Skip Navigation

Pioneer GM-A6704

4-channel car amplifier — 60 watts RMS x 4

24 Reviews | 4 questions - 7 answers

Overview

Our take on the Pioneer GM-A6704

Why put an amplifier in your car? Pioneer's GM-A6704 4-channel amplifier will greatly improve the sound quality in your vehicle, so you'll find yourself looking forward to your time on the road. This punchy Pioneer will power your front and rear speakers with 60 watts RMS each, which is a large jump over the power supplied by a typical car radio. You'll hear much more of the little details in your music, especially when you turn your system up to overcome road noise.

Plays loud and clear

Why put an amplifier in your car? Pioneer's GM-A6704 4-channel amplifier will greatly improve the sound quality in your vehicle, so you'll find yourself looking forward to your time on the road. This punchy Pioneer will power your front and rear speakers with 60 watts RMS each, which is a large jump over the power supplied by a typical car radio. You'll hear much more of the little details in your music, especially when you turn your system up to overcome road noise.

4-channel versatility

Here's why lots of people start building their systems with a 4-channel amp. You can run your front speakers with the front channels (A) on this Pioneer, then combine the rear channels (B) to drive a subwoofer. Then, when you've got enough cash to buy a second sub and a dedicated amp for your bass, you can use your 4-channel to run all your speakers. You can also put this versatile amp into 2-channel mode to send up to 190 watts RMS each to a couple of component speakers or subwoofers.

Practical features

The front channels sport variable high-and low-pass filters so you can better adjust the sound for critical front soundstaging or a finely-tuned bass. Switchable high- and low-pass filters on the rear channels help take the rumble away from full-range speakers or the sizzle away from a sub. A bass boost adds extra kick, if you want it. Speaker-level inputs allow you to add the GM-A6704 to a factory system. If your vehicle needs a sonic upgrade, this amp's performance features and reasonable price make it a great choice.

Product Highlights:

  • 4-channel car amplifier
  • 60 watts RMS x 4 at 4 ohms (95 watts RMS x 4 at 2 ohms)
  • 190 watts RMS x 2 in bridged mode (4-ohm stable in bridged mode)
  • CEA-2006 compliant
  • variable high-pass (40-500 Hz, 12 dB/octave) and switched low-pass (80 Hz, 12 dB/octave) filters on A channels
  • switchable high- and low-pass filters (80 Hz, 12 dB/octave) on B channels
  • switchable bass boost (0, 6, 12 dB at 50 Hz) on B channels
  • preamp and speaker-level inputs
  • fuse rating: 25A x 2
  • 8-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 14-1/4"W x 2-3/8"H x 8-1/2"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

What's in the Box:

  • 4-Channel amplifier
  • Two 25A ATO fuses (installed)
  • Speaker-level input harness with eight 4" wires
  • 4 Self-tapping screws (3/4" length)
  • Owner's Manual (Eng / Fren)
  • Owner's Manual (Span)
  • Warranty sheet

Great appearance, light weight, super easy to install, clear instructions and the whole system sounds great. This amp is powering four component speakers and I'm using infinity crossovers. Replaced the factory Mach 460 system.

Rich, Ellicott City, MD

Reviews

Pioneer GM-A6704 Reviews

Average Customer Review(s):

(24 Reviews)

Pioneer GM-A6704

Crutchfield customer from Oliver Springs, TN on 12/23/2018

Crutchfield Customer Review (What's this?)

Installation was not so easy in my truck, but the staff at crutchfield made it a whole lot easier. Called them multiple times when I hit a snag.no big box store can or would do that. Thanks guys.

Pros:

Cons:

Pioneer GM-A6704

Crutchfield customer from Chino Hills, CA on 12/1/2018

Crutchfield Customer Review (What's this?)

Shipped quickly and looks good. Can't give 5 stars yet because It won't be installed in my boat until January.

Pros:

Cons:

Pioneer GM-A6704

Crutchfield customer from Las Vegas, NV on 11/24/2018

Crutchfield Customer Review (What's this?)

Originally tried to power speakers (JBL club series) with power from kenwood deck....sounded OK, but distorted when I turned the volume up. After installing the Pioneer amp the sound is much more clear and full especially at the higher or upper end (of the volume). This amp makes the speakers sound so much better.

Pros: Easy to install

Cons: None

Great upgrade from factory system

Rich from Ellicott City, MD on 10/12/2018

Crutchfield Customer Review (What's this?)

Great appearance, light weight, super easy to install, clear instructions and the whole system sounds great. This amp is powering four component speakers and I'm using infinity crossovers. Replaced the factory Mach 460 system.

Pros: Light weight, easy install, clear instructions, clean powerful sound

Cons: None yet

Great sound easy installation

Jeff from Waynesboro, VA on 9/19/2018

Crutchfield Customer Review (What's this?)

The improvement is dramatic. I enjoy my drive now.

Pros: Easy to install

Cons: Tuning instructions are not the greatest

Awesome device

Crutchfield customer from Philadelphia, PA on 8/12/2018

Crutchfield Customer Review (What's this?)

