About the Alpine KTP-445U Power Pack
More power, less hassle
More power, less hassle
Want a simple way to crank up the power of your receiver? Alpine's "Power Pack" amplifier increases your receiver's power output to 45 watts RMS by 4 channels. That's a big jump up from the 7-20 watts per channel typically put out by a car radio, and plenty of power to drive high-performance speakers or keep up with a big subwoofer amplifier. Best of all, this compact amplifier is so efficient you can often run it off the same circuit that powers your receiver. A universal plug lets you feed a signal via RCA outputs or speaker-level wiring.
You can install this compact amp behind most dashboards, but you'll need 4-channel patch cables to connect your car stereo to the amp's preamp inputs. You can also splice into your speaker wiring to get signal to the KTP-445U.
Installation Note: We recommend running a dedicated constant power wire to the battery for optimal performance from this Alpine amp — we offer an inexpensive wiring kit for this installation. This high-powered amp won't work in systems where an outboard factory amplifier is still active.
- Featured in our article: Best 4-channel car amplifiers for 2023
- compact 4-channel car amplifier
- 45 watts RMS x 4 at 4 or 2 ohms
- 90 watts RMS x 2 bridged at 4 ohms
- CEA-2006 compliant
- Class D amp technology
- selectable high-pass filters (60, 80, or 120 Hz at 12 dB/octave)
- switchable 2- or 4-channel input
- switchable RCA or speaker-level inputs
- fuse: 15A
- dimensions: 7-7/8"W x 1-1/2"H x 2-9/16"D
- warranty: 1 year
- Our 60-day money-back guarantee
- MFR # KTP-445U
What's in the box:
Alpine KTP-445U Power Pack owner's manual
- Head Unit Power Pack
- 15-amp ATM mini-blade fuse (installed)
- 30" Power/speaker-output harness
- 5.5" Speaker-level/low-level input harness (Turn-on lead is 40" long)
- 2 Metal brackets
- 4 Phillips/Hex-head mounting screws
- 4 Wire-ties
- Owner's Manual (English/ French/ Spanish)
- Limited Warranty card
- "Thank You" letter
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More details on the Alpine KTP-445U Power Pack
Features & specs
|RMS Power Output (Watts x Channels)||
45 x 4 |
|Peak Power Output (Watts x Channels)||90 x 4|
|Power at 2 Ohms (Watts x Channels)||45 x 4|
|Bridged Power (Watts x Channels)||90 x 2|
|Minimum Impedance Bridged||4|
|Minimum Impedance Unbridged||2|
|Best Frequency Response||20-20k Hz|
|THD at Rated RMS Power||1%|
|Signal to Noise Ratio||82 dB|
|Low-Pass Crossover Frequency||N/A|
|Low-Pass Slope (dB/octave)||N/A|
|High-Pass Crossover Frequency||60, 80, 120Hz|
|High-Pass Slope (dB/octave)||12 dB/oct|
|Bass Boost Frequency||N/A|
|Speaker Level Inputs||Yes|
|Parts Warranty||1 Year|
|Labor Warranty||1 Year|
Overview: The Alpine KTP-445U Head Unit Power Pack is a power upgrade amplifier that allows you to add higher output and more dynamic response to your aftermarket or factory installed car stereo system (without factory amplifiers). The KTP-445U amplifies your aftermarket or factory head unit's power output, resulting in increased power over the original head unit's built-in amplifier. It's small and compact at only 7.875" (w) x 1.5" (h) x 2.5625" (d) and fits behind the head unit in the dash of most vehicles. The KTP-445U comes equipped with RCA and auto-sensing speaker level inputs.
- If the fuse protecting the OEM radio is less than 15 Amps, you should run a separate +12V constant power wire from the battery to the higher-powered Alpine KTP-445U.
- This Alpine high-powered amp won't work in systems where an outboard factory amplifier is still active. If used in vehicles with a factory amplifier, the factory amp will need to be completely bypassed (this may result in lost speaker channels, if factory amp has more than 4 channels).
