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Alpine KTA-450 Power Pack

Compact 4-channel car amplifier — 50 watts RMS x 4

Item # 500KTA450

If adding more power makes music sound better, Alpine's KTA-450 power pack will make a significant improvement in...

Find what Fits your car

If adding more power makes music sound better, Alpine's KTA-450 power pack will make a significant improvement in...

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About the Alpine KTA-450 Power Pack

Bump up the power

If adding more power makes music sound better, Alpine's KTA-450 power pack will make a significant improvement in your system. This compact 4-channel amplifier puts out 50 watts RMS per channel from a tiny chassis that'll fit almost anywhere in your vehicle. KTA-450 uses Alpine's Dynamic Peak Power (DPP) technology to deliver a quick energy boost when needed, virtually doubling the amplifier's output power on musical peaks.

Bump up the power

If adding more power makes music sound better, Alpine's KTA-450 power pack will make a significant improvement in your system. This compact 4-channel amplifier puts out 50 watts RMS per channel from a tiny chassis that'll fit almost anywhere in your vehicle. KTA-450 uses Alpine's Dynamic Peak Power (DPP) technology to deliver a quick energy boost when needed, virtually doubling the amplifier's output power on musical peaks.

Alpine Authorized Online Dealer

PowerStack Installation

Here's a very cool idea from Alpine — the package includes a PowerStack bracket for mounting the amp in your dash behind Alpine's shallow chassis iLX-W650 digital multimedia receiver. The combined depth of receiver and amp is still less than 5", so it'll fit in a wide variety of vehicles. The receiver and amp together make a feature-filled and powerful sound system that you'll enjoy for many miles.

Installation Notes: This power pack will not work in systems with a factory amplifier. Wiring and fuse are not included — 12-gauge power and ground wires and a 20A inline fuse at the battery are required.

Alpine KTA-450

PowerStack bracket with KTA-450


Product highlights:

  • 4-channel car amplifier
    • 50 watts RMS x 4 at 4 ohms (45 watts RMS x 4 at 2 ohms)
    • 100 watts RMS x 2 bridged at 4 ohms
  • CTA-2006 compliant
  • Dynamic Peak Power (DPP) technology adds a burst of power when needed
  • selectable high-pass filters (60, 80, 120 Hz at 12 dB/octave) on front and rear channels
  • preamp and speaker-level inputs
  • selectable 2- or 4-channel input
  • PowerStack bracket included for mounting amp behind Alpine iLX-W650 digital multimedia receiver (#500ILXW650)
  • wiring, hardware, and fuse not included with amplifier
    • 12-gauge power and ground leads and a 20A fuse recommended
  • dimensions: 7"W x 1-3/8"H x 3-9/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee
  • MFR # KTA-450

What's in the box:

  • 4-Channel amplifier
  • 12" Input/Output/Power harness
  • 1 Head unit (iLX-W650) mounting bracket
  • 2 Universal mounting brackets
  • Four M5x6mm Allen head machine screws (3mm)
  • Two M2.6x8mm Machine screws
  • Four 3/8" Screws
  • Four 7" Zip Ties
  • Owner's Manual (English/ French/ Spanish)
  • Warranty information
  • On-line product registration information

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More details on the Alpine KTA-450 Power Pack

Mark G.

Product Research


Overview: The Alpine KTP-450 is a Power Pack series amplifier, meaning it's small, and can often be mounted in close proximity to the head unit.

Note: This high-powered amp won't work in systems where an outboard factory amplifier is active. If the vehicle has a factory amplifier, the factory amp must be completely bypassed (this may result in lost speaker channels, if factory amp has more than 4 channels).

Mounting: Two types of mounting brackets are included with the amp, plus four zip ties. The first mounting bracket is designed to mount the amp to the back of Alpine's iLX-W650 digital media receiver. The iLX-W650 is just over 2¾" deep by itself, so even with the added depth of the amp (totaling just over 5"), the combination fits in almost any dash with a Double DIN opening. The bracket also leaves a gap of approximately ¾" between the amp and head unit, so most of the wiring can be routed to that space. The second option is a pair of universal brackets that bolt to the ends of the amp, and provide a mounting flange with four screw holes. The chassis of the amp also has four tabs, through which the included zip ties can be looped to attach the amp behind the dash.

