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Alpine PDX-F4

4-channel car amplifier — 100 watts RMS x 4

16 Reviews | 6 questions - 16 answers


Our take on the Alpine PDX-F4

The PDX-F4 4-channel amplifier delivers 100 watts per channel to your speaker system from its amazingly compact body. You can also switch to 2-channel mode, and drive a couple of subs with 200 watts each. Beefy internal components and clever engineering keep the power output strong and the noise low for superb fidelity and control. The adjustable frequency filters tailors the amp's output to your specific system.

Alpine Authorized Online Dealer

Huge digital power comes in a tiny package

Alpine packs Class-D amplifier technology into their PDX amplifiers for awesome power from a 2" tall frame. These small-but-mighty amps run so cool they can be stacked together into a single unit — their heatsinks couple together to cool the entire stack. Each amp offers an 8" by 10" footprint, so they'll fit in hatchbacks, trunks, truck cabs, and any vehicles with limited space.

4-channel powerhouse

The PDX-F4 4-channel amplifier delivers 100 watts per channel to your speaker system from its amazingly compact body. You can also switch to 2-channel mode, and drive a couple of subs with 200 watts each. Beefy internal components and clever engineering keep the power output strong and the noise low for superb fidelity and control. The adjustable frequency filters tailors the amp's output to your specific system.

Front-mounted controls and pop-out connectors

Front-mounted controls make post-installation adjustments a snap, even when multiple amps are stacked together. Nifty removable speaker and power wire plugs make it easy to install or remove an amp, while ensuring a tight connection and guaranteeing that your speakers work in unison. Gold-plated RCA inputs, outputs, and power connections resist corrosion and signal degradation.

PDX-F4 connections

This is a replacement for an Apine 80W 4Ch Amp I bought in 87, still works, just thought she served her time.. A friend is using my old Alpine Head Unit I bought 9 years ago.....Cd player still works. Happy with Alpine

Mark G., Lincoln Park, MI

What's in the Box:

  • 4-Channel class-D amplifier (with two 30A ATO fuses inserted in chassis)
  • Battery connector plug
  • 4 Speaker connector plugs
  • Four M4 x 36mm self-tapping screws
  • 2 Hex-keys (Small/Large)
  • Owner's Manual (Eng/Fre/Spa)
  • Verification Certificate
  • Limited Warranty Card
  • Customer Care Registration Card

Product Highlights:

  • 4-channel car amplifier
  • 100 watts RMS x 4 at 4 ohms (100 watts RMS x 4 at 2 ohms)
  • 200 watts RMS x 2 in bridged mode (4-ohm stable in bridged mode)
  • CEA-2006 compliant
  • stackable installation design with front-panel controls
  • variable high- and low-pass filters (30-400 Hz, 12 dB/octave)
  • quick-connect speaker connectors
  • Class-D amplifier design
  • MOSFET power and output stages
  • fuse rating: 30A x 2
  • 4-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 10-1/8"W x 2"H x 8-9/16"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

Alpine PDX-F4 Reviews

Average Customer Review(s):

(16 Reviews)

Alpine PDX-F4 100W 4Ch Amplifier

Mark G. from Lincoln Park, MI on 6/29/2016

Crutchfield Customer Review (What's this?)

This is a replacement for an Apine 80W 4Ch Amp I bought in 87, still works, just thought she served her time.. A friend is using my old Alpine Head Unit I bought 9 years ago.....Cd player still works. Happy with Alpine

Pros: Works as advertised :

Cons: Narrow range on gain adjustment


Juz10 from Vermont on 9/5/2015

Crutchfield Customer Review (What's this?)

I bought this amp to install in my new car. I had a JL Audio amp in my last car, but thought I would try something new. From day one, I struggled to get good sound from this amp. This amp sounded kind of decent while playing classical, pop, hip-hop and country, but this amp hated heavy metal (which is what I primarily listen to). I found myself constantly skipping songs because they didn't sound good. Music lost it's definition, dynamic range and sounded clipped and compressed. I checked every connection and tweaked every knob in my system for two months trying to find the sweet spot. Today, I bit the financial bullet and swapped the PDX-F4 out with a new JL Audio amp; I just found out what the problem was. I was blown away by the instantaneous improvement in sound! Sorry Alpine, but I don't think I will be dropping any more of my money on your amps. I wish I would have returned this amp before it was too late.