I have this amp powering two 6x9's and two 6-3/4 pioneer speakers. They power them perfectly. Sound is super clear. I also have two subs powered by a second amp. Without the subs the ones powered by this amp still sound great.

Pros: Great product.

Cons: Haven't found any.

Pioneer GM-A6704

Crutchfield customer from Lansford, PA on 8/9/2018

Crutchfield Customer Review (What's this?)

easy install and great sound...

Pros:

Cons:

Pioneer GM-A6704

john from Victor, NY on 7/31/2018

Crutchfield Customer Review (What's this?)

clear and powerful amp . Directions should tell you need to wire the remote wire to work ,though.

Pros:

Cons:

Would recommend

Patrick from Beaumont, TX on 3/21/2018

Crutchfield Customer Review (What's this?)

Overall great product. Does what it is supposed to do without producing too much heat like other amplifiers I have used have done. Would recommend.

Pros:

Cons:

Pioneer GM-A6704

Crutchfield customer from Rathdrum, ID on 3/5/2018

Crutchfield Customer Review (What's this?)

Awesome sound. Some would say the pioneers are not as good as some of the others but with the right set up it's just as good as you can get.

Pros:

Cons:

Great Amp!

Crutchfield customer from Dunnellon, FL on 3/3/2018

Crutchfield Customer Review (What's this?)

Easy installation and great clean sound. Love it!

Pros:

Cons:

Pioneer GM-A6704

Daniel from Austin, TX on 2/4/2018

Crutchfield Customer Review (What's this?)

Solid product. Good clean power. Very satisfied.

Pros: Good clean sound.

Cons: None

Pioneer GM-A6704

Crutchfield customer from Lakewood, CO on 1/8/2018

Crutchfield Customer Review (What's this?)

Installed easily and the speakers sound great.

Pros:

Cons:

Pioneer GM-A6704

Crutchfield customer from Troutville, VA on 12/17/2017

Crutchfield Customer Review (What's this?)

????

Pros:

Cons:

Pioneer GM-A6704

Ausencio from Online on 9/25/2017

Crutchfield Customer Review (What's this?)

Good product.

Pros:

Cons:

Good amp for the price

Dusty from Athens, GA on 9/18/2017

Crutchfield Customer Review (What's this?)

Works great to power two coaxials at 60w each and a sub at 190w. Gets warm so make sure to have it properly ventalated.

Pros: Works as it should

Cons:

Pioneer GM-A6704

Charles from Gresham, OR on 9/11/2017

Crutchfield Customer Review (What's this?)

This is great amp is working great with my pioneer ach 2330-nex. Installed with Kicker 43CSC654 & Kicker 43CSC6934 great sound easy adjustments.

Pros: None

Cons: None

Pioneer GM-A6704

Crutchfield customer from Chicago, IL on 7/26/2017

Crutchfield Customer Review (What's this?)

Great Amp. Easy to set up.

Pros:

Cons:

Pioneer GM-A6804

Bill from Sylacauga, AL on 7/11/2017

Crutchfield Customer Review (What's this?)

Packs A Punch On 2 Kicker 6x9 And 2 Kicker 6.5 awsome power plenty and very loud

Pros: Runs great plenty of power ran it 5 hrs straight never broke a sweat ran 4 kicker speakers with it turned up only half way easy adjustments for side A and Side B speakers balanced out perfect customer was very happy

Cons: None

Pioneer GM-A6704

Crutchfield customer from Northville, MI on 6/16/2017

Crutchfield Customer Review (What's this?)

This amp is exactly what I was looking for to power my speakers. I love the versatility of combinations of channels. I am using it as a 4 channel speaker amp to power a component set in the front and a coaxial pair in the back. You could also run a speaker set on Channel A and a subwoofer on Channel B. With separate gain controls and a bass boost for Channel B you can completely separate the setting between Channel A and B as if you were using 2 amps. Channel A also has a Variable HPF adjuster so I can tune those tweeters in just right. My favorite thing is the speaker signal connector. It eliminates the need for a remote wire and it makes for an incredible sound stage. I've never had an amp that creates a surround system atmosphere like this one. A drum roll literally circles my car. This is all with it hooked to a factory head unit. I can only image how its going to sound when I install a new head unit.

Pros:

Cons: When it starts to get hot it will send less power until to cools off. Not a big deal but you can hear the music get soft every once in a while on a long drive.

Powerful amp!

Jason from Brooklet, GA on 5/15/2017

Crutchfield Customer Review (What's this?)

Pushes my Pioneer component system and rear door speakers with no problems. Really brings out the speakers performance!

Pros:

Cons:

Pioneer GM-A6704

Mario from Denver, CO on 2/21/2017

Crutchfield Customer Review (What's this?)

Works great with my Kenwood ddx9902s. You a real clear sound through my kicker speakers.

Pros: Very good and clear sound

Cons: Too big to fit under the seat or dash. It's more for a trunk not a small pick-up

Pioneer GM-A6704

Doug from Lodi, CA on 2/20/2017

Crutchfield Customer Review (What's this?)