CTA-2006 Compliant: CTA-2006 is a system of testing and measurement for mobile audio amplifiers. This voluntary standard advocates a uniform method for measuring an amplifier's RMS power output and signal-to-noise ratio. The criteria for measuring amplifier power uses a DC input voltage of 14.4 volts and the RMS power output is measured over a frequency range of 20 Hz to 20 kHz (for full range amplifiers), with 1% or less Total Harmonic Distortion plus noise (THD+N). Signal-to-Noise ratio is measured in weighted absolute decibels (dBA) at a reference of 1 watt into 4 ohms. CTA-2006 standards allow consumers to compare car amplifiers and receivers under the same conditions (apples to apples).

CTA-2006 Specifications:

  • Power Output: 50 watts RMS x 4 into 4Ω
  • Signal to Noise Ratio: 82 dBA (measured at 1 watt into 4Ω)

Other Specifications:

  • Power Output:
    • 2Ω: 45 watts RMS x 4 (14.4 volts, ≤1.0% THD+N)
    • Bridged: 100 watts RMS x 2 (4Ω minimum)
  • Signal to Noise Ratio: 95 dB (at rated power output into 4Ω)
  • THD+N: <0.1% (at rated power into 4Ω or 2Ω)
  • Frequency Response: 15 Hz to 50 kHz (+0/-3 dB)

Controls: There are DIP switches on the amp to set input signal type, output configuration, and independent controls for the front and rear channel gain and crossovers:

  • Gain: two rotary controls; adjustable from 152mV to 2.8 volts line level and 330mV to 6.05 volts speaker level
  • High Pass Crossover: select 60Hz, 80Hz, 120Hz, or Off (full range)
  • Input Type: set to RCA (line level) or speaker level
  • Amp Configuration: 4-channel or 2-channel (bridged)

Harness: All the wiring for power, input, and output is in one harness. The wires in the harness are one foot long and it plugs into a recessed area on the amp, with openings on the side and bottom, so the wires can be routed in either direction.

Power/Ground: The power and ground wires in the harness are 14-gauge. (Actually each has two 16-gauge wires from the harness, merged to a single 14-gauge wire.) The power wire should be extended and connected directly to the battery, using an in-line 20-amp fuse near the battery terminal.

Note: Neither the amp nor the harness has a fuse, so using an in-line fuse at the battery is absolutely necessary.

Signal Inputs: There are four male RCA plugs on the included harness for line level inputs. If your source unit has no line level outputs, the RCA plugs can be cut off and a speaker level signal wired directly to the discrete positive and negative wires. (You can also use optional Speaker Wire to RCA adapters.)

Note: You will need to connect the amplifier's remote turn-on lead wire (blue/white) to your source unit's remote turn-on lead when using a line level (RCA) input. The amp has a remote sensing feature, so the remote turn-on connection is not necessary when using a speaker level input.

Speaker Output: The harness has unterminated wires for the four speaker outputs.

Dimensions: Because two types of brackets are included, the amp has multiple possible dimensions:

  • Chassis Only:
    • Width: 7.0"
    • Height: 1.33"
    • Depth: 3.56"
  • With Universal Brackets:
    • Width: 7.8" (includes mounting flange)
    • Height: 1.56"
    • Depth: 3.56"
  • With Head Unit Bracket: for mounting to the back of the Alpine iLX-W650
    • Width: 7.0"
    • Height: 3.56"
    • Depth: 2.23"

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Customer Q&A

Crutchfield asked: Why did you buy this?
Better and louder sound quality [ Asif  Jun 29, 2020 ]
recommended by a professional audio installer [ Jose Barajas  Jun 26, 2020 ]
Fits snug behind head unit saving space and giving speakers the power it needs. [ Alexandro  Jun 22, 2020 ]
Wanted more power. I have other amplifiers, but this is very easy to install from what it looks like [ Thomas  Jun 16, 2020 ]
I like the compact size and piggy back compatibility with the stereo that I purchased. This will fit perfectly inside the space where they'll be installed. [ michael  May 31, 2020 ]
needed it and they had it [ Willie  May 23, 2020 ]
50 watts per channel in the Jeep seems to be exactly what I'll need. I like that it fits right on the back of the stereo but that wasn't a deal breaker. Even aside from the brand, size, and fit to the Alpine ILX-W650- it just seems like a very good stand-alone 4 channel amp, compared to comparable units. [ Shaun  May 15, 2020 ]
so i can turn it up to 11. [ S  May 02, 2020 ]
Loved my 445, adding this one to another car... [ Robbie  Apr 21, 2020 ]
Wanted to add power to the Alpine iLX radio without taking up more space, this unit will fit perfectly behind the radio in the dash. [ Kenneth  Mar 11, 2020 ]
You always need more power and Apline has made it easy to to pack it in my dash with the stereo. [ Eric  Feb 27, 2020 ]
I have in my jeep wrangler the radio alpine ilx-w650 [ SERGIO  Nov 05, 2019 ]
fits my alpine iLX-W650 [ Andrew  Oct 13, 2019 ]
Need the added power and it bolts right on to the back of the receiver that I purchase along with this amp [ Thomas  Aug 28, 2019 ]
limited space to mount conventional amp in 68 mustang convertible [ Robert  Aug 12, 2019 ]
Because this product cover my necessities about my sound system increases the power and is very compact [ Eduardo  Jul 11, 2019 ]
You dont go to McDonalds and NOT get a large fry. [ William  Jul 06, 2019 ]
great reviews [ FRANCISCO J  Jun 14, 2019 ]
To match with the Alpine headunit. [ Russell  Apr 11, 2019 ]
Direct compatibility with iLX-W650 head unit. [ MICHAEL J  Mar 07, 2019 ]