Pros: Solid build. Easy install with the plug and play connectors. Never had any electrical noise issues. 119 watts per channel on certificate. Small footprint.

Cons: Only one major con, but it's the only one that matters to me: Sound quality was poor. Price was high, considering sound quality.

Alpine Pdx-f4

Sergio from Tucson Arizona on 8/25/2015

Crutchfield Customer Review (What's this?)

Upgraded my old lightning audio amp with the pdx-f4 and I really like the sound.



PDX-F4 forever

JohnD from Richmond on 11/13/2014




Super clean sound

JP from Raleigh, NC on 12/3/2013

I installed this amp on a 2013 Honda Civic Si, 4 door with Navigation. I removed the front factory speakers and I replaced them with a pair of Alpine SPR-60C. I left the rear speakers connected to the factory head unit and I disconnected the factory subwoofer. Now, I use the amp for the front speakers with a JL Audio CP108LG-W3v3 subwoofer. The four channel amp from Alpine is outstanding, the sound is clean and powerful. The speakers, the sub, and the amplifier work so well all together. The only other amplifier to consider is the new JL XD500/3, which will give you 300 watts for your sub vs. 200 watts from Alpine. I also need to mention that I am using an Audio Control LC6i with a bass remote, since the amp from Alpine does not have a connection for the bass remote. I get the best sound using my iPod. Believe it or not I hear several musical instruments that before were unnoticeable. I listen all types of music, at low and high volume and the amp does not even get warm (it's challenging me!). Buy it with confidence, super high quality product.

Pros: Super clean and powerful sound.

Cons: Expensive. Does not have connection for the Remote Control Bass Knob (RUX-KNOB).

Alpine Rocks!!

Mike K. from Plainfield, Illinois on 11/23/2013

Crutchfield Customer Review (What's this?)

Needed to upgrade the putrid sound system in my 2010 Ford F-150 FX4 Supercab so i went the fast route and added a Rockford Fosgate PBR300X4 Amp and some RF P 165 Comps in front and P 165 Coax in back. Upgrade was just barely OK by my standards but i wanted more! So...i replaced all the RF stuff with some Alpine Spr 60 comps in front and Alpine SPR coax in the rear along with the Alpine PDX F4 amp! What a HUGE difference in sound! I also added the AudioControl LC7i and a Kicker Hideaway powered sub the round out the system. All i can say is i am amazed at the sounds coming from the system every time i fire it up! It was professionally installed and boy am i glad i went this route because the tech did a perfect job with the install! The Alpine PDX F4 Amp added the much needed punch and clarity that was lacking with the lesser RF setup! The difference was so big it was like night and day! I crank my music every chance i get and the amp just gets a little warm! The amp is hooked up under my back cab seats along with the Kicker Hideaway and i have the AudioControl under the drivers seat for easy access to all of my pieces for fast tuning. Yes the Alpine amp is pricey but it is so worth the money if you love music like i do!

Pros: Kicks out some HUGE clean sound!

Cons: Does not come with Kate Upton!

Excellent Amp for the Money

Rick from Minneapolis on 11/11/2013

Crutchfield Customer Review (What's this?)

Great amp for the price. It's not a class A amp, but compares very favorably to other class D power. Has all the bells and whistles, too. Very satisfied.

Pros: Price. Features. Power.

Cons: It's not a class A amp, but the price is much lower.

Best amp out there

CarolinaSounds from Charleston sc on 7/18/2013

I bought this amp about a year ago. I have it powering a pair of type r 6 components and the other two channels bridged to a single 4ohm 12. I can't tell you how many people go wow how many woofers and door speaker sets do you have?! I tell them one.amp.and they go what?! Very clear and doesnt pull power from battery/alternator to speak of. I have had jl Rockford and alpine before, I like this the best.

Pros: Clean and compact

Cons: Non


Mike from Snohomish, WA on 6/22/2013

Crutchfield Customer Review (What's this?)

Very good see pros and cons below

Pros: Straight forward install. More power than advertised. Clean sound. Compact design. Easy install.

