Kenwood KAC-649S

30W x 4 Car Amplifier

  • Kenwood KAC-649S


  • Kenwood KAC-649S

  • Kenwood KAC-649S


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Item #: 113KAC649S
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Our take on the Kenwood KAC-649S


My system has plenty of power. Who needs an amp?

You might think you don't need an amp because you have a 400-watt system in your car, or because your new stereo puts out 50 watts a channel. But those are peak wattage ratings, which may boil down to 15 or 20 watts per channel, using the more realistic RMS rating. An amp sends your speakers the power they need to deliver your music with clarity and impact, whether you're using factory speakers or high-performance components. And low-frequency reproduction requires lots of power, so an amp is an absolute must if you're adding a sub to your system.

Get your motor runnin', get out on the highway. And get a Kenwood KAC-649S 4-channel amp driving all your speakers for outstanding musical reproduction even at high volume levels. High- and low-pass crossovers are built into the front and rear channels for your convenience, while speaker-level inputs let you add this amp to any system.

  • 2-, 3-, or 4-channel output
  • Tri-way capable (Tri-Way crossover required)
  • 80 watts x 2 in bridged mode
  • 40 watts x 4 at 2 ohms
  • requires 10-gauge power and ground leads — wiring and hardware not included with amplifier
  • 80 Hz selectable low-pass crossover, 12 dB/octave
  • 150 Hz selectable high-pass crossover, 12 dB/ octave
  • speaker-level inputs
  • preamp outputs
  • 4-way protection circuitry
  • signal-to-noise ratio 100 dB
  • 11-1/4"W x 2-1/4"H x 11-5/8"D
  • 1-year warranty
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Hands-on research from the Crutchfield Labs (what are the Labs?)

Features and Specs
RMS Power Output (Watts x Channels)
30 x 4
Peak Power Output (Watts x Channels)
60 x 4
Power at 2 Ohms (Watts x Channels)
40 x 4
Bridged Power (Watts x Channels)
80 x 2
Minimum Impedance Bridged
Minimum Impedance Unbridged
Best Frequency Response
5-50k Hz
THD at Rated RMS Power
Signal to Noise Ratio
100 dB
Input Voltage
Amplifier Class
Low-Pass Crossover Frequency
80 Hz
Low-Pass Slope (dB/octave)
12 dB
High-Pass Crossover Frequency
150 Hz
High-Pass Slope (dB/octave)
12 dB
Bass Boost
Bass Boost Frequency
Fan Cooled
Fuse Rating
25 x 1
Speaker Level Inputs
Preamp Outputs
1 pair
Width (inches)
Height (inches)
Depth (inches)
Parts Warranty
Labor Warranty
Product Research
What's in the box?

Download owner's manual

  • Dark gray amplifier with silver trim
  • 25-amp blade fuse (installed)
  • 1 Speaker level input harness
  • 1 Rubber terminal cover
  • 4 Self-tapping mounting screws
  • Warranty card
  • Instructionl manual (English)
  • Instruction manual (Spanish/French)

Our Product Research Team

At Crutchfield, you'll get detailed, accurate information that's hard to find elsewhere. That's because we have our own in-house Product Research team — they open the box, verify contents, check the owner's manual, and record dimensions, features and specs. We stay on top of new products and technologies to help people make informed choices.

Inputs and Outputs
Additional Specifications


Protection circuitry:

  • Speaker output contacts ground
  • Speaker wire short
  • Unit malfunctions and DC is sent to speaker output
  • Thermal: when internal temp is high
  • Loss of ground of head unit or amp


  • Filter control switches: one for A, one for B; each one can be set for high pass (150Hz), OFF, or low pass (80Hz)
  • Operation control switches: one for A, one for B; each one can be set for stereo or mono (L channel)
  • Input selector switch: you may select A/B position when using a source unit with dual RCA outputs or A position with amplifies any signal input to the "A" by both A and B (so an RCA "Y" adapter is not needed)
  • Input sensitivity knobs (variable from 0.2 to 5V): one for A and one for B

Inputs and Outputs

Right Side of the Amplifier

  • GND: philips head screw for RCA signal ground
  • Speaker-level input: multi-pin input for use with included speaker level input harness
  • "A" and "B" line-in jacks: two pairs of gold plated RCA inputs
  • Line out jacks: gold plated RCA outputs that provide a summed signal from the "A" and "B" sets of line inputs  

Left Side of the Amplifier

  • Fuse: 25 amp fuse
  • BATT (power): gold plated screw terminal (0.55" wide)
  • GND (ground): gold plated screw terminal (0.55" wide)
  • P.CON (remote turn-on): gold plated screw terminal (0.335" wide)
  • Speaker outputs: gold plated screw terminals (0.335" wide) for front and rear, left and right loudspeakers (bridged = Left+ and Right-) 

Additional Specifications


  • Rated power output at 2 ohms: 30 watts x 4 (1 kHz, 0.8% THD)
  • Max power output at 4 ohms: 60 watts x 4
  • Max power output at 4 ohms, bridged: 160 watts X 2
  • Input impedance: 10k ohms
  • Operating voltage: 14.4 V (11-16V allowable)
  • Current consumption (1 kHz, 10% THD): 18 amps
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Add accessories for the Kenwood KAC-649S

Patch cables take the music from your stereo to the amplifier. Most amp wiring kits don't include them. See all categories & accessories

T-Spec 2-Channel RCA Patch Cables Available in 7 different lengths (14-foot)
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Your Price: $17.99
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For a more in-depth review and enhanced detailed information on the Kenwood KAC-649S, please visit the Crutchfield website product page (/ISEO-rccbcspd/p_113KAC649S/Kenwood-KAC-649S.html ).