15 questions already asked

I have a 2016 370z without bose and I got the alpine w650, will I need to hook the amplifier to the battery or does my car make enough power through the head unit?
[ Ethan  Jul 12, 2020 ]
3 answers
Yes, you'll need to direct wire it to the battery. It's a little frustrating in that there is no power indicator light on the unit to ensure it is working.
[ Jay  Jul 13, 2020 ]
You have to hook it up to the battery.
[ Sergio  Jul 13, 2020 ]
I have one connected to the car radio power and it is working just fine, for me the Car 12v is enough power for both radio and amplifier you can try if it yours needs more power then you can add the line from the battery Good luck
[ FRANCISCO J  Jul 12, 2020 ]
I Have a 2000 toyota tacoma in which I got the alpine ilx-w650. New jbl side speakers and the jbl under seat sub. If I add this amp will I have to upgrade the electrical wiring and/or alternator?
[ A.J.  Jun 28, 2020 ]
4 answers
Mines in a 2006 Ram with a Cummins I had no issues with anything in truck since install!!
[ SHAWN  Jul 07, 2020 ]
In my 2005 Tundra, using this same head unit with good component speakers in the doors and a 10" shallow sub in a box behind the seat, I am using all stock wiring and alternator with no issues. I did purchase the amp wiring kit for the KTA-450 also, even though it would probably be fine to run it off the stock power in the dash, it's not hard to set it up right.
[ Joe  Jun 28, 2020 ]
No it should plug directly into factory wiring. Works great. Call the hotline if you need help they are Awesome at answering questions.
[ Troy  Jun 28, 2020 ]
I don't think so I have a very similar setup in my truck and Ive never had power issues that amp is super tiny so current draw doesn't seem to be an issue
[ Shawn  Jun 28, 2020 ]
Will this mount behind an Alpine ILX-107 with the included bracket?
[ Danny  Jun 11, 2020 ]
1 answer
if the size of the head unit is the same it should. I have a ILK-w650 and it is the same . very compact and fit right into the factory dash opening. Maybe check with Alpine?
[ robert  Jun 11, 2020 ]
I have ilx 650 headunit and want to add the kta 450 amp that goes on the back of the headunit i already have a 2000 watt amp for my subs and a secondary battery for power and I did the big 3 upgrade will this amp help my 4 car speakers sound more clear and do I need additional wiring?
[ DWAYNE  Jun 10, 2020 ]
4 answers
It would definitely Help your speakers It makes them more clear but I would make sure behind the head unit the amp will have air flow through there it can over heat easily. I mounted it to the back and I would make sure you upgrade your door speakers. The stock ones sound horrible afterwards .
[ Kathleen  Jun 10, 2020 ]
Pretty sure the 650 is the shallow mount designed for the 450 amp to rear mount with the included bracket. It's very easy and works spectacularly well for what you are describing
[ Michael  Jun 10, 2020 ]
I have this unit installed in my Crown Victoria and am pleased with it's performance. The kta450 fits nicely behind the head unit and really helps the balance of front speakers and the Kicker sub in back. The wiring is straight forward and is compact. I would recommend having a dedicated power feed to this unit. I used the for mine.
[ Eric  Jun 10, 2020 ]
Hey DWAYNE A. I love the clarity of the KTA-450. It's pure, clean, beautiful sound whether thumping at high volume with the bass boosted or low-volume acoustics. I truly never knew what high fidelity was until I installed this. If there are any flaws in your soundtracks be prepared to hear every single one. I did need to wire it to my car's battery. You can probably tap power from either your primary or secondary battery. Crutchfield sold me everything I needed.
[ Clary  Jun 10, 2020 ]
Can this be used with the stock head unit in a 2018 Toyota Tacoma?
[ David  May 05, 2020 ]
1 answer
Yes, that has speaker level inputs to be used with a factory head unit.
[ Cosmo  May 27, 2020 ]  Staff
Can I install it with the factory receiver? I have an 07 Acura TSX. Thanks.
[ J  May 03, 2020 ]
1 answer
Not certain, It's specifically designed for the Alpine head unit. It would probably be fairly easy to wire it but you'd have to modify the brackets or mount it somewhere else