- The increase in power may result in a louder warning chime in certain vehicles.
45 Watt x 4 Channel Amplifier: The Alpine KTP-445U Head Unit Power Pack employs a 45 watt x 4 channel amplifier. The amplifier offers an unbelievably low noise floor, taking extra care to ensure a clean signal path, with no extraneous interference. The end result is a 1 Watt Signal-to-Noise Ratio of 82dB or better. Uniquely, the amplifier distortion actually decreases at higher frequencies, resulting in a clean and clear signal where your ear is most sensitive to distortion (< 0.03% THD+N @ 1W; 1% THD+N @ rated power).
CEA-2006 Compliant: The specifications given by Alpine for the built-in amplifier comply with the CEA-2006 mobile amplifier power testing and measurement standards from the CEA (Consumer Electronics Association). All manufacturers who comply with the standard can display the CEA-2006 logo on their product.
- CEA-2006 Power Rating: 45 watts x 4 channels (at 4/2-ohms, 20-20kHz, 1% THD)
- Bridged: 90 watts x 2 channels (4-ohm minimum impedance)
- Max Power Output: 90 watts x 4 channels (Peak)
Controls: The Alpine KTP-445U Head Unit Power Pack provides independent controls for the Front & Rear inputs.
- Front & Rear Gains: The Power Pack provides simple variable gain controls (speaker level: 0.5-10V, low-level: 0.2-4V) for flexibility and a wide variety of system applications.
- Front & Rear HPF: High-Pass selectable switches for the amplifier's Front & Rear inputs allow frequency filtering for a wide variety of speakers. Choose "Full-Range" or a selectable range (60Hz, 80Hz, 120Hz) to fine-tune your crossover points (-12dB/oct.).
- Configurable Inputs: On the bottom panel of the Power Pack there are selectable input options to accommodate Speaker-Level (0.5V-10V) or RCA (0.2V-4V) inputs.
- 4Ch/2Ch Modes: Selectable 2-Channel & 4-Channel options give you the control to determine source inputs, and can eliminate the need for Y-adapters.
Low-Level & Speaker Level Inputs: The Alpine KTP-445U Head Unit Power Pack includes a 5.5" low-level/speaker-level input harness. The harness features a proprietary 10-pin connector on one end that plugs into the KTP-445U and two pair of stereo RCA inputs that connect to your source unit's front & rear RCA outputs using a pair of stereo RCA cables (sold separately). If your source unit is not equipped with RCA outputs and only features speaker-level outputs, then you can cut off the included low-level/speaker-level input harness' RCA connectors (or use the optional Speaker Wire to RCA Adapters) and connect the KTP-445U to your source unit's front & rear speaker outputs.
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 connecting the KTP-445U via Low-level (RCA). You do not need to connect the remote turn-on lead wire when connecting the amplifier via speaker-level input, because the speaker-level inputs are auto-sensing.
Power/Speaker Output Harness: The Alpine KTP-445U's power/speaker output harness consists of a 16-pin proprietary connector on one end that plugs into the KTP-445U, and bare wires on the other end to connect to power/ground and your car stereo speakers through your vehicle's factory or aftermarket head unit's wiring harness. (What looks like a fuse holder in-line with the amp's power wire is actually a noise filter.)
Note: The factory radio circuit needs to be a minimum of 15A. If it is not, a separate power and ground will need to be installed for the KTP-445U.
Mounting: The Alpine KTP-445U Head Unit Power Pack includes cable ties to attach the amplifier to your vehicle's frame or chassis. The KTP-445U also includes two mounting brackets and four hex-head screws to fasten the amplifier to a flat surface of your vehicle.
117 questions already asked
This little amp is just what the Doctor ordered, small but yet powerful & very clean sound. I paired it with a new Alpine CDE-122 head unit with some new JBL 5 1/4" coaxials, what a difference. I already had a amp/sub in the trunk so this update really blended everything great!
David R from Lewisburg, WV