'm not 100 percent sure but I'll note that this amp give a ton of noise/whine. It works great but the engine noise is kind of annoying
[ Linda  Mar 25, 2018 ]
[ jim  Mar 25, 2018 ]
Yes use the same crossovers for you speakers does not have anything to do with amp.
[ Ethan  Mar 25, 2018 ]
I'm looking to purchase this amp for 4 of my new alpine type s speakers. I also have a self amplified kenwood 8" under the seat sub (Ksc-11). Can I connect this to the amp just so I can have whatever I play on Bluetooth play out of the sub as well? Thank you
[ Josh  Feb 24, 2018 ]
3 answers
yes it has a preamp out
[ eric  Mar 21, 2018 ]
Yes, this amp basically acts like a head unit when you connect your music source to its Bluetooth.
[ Patrick  Mar 15, 2018 ]
Josh, This amp is more than a way to connect bluetooth audio as it also has a hands free feature. Unless you still listen to radio or CDs toss the Kenwood connect all the speakers directly and hide the Mic and enjoy. But if you still have some emotional attachment to FM/XM or Cds well yes it can be connected to it either thru high power out or low power out very versatile. It must be the device connected directly to your speakers and it has a powered sub out connection. Hope this helps I bought it to eliminate the head unit and allow for a very clean uncluttered interior. I hid the controller under the lid of my armrest.
[ Jon of Fern Park  Mar 14, 2018 ]
If I only hook up 2 channels Will it be using power for those 2 channels only or will I using 4 channels worth of power?
[ stunami  Nov 12, 2017 ]
4 answers
Each channel has its own independant maximum power output. So if it's 60 watts per channel rms then each channel will put out 60 watts. Each channel works separately.
[ Jim  Nov 23, 2017 ]
You can bridge the left and rt channels for more power for those 2 channels
[ eric  Nov 18, 2017 ]
It depends on how you hook them up. If you have them bridged at the amp, you can get full power to 2 speakers .
[ Robert  Nov 17, 2017 ]
It depends on how you wire it. If you just use 2 channels wired as you would normally wire them, you will only have 2 channels worth of output. If you bridge the 4 channels into 2 channels, you usually get more than double the RMS power. For this amp, 2 bridged channels can put out 240W RMS, but you must make sure that your speakers have high enough impedance. This amp can push 2 ohm speakers in the standard configuration, but if you bridge the channels, you need to wire in 4 ohm speakers. The wiring configuration to bridge channels should be in the amps manual, but it is always very straight forward. Usually you would bridge the 2 front channels together, and the 2 rear together, by using, for example, the positive terminal of one of the front channels, and the negative of the other front channel. Just make sure to verify this in the manual so you don't break anything.
[ Louis  Nov 17, 2017 ]
In addition to using this as a Bluetooth streaming device, I'd like to run my factory head unit through this amplifier so when i'm not listening to my iPhone, I can still listen to local radio stations. Is it possible to hook my factory head unit to this amplifier?
[ 2015 Chevy Trax  Oct 15, 2017 ]
3 answers
It is good to ask questions but doing your own research is more powerful in terms of correct information. Crutchfield and Infinity are good about allowing anyone access to the owners manuals. You can hook a main unit with line inputs (RCA plugs) or high level inputs (speaker out on main unit). This amp comes with a small controller you can mount in a convenient location to change which input gets channeled through the amplifier.
[ ken  Oct 15, 2017 ]
Yes, there are high level (speaker) inputs and if your radio is factory amped there are low level input rca adapters included as well. It is a very nice set up.
[ Rob  Oct 15, 2017 ]
Yes line level inputs can be used...the amo comes wirh special rca hook ups.... this is a terrific amp n
[ eric  Oct 15, 2017 ]
Can this amp be used as a stand alone Bluetooth player without the need of a head unit?
[ scott  Sep 24, 2017 ]
3 answers
I am running it like this now. I hooked the speakers up directly to the amp and connected my phone with no issues.
[ Jacob  Sep 25, 2017 ]
Yes, but in my opinion with head unit sounds better with use of a USB drive and you have more control over sound. Also depends on the quality of songs.
[ Jeremy  Sep 25, 2017 ]
Yes it can. I have it in my Buick LaCrosse and I can have it k it up to the amp or my stock head unit. The amp has its way wn tuning also.
[ Patrick  Sep 24, 2017 ]
How would I replace my factory amplifier in my 2017 Honda Crv Exl with this but leave the head unit?
[ Julie  Sep 02, 2017 ]
1 answer
The K4 does feature "speaker level inputs" so, you can tap the factory amplified speaker leads to provide the audio signal. Because these are "high level" inputs, the factory amplifier will need to remain in order to provide the audio signal into the new amp. For additional assistance and personalized recommendations, feel free to contact us directly by phone or through our online chat service:
[ Ryan  Sep 06, 2017 ]  Staff
guessing if i was to use it with a dsp. this amp would take the dsp out of the equation if i am streaming via Bluetooth . so my sound imaging set up would do no good correct?
[ dopesrt  Aug 23, 2017 ]
2 answers
If you use the Kappa Supplied Bluetooth, yes, DSP would be no good. If you blue tooth into DSP then RCA into Amp, would be fine.
[ Martin  Jan 06, 2020 ]
You are correct. Sending audio into this amp via Bluetooth would bypass a DSP and not use any part of the audio adjustments you set up with it. There are ways to build a system so this doesn't happen. I recommend contacting an advisor on 1-800-324-9695 for a personal recommendation. My Bio:
[ Paul  Aug 28, 2017 ]  Staff
Can Polk db652 speakers handle this amp?
[ Michael  Aug 05, 2017 ]
4 answers
I am driving infinity kappa 6.5 rated at 65w and 6x9 rated at 125w. Just turned the gain down a bit on the 6.5s (separate front and rear gain controls) + turned UP the lowpass for the 6.5s (to 100hz) so as not to drive the bass so hard. The amp has an automatic shut off when distortion is too high, I've had Zero issues with Speaker wear. Very loud, very clear.
[ Martin  Jan 06, 2020 ]
If the RMS wattage is right they should work fine. Infinity speakers run low amperage, therefore there amps are low amperage. You might need a more powerful amp if the polk speakers have a higher peak wattage
[ Kevin  Aug 05, 2017 ]
I can't answer whether the db652's can handle it, but I have the Polk DB6502 component speakers and they perform beautifully with this amp. From a glance, the db652's have a similar response range...actually they look like the same speakers with a built in tweeter instead of the separate tweeter. I would say yes this is a good pairing just from the specs.
[ Chris  Aug 05, 2017 ]
Definitely. I have the db652 and db6502 components hooked to this amp. Perfect fit.
[ Jared  Aug 05, 2017 ]
How to connected to factory stereo 2015 toyota camry xle with jbl speaker ? I want buy Infinity Kappa K4 . Thanks
[ Thinh  Jul 04, 2017 ]
1 answer
For details on installation please contact an Advisor by phone (1-800-324-9695) or online chat. They will be able to pull up your vehicle and give you the details on what you will need for an installation.
[ Kenny  Jul 06, 2017 ]  Staff
can this be used just as an entertainment center for a vehicle? I have a tablet that I would like to use as a stereo instead of a head set.
[ Matt  Apr 17, 2017 ]
1 answer
Sure! You can pair a Bluetooth streaming device (such as a tablet) to the Infinity amplifier and use that as the main audio source instead of an actual radio/head unit. If you would like to discuss in further detail, please feel free to contact an Advisor directly by phone (1-800-324-9695) or online chat. Hope that helps!
[ Larry  Apr 21, 2017 ]  Staff

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