[ ERIC  May 03, 2020 ]
The number on the dipswitches are upside down. Just want to make sure up position on a dipswith its towards the top of the amp?
[ Thomas  Apr 24, 2020 ]
3 answers
I just wanted to chime in and say that the top of the amp is the "up" direction for the dip switches and the numbers are the downward direction for them
[ Paul  May 17, 2020 ]  Staff
Yes, the switch numbers are upside down and "up" means that the switch is in the position closest to the top of the amp. All in the manual that is a poster size sheet folded up like an old road map.
[ DANIEL  May 06, 2020 ]
I went with the orientation of the numbers, if I remember correctly. I agree this is one place where they failed. The markings on the amp and the instructions in the book are inadequate.
[ billy  May 05, 2020 ]
Dip switch settings; which way is up? Is up on or off?
[ Brian  Dec 09, 2019 ]
1 answer
I believe that there is a picture in the manual. But if I remember correctly "on" should be towards the front of the vehicle if attached to the head unit.
[ James  Dec 09, 2019 ]
Why can you not use this with a vehicle that has a factory amplifier? Can you not just bypass the factory amp?
[ Dougs  Sep 10, 2019 ]
1 answer
Hi Douglas, thanks for your great question! If the stock system is built the right way, then yes, you could bypass the factory amp, but we will have to check your vehicle information out and take a look at how your vehicles factory system is built. Please reach out to an Advisor by online chat, or by phone at 1-800-324-9695. They will be able to take a closer look at that for you to see if it would be a possibility for you.
[ Jess  Oct 09, 2019 ]  Staff
I'm thinking of buying this to pair with my iLX-W650, but I have a question about powering it. I understand that the recommendation is to run dedicated wires for power and ground, but if I use the power that is already there, what requirements are there? I currently have a 15A fuse at the battery for audio. Would that suffice?
[ Cue8Chalk  Aug 05, 2019 ]
2 answers
I supplied power to the amp by running a hot wire directly to the battery. Crutchfield sent an amplifier wiring kit when I purchase the KTA-450. I don't remember what the minimum fuse rating is on the KTA-450. Of course if you use a 15 amp fuse and it's not enough, it will blow the fuse when you turn the volume up. I am sure Crutchfield will be able to tell you the minimum power requirements for the KTA-450.
[ ERNEST  Aug 19, 2019 ]
Alpine recommends a 20-amp fuse for power, as close to the battery as possible. Most factory wiring will not handle the amperage that this amplifier will consume. I ended up not installing this amp and instead installed my JL HD900/5 with 4-GA power and ground wiring.
[ Robert  Aug 19, 2019 ]
Will the power stack bracket work w/ non-Alpine head unitsâ??Kenwood Excelon KMM-X503 for instance?
[ BriGuy  Jun 19, 2019 ]
2 answers
I am under the impression that it will only fit to Alpine head units.
[ Timothy  Jun 28, 2019 ]
I don't think so
[ Gilbert  Jun 28, 2019 ]
Can it be bridged as a two channel amplifier?
[ J  May 23, 2019 ]
2 answers
I called Alpine directly and they confirmed the amp CAN be bridged.
[ NSTALN  Aug 25, 2019 ]
Alpine/Crutchfield doesn't provide specs for bridging, so I'd say no.
[ Jay  May 23, 2019 ]
Do I have to connect this to a ground and the battery, or does the supplied adaptor take care of that?
[ Thomas  Apr 07, 2019 ]
1 answer
We recommend running a dedicated power and ground wire for the amp for better stability and performance. Technically you don't have to. The amp is capable of using the same power circuit as the radio.
[ Cosmo  Apr 18, 2019 ]  Staff
If I buy this and mount behind the ilx-w650, is there an alpine adapter/harness to connect the two, or do I just use the rca outputs or speaker level outs?
[ Dave  Mar 26, 2019 ]
2 answers
The KTA-450 has four RCA inputs to match the W650's RCA line outs. You can, of course, cut off the RCA jacks and connect to the speaker leads on the W650
[ GEOFFREY  Mar 26, 2019 ]
RCA connectors that are provided. They are color coded for your convenience. Very easy to install.
[ Timothy  Mar 26, 2019 ]

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