Cons: None!

First Fullrange Class D

Rob from Kona, HI on 4/9/2013

This is such a well designed compact piece of equipment. I was skeptical that a class D full range could sound as good as this amp does. It does not get hot and pumps out the sound and is super efficient. The price is pretty steep but the return on your investment is great. The plug in connections along with the tiny size made it the easiest amp I have ever installed. The install instructions could be a little more detailed in regard to phase and bridging.

Pros: Small, efficient, easy plug in power and speaker terminals

Cons: limited x-over section for an amp in this price range but the power output and sound quality will quickly make you forget about the lack of controls

2003 Ford Ranger

Nick from Cincinnati, Ohio on 9/23/2012

Crutchfield Customer Review (What's this?)

I purchased this amp to replace a defective Eclipse amp that I had. i have to say that both the Eclipse amp and the Alpine amp are both up and beyond sounding amps. I did have to connect a line driver up to my Eclipse amp to get the most out of it, the Alpine amp so far, doesn't need one. This amp is very loud on it's own. I'm pushing some 5X7 component Infinity speakers, and at ear level, I'm getting 116 decibels. The amp is only rated for 100 watts rms, the certificate that came with it said it's putting out 118 watts rms. I wish every amp would come with this certificate so it'd be a lot easier to see which amps really perform like they're stated they do. Love the amp, I highly recommend this to anyone who wants sound quality and loudness.

Pros: Everything

Cons: None.

Great Compact Amplifier

Morgan12 from Ellington, CT on 9/1/2012

Crutchfield Customer Review (What's this?)

The PDX-F4 is a great 4-channel amplifier. It delivers amazing sound to a pair of Polk SR5250 component speakers (bi-amp setup). This amp provides plenty of power with 120 watts per channel (birth sheet rating) and fits just right under the passenger seat of my Toyota 4Runner. A bit pricey but worth it for the compact design and Alpine quality. I have owned this amp for two years now and hope to get several more years of listening pleasure out of it.

Pros: Amazing sound, Alpine quality, compact design

Cons: None

Pdxf4+type r components - best

Yianni from Ruckersville on 8/10/2012

Have this powering my type r components and coaxials, crystal clear sound, no random noises, 123 watt RMS birth certificate, best amp I've ever owned even better than my Jo audio slash series. I have it mounted under my seat and still it never gets hot

Pros: Clarity, doesn't get hot

Cons: None

Best amp ive bought by far

ERC from Dallas, tx on 8/7/2012

Great amp, cool design, rated 125w on birth certificate. Running this amp with alpine ida-x305s and infinity reference 6.75 components and these things bump on 125w. People cant believe i dont have subs

Pros: Incredible digital power and bar none flat frequency response. I hear everything! This amp is good for incredibly detailed bass which is hard to come by with most full range amps

Cons: Absolutely none, its an exquisite piece of engineering


2011 sienna le from hawaii on 11/18/2011

124 watt rms on birth sheet. no hiss even with factory stereo. pushes my focal polyglass 165 v30 comps loud and clean. Small, fits under front seat perfect. only gets warm even after hours of running. sounds amazing even though its class d. flawless so far. Have it hooked up with audiocontrol lc6i loc. No Noise issues, no complaints. Just high quality sound.

Pros: 124 watt rms on birth sheet. Small. Clean output. Looks really good. high signal to noise ratio.

Cons: None so far, only had it hooked up a month or so.


ewm234 from Richland, WA on 8/1/2011

This amp is outstanding! The birth certificate in the box states it tested out at 127 watts. I believe it, this thing pushes my alpine 6x8 type R speakers to the limit and I had to turn the gain down to keep them from blowing. The speakers are so loud and clear with this amp its unbelievable! The amp is also so small that it fits perfectly under the passenger front seat of my explorer and nobody knows its there.




Hands-on research

Product Research



PDX Amplifier Design: Class-D amplifiers boast higher efficiency, produce much less heat, and draw less current than traditional Class-AB amps. The PDX series is Alpine's super-efficient power density design of full-range and monoblock class-D amps. They combine MOSFET power supplies, MOSFET final outputs, and a thermal management processor, along with a 6-Layer Glass Epoxy PC Board to create a high-end sound quality without the bulky heat sinks required by most amps with this much power.

