About the Infinity Kappa Four

Delivers power in style
Delivers power in style
This handsome little black box delivers big power and fits almost anywhere in your car. Infinity's Kappa Four 4-channel amplifier can supply four high-performance speakers with 100 watts RMS each — good news for everyone who likes it loud. You could also use this amp to power a pair of front speakers with 100 watts each, and a subwoofer with 240 watts RMS. Variable high- and low-pass filters optimize the amp's output for your speakers and subs, increasing the efficiency of the system.
Good connections
You can use this amp's preamp outputs to connect to a subwoofer amp, like the matching Infinity Kappa One 6 or Kappa One K, so your system will have plenty of low-end punch — a remote output connection on this amp will even turn on your sub amp. The Kappa Four 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. They also include an electrical anti-rotational locking (E.A.R.L.) ground terminal, which provides a more conductive and secure ground connection for the amplifier.
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 at 4 ohms in bridged mode (4-ohm stable in bridged mode)
- Class D amp technology
- separate variable high- and low-pass filters (32-320 Hz, 12 dB/octave) on front and rear channels
- preamp inputs and outputs
Other Features:
- speaker-level inputs (speaker wire-to-RCA adapters included)
- 1/0-gauge power/ground wire adapter and E.A.R.L. ground terminal included
- wiring and hardware not included with amplifier
- 4-gauge power and ground leads recommended
- fuse rating: 30A x 2
- dimensions: 10-1/4"W x 1-3/4"H x 6-15/16"D
- warranty: 1 year
- Our 60-day money-back guarantee
- MFR # KAPPAFOUR
What's in the box:
Infinity Kappa Four owner's manual
- 4-Channel amplifier
- Four 30A ATO fuses (2 installed)
- 4 Bare wire-to-RCA adapters
- EARL ground terminal (for 4-gauge wire)
- 3 Flat-head screws (Length 1/2")
- Heat shrink tube (Length 1-3/16")
- 4 Mounting screws (Length 2-3/16")
- 2-pin Remote input (Phoenix) plug
- Owner's Manual
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More details on the Infinity Kappa Four

Features & specs
Performance | ||
---|---|---|
RMS Power Output (Watts x Channels) |
100 x 4 | |
Peak Power Output (Watts x Channels) | --- | |
Power at 2 Ohms (Watts x Channels) | 120 x 4 | |
Bridged Power (Watts x Channels) | 240 x 2 | |
Minimum Impedance Bridged | 4 | |
Minimum Impedance Unbridged | 2 | |
Minimum Impedance | 2 | |
Best Frequency Response | 15-35k Hz | |
THD at Rated RMS Power | --- | |
Signal to Noise Ratio | 80 dB | |
Input Voltage | 14.4v | |
Features | ||
Amplifier Class | D | |
Low-Pass Crossover Frequency | 32-320 Hz | |
Low-Pass Slope (dB/octave) | 12 dB/octave | |
High-Pass Crossover Frequency | 32-320 Hz | |
High-Pass Slope (dB/octave) | 12 dB/octave | |
Bass Boost | No | |
Bass Boost Frequency | N/A | |
Fan Cooled | No | |
Fuse Rating | 60 | |
Speaker Level Inputs | --- | |
Preamp Outputs | 1 pair | |
Width (inches) | 10-1/4 | |
Height (inches) | 1-3/4 | |
Depth (inches) | 6-15/16 | |
Parts Warranty | 1 Year | |
Labor Warranty | 1 Year |
Product Research
Features
Power Output: The Infinity Kappa Four 4-channel amplifier delivers 100 watts RMS x 4 at 4 ohms, 120 watts RMS x 4 at 2 ohms, and 240 watts RMS x 2 at 4 ohms bridged. The amp's total peak power is 1500 watts.
Protection Circuitry: The amplifier features protection circuitry for thermal overload, DC voltage on the audio output, over- or under-voltage (<9V or >16V), and short circuits. The LED on the back panel of the amp glows red if the amp goes into protection mode.
Controls
Gain: The Kappa Four's rotary gain control let you match the amp's input sensitivity to the output of the source unit. The maximum input sensitivity of the amplifier 0.2V for a line-level input, and 2V for speaker-level input. The maximum signal level is 20V for both line and speaker level inputs. There are separate gain controls for the front and rear channels. A small screwdriver (not included) is required to set the gain.
Input Level: The Input Level switch should be set to match the type of input signal connected to the amplifier. If using line-level connections, select LO. If using speaker-level inputs, select Hi1 or Hi2. Hi2 contains a special circuit designed to fool a factory audio system to detect a speaker connected to its output, and should be used only if Hi1 doesn't work.
Crossover: The amp features switchable crossovers for the front and rear channels. On each crossover, you can choose LPF (low-pass filter), HPF (high-pass filter), or Full (no crossover). The cutoff frequency is variable, and can be set between 32Hz and 320Hz using the rotary controls. The crossovers have a 12dB per octave slope. A small screwdriver is required to adjust the frequency.
Auto Turn-on: If your stereo does not have a "Remote Out" wire, you can set the amplifier to automatically turn on when it detects a speaker level signal on the input. If you are connecting a remote turn-on lead, the switch should be left in the "off" position.
Connections
Terminals: The Infinity Kappa Four uses set screw terminals for the +12V power, ground, and speaker outputs. The terminals are located under a magnetic cover, which can easily be pried off to access the screw heads. The screws can be tightened/loosened with a Phillips-head screwdriver (not provided).
Power/Ground: The +12V Power and Ground terminals will accept up to 4-gauge wire. It is recommended that you use a minimum of 4 AWG power wire to the battery, with an in-line 100A fuse 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.
E.A.R.L. Terminal: An Electrical Anti-Rotational Locking (E.A.R.L.) terminal is provided for the ground wire. The terminal is designed for 4 AWG ground wire, and requires a large crimping tool to secure the wire. The terminal includes 3 screws to attach the terminal to your vehicle's metal chassis.
Remote Turn-On: The Remote Turn-on terminal is a 2-pin Phoenix (or Euroblock) connector that accepts up to 18 AWG wire. There are slots for "In" and "Out" cables. Not only can you connect the turn-on lead from the source unit through the "In" slot, you can connect another turn-on lead to the "Out" slot to run to a second amplifier.
Speaker Outputs: The amp features set screw terminals for connecting four speakers. The amplifier's minimum speaker impedance is 2 ohms.
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.
Speaker-Level Input: The amp includes four speaker-level adapters (bare wire-to-RCA) for connecting the amp to a factory radio or aftermarket head unit. You should insert the front and rear speaker wires from the head unit into the adapters and plug the adapters into amp's RCA inputs.
Preamp Outputs: A pair of RCA outputs is provided for sending a line-level signal to a second amplifier.
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