STAR Topology: Alpine's unique STAR (Signal Transit for Accurate Response) Circuit PCB design provides a single common ground for all amp sub-blocks, preventing ground interference and minimizing internal noise.

Power Management Processor: The Alpine PDX amplifier incorporates Alpine's new Power Management circuit. The Power Management Processor controls all aspects of amplifier performance, monitoring voltage, temperature and output to ensure uninterrupted power output for non-stop listening.

Uninterrupted Protection Circuits: If the amplifier gets too hot, the Thermal Protection circuit kicks in and gradually decreases output power until it cools down. Once cool, the power output automatically increases back to the previous level. If the circuit detects a Low Battery condition, it will gradually decrease power output if battery voltage becomes too low. Once the battery voltage increases, power will be restored. This interruption-free design allows for non-stop enjoyment with no hiccups or drop-outs, just clean, clear output.

Channel Design: The Alpine PDX-F4 can be configured as a 4-channel, 3-channel, or 2-channel amplifier. The amplifier is stable down to 2-ohms in stereo, and 4-ohms when bridged.

Low Impedance Stability: This amp is stable at low impedances and is capable of its rated power (100-watts x 4-channel) from 2 to 4 ohms. This allows excellent flexibility with multiple speaker and subwoofer loads and is adjusted automatically.

CEA 2006 Compliant: The PDX-F4's power ratings are measured according to the strict standards dictated by the Consumer Electronics Association (CEA). These standards allow you to accurately compare the rated power output of all CEA 2006-compliant amplifiers, even if they come from different brands. Manufacturers who adhere to the standards can display the CEA 2006 logo on their products and packaging.

  • Four-Channel (4-ohm): 100 watts x 4-channel in 4-ohms @ 20 to 20,000 Hz with 1% THD+N
  • Four-Channel (2-ohm): 100 watts x 4-channel in 2-ohms @ 20 to 20,000 Hz with 1% THD+N
  • Bridged (4-ohm): 200 watts x 2-channel in 4-ohms @ 20 to 20,000 Hz with 1%

Verification Certificate: The amplifier comes with a certificate that lists the RMS power output of the individual amplifier. It also lists the model number, serial number, test date, and the test conditions (14.4 volts, 4 ohms).

Ultra-Wide Frequency Response: The Alpine PDX-F4 offers a super-wide, frequency range (5Hz-100kHz) for unparallel sound quality and detail.

Ultra-Low Output Impedance: With ultra-low output impedance, the PDX-F4 offers extremely controlled, tight bass for unprecedented sound quality. The amplifier's Damping Factor is rated at >500.

High Signal-to-Noise: This amplifier is capable of S/N ratios up to 95dB S/N @ 1W, 115dB S/N at rated power for extremely clean, uncolored sound. The PDX amp delivers crystal clear music every time, without unwanted background noise or static.

Beefy Power Supply: The PDX amplifier's power supply delivers tremendous headroom with low distortion and noise. The PDX amplifier has an extremely high total system efficiency of ~80% (power supply is rated at >90%, output stage is rated >90%).

Stackable: The PDX series amplifiers are 20% thinner than previous models at only 2" thick. A newly designed stacking system packs the amps closer together so there are no gaps and to save space in the trunk while directly coupling the amps heatsinks to help share cooling duties.

Notes: When stacking multiple amplifiers, do not install vertically or at an incline. Any stack installation other than parallel to the vehicle floor, invalidates the warranty.

LED: The top mounted LED Power indicator glows blue when the amplifier is turned on.


Hidden Controls: The Alpine PDX amplifier's controls are hidden behind a decorative front-panel. The front-panel is removed by unscrewing one machine-screw with the supplied hex-key and then prying the front-panel open.

Gain control: The PDX-F4 provides independent rotary controls for the front and rear channels to set the amplifier's gain according to the level of the incoming signal. The gain settings is continuously variable from 0.2V to 4.0V.

Crossover Mode Switch: The Alpine PDX-F4 offers independent crossovers for the front and rear channels. Each crossover can be set to HP (high pass), OFF (full range) or LP (low-pass).

Crossover Frequency: You can independently select the crossover frequency for the front and rear channel crossovers. The crossovers are variable from 30 to 400Hz (-12 dB/oct).


Terminal Layout: For wiring convenience, all of the inputs and outputs on the amplifier are on one side.

Quick Connect Plugs: The PDX series amplifier uses quick connect plugs to attach your system's speaker wires and power cables to the amp for a simple, error-free installation.

Quick Connect Speaker Terminals: The Alpine PDX-F4 includes four quick connect high-power speaker terminals. Bare speaker wire, up to 8 gauge, is held in place by screw-clamps on the quick connectors. The four speaker terminal quick connectors then plugs into the amplifier.

Quick Connect Battery Terminals: The removable battery terminal quick connector features a low-loss, high-current design. It accepts up to 4GA wire for power and ground, to ensure your amp gets the power it needs while allowing for easy installation. The remote-turn on lead will accept up 12 gauge wire. The power, ground, and remote-turn on lead are secured by set-screws on quick connector. The battery terminal quick connector then plugs into the amplifier.

Line Level Input: The Alpine PDX-F4 is equipped with four gold-plated female RCA jacks.

Fuses: The Alpine PDX-F4 is equipped with two 30-amp ATO fuses.

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 verify what’s in the box, 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.

Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

This is to replace a alpine 80w/4ch amp I bought in 86...Recently bought am alpine 600 sub amp and a 10 rockford fosgate spk... I am happy with alpine and I take my music seriously....My buddy is using my alpine head unit I bought 9 years player still works.... [ Matthew  Jun 12, 2016 ]
Very powerful amplifier. Definitely packs a punch for its small size. [ CHRISTOPHER  May 03, 2016 ]

6 questions already asked

I do not recommend it. Its a great Amp but not for that. [ Timothy  Jun 12, 2016 ]
No, it should not be loaded at 2 ohms bridged. [ IVAN  Jun 03, 2015 ]
It handles any load because it's a class d [ PIERRE A  May 24, 2015 ]
It should be fine as long as there's enough ventilation [ kenneth  Apr 12, 2015 ]
mine is mounted vertical and has operated fine for a couple years. [ MIKE  Apr 12, 2015 ]
I mounted mine vertically in my single cab pickup, no problems for me! [ Rick  Apr 11, 2015 ]
that bullet point in the manual is specific to stacks. If you are just mounting a single do it how ever you wish. "Stack installation should always be parallel to the vehicle floor - do not install at an incline. such as leaning against a vertical surface as this will invalidate your warranty." [ SCOTT  Apr 11, 2015 ]
You should not have any problems mounting the amp that way. Mine is horizontal but i was going to mount it vertically behind the backseat wall of my pickup. no worries! [ MICHAEL  Apr 10, 2015 ]
I have it hook up to a 200 amp fuse to the battery but I'm running two amps and believe I'm using 0 gauge or whatever thickness gauge u can find. Both amps r pdx though [ PIERRE A  Feb 04, 2015 ]
60 Amp is more than enough.. I run battery cable from the battery to within a couple feet of the amps, I run two Amps off the cables and some other electronics, I have a 140 amp breaker just in case anything shorts out, never been tripped in the many years i have had it. [ Willie  Feb 04, 2015 ]
I used the kicker pkd4 kit with a 100 amp fuse for my system and it works great [ Ryan  Feb 04, 2015 ]
In fact there would be no need to think about the orientation of the speaker output plugs. Since alpine uses the same technique present in RCA interconnects for speaker cable terminals, positive and negative ports are attached to the inner and outer metal joints. So do not consider the positions of speaker plugs. Just be ware of the signs + and - on the terminals, plug them to the amp - in any direction- and you are done. [ Hamed  Jan 11, 2015 ]
If I remember correctly the plugs only went in one way. I love the amp! [ MIKE  Oct 24, 2014 ]
The amp actually does have + - signs on them [ PIERRE A  Oct 22, 2014 ]
As polarity goes, I was told that the center conductor is the positive and the outside conductor is the negative terminal. I own 3 of these Alpine Amps, PDX-F4, PDX-F6 and the PDX-M6, Great Amps and I would purchase again. [ STAN  Oct 22, 2014 ]