Great value. Crisp, clean sound. Plenty of punch.

Pros: Power. Clear sound field. Value.

Cons: None

Great amp for the price, Pioneer quality.

Scott from Parkton, MD on 12/27/2016

Crutchfield Customer Review (What's this?)

Really good amp. Love the ability to use the amp to fine tune my speakers for bass, and volume front to rear while leaving the stereo setups in factory center. Used 2 of these in vintage car applications with front Retro sound center speaker and 2 rear Polk 6x9's. Lots of drive for these speakers from this amp.

Pros: Adjustablility, good sound and power.

Cons: Smaller footprint for tight spaces would be appreciated.

Details

Hands-on research

Product Research

Features

CEA-2006 Compliant: CEA-2006 is a system of testing and measurement methods 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 power uses a DC input voltage of 14.4 volts and the RMS power output is measured into a 4Ω load, with 1% or less Total Harmonic Distortion plus noise (THD+N), and over a frequency range of 20 Hz to 20 kHz (for full range amplifiers). Signal-to-Noise ratio is measured in weighted absolute decibels (dBA) at a reference of 1 watt into 4Ω. CEA-2006 standards allow consumers to compare amplifiers on an equal basis. Using CEA-2006 criteria, the Pioneer GM-A6704 is rated at 60 watts RMS x 4 channels, with a 78 dBA signal to noise ratio.

Specifications: The manual also lists these non CEA-2006 compliant specifications:

  • Power:
    • 2Ω: 95 watts x 4 channels (14.4 volts, 1 kHz, no more than 1% THD+N)
    • Bridged: 190 watts x 2 channels (into 4Ω, 14.4 volts, 1 kHz, no more than 1% THD+N)
  • Signal to Noise Ratio: 95 dB (at rated power)

Gain Control: To accommodate the varying range of signal levels coming from today's factory and aftermarket radios, the input gain is adjustable (0.3V-6.5V line level, 3V-26V speaker level). The front (Channel A) and rear (Channel B) inputs have separate gain controls.

LPF/HPF: The amplifier has independent crossovers for the front (Channel A) and rear (Channel B) outputs. Each crossover can be set to LPF (Low-Pass Filter), HPF (High-Pass Filter), or Off (All-Pass). The crossover point for the high-pass filter on Channel A is variable between 40Hz and 500Hz, adjustable via a rotary control. The crossover point for high-pass filter on Channel B and both low-pass filters is fixed at 80Hz. The slope for all crossovers is 12dB/octave.

Bass Boost: The GM-A6704 has a selectable bass boost at 50 Hz for the rear channels (Channel B) only. You can set the boost at 0dB, +6dB, or +12dB.

Power Connections: The power and ground connections are 0.54" wide screw terminals, the remote turn-on screw terminal is 0.325" wide. A Phillips-head or flat blade screw driver (not included) is required to tighten/loosen the terminals. With a total fuse rating of 50 amps, 8 AWG power and ground wire is recommended. A 50A fuse should be placed on the power wire within 18" of the battery. Spade connectors are recommended for the power, ground, and remote wires.

Speaker Connections: The speaker screw terminals are 0.325" wide. A Phillips-head or flat blade screw driver (not included) is required to tighten/loosen the terminals. Spade connectors are recommended for the speaker wires.

RCA Input: The amplifier features two pairs of stereo RCA line level inputs (Channel A left/right and Channel B left/right). The Input Select switch lets you set the amplifier for 2-Channel or 4-Channel Input. If set to 2-Channel, the input signal from Channel A left/right will be sent to all four channels.

Speaker Input: The included speaker level input harness allows you to connect your OEM radio (or aftermarket radio that does not have the typical RCA-type outputs) without having to buy an adapter. When the speaker input harness is used, the amplifier is set to 4-Channel mode automatically.

Auto Power On: When using the speaker level input, a circuit senses the input signal and turns the amp on automatically. This feature makes it easier to add an amplifier to a factory radio or to a receiver with no preamp outputs.

Fuse: The amp is protected by two 25-amp ATO blade 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.

Accessories
Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

My car is red...amp fits the need and its red [ Drew  Jan 19, 2019 ]
Price, power, and brand name [ Michael  Jan 14, 2019 ]
recommended by friend [ albert  Jan 11, 2019 ]
Always happy with Pioneer products [ mark  Dec 29, 2018 ]
Recommended [ Kevin  Nov 27, 2018 ]
It was recommend by an expert at Crutchfield. Compliments to "Trisha" on the chat room. Gave me what I needed based on what I current have. Everything I have is from Crutchfield so it made things super easy by looking at my purchase history. [ Denmarcus  Aug 07, 2018 ]
I have the Pioneer 4200 nex radio [ patricia  Jun 28, 2018 ]
Grandson requested it for his birthday. [ Gail  Jun 23, 2018 ]
Highest rated, best priced 60 watt by 4 ohm available [ Tony  Jun 16, 2018 ]
why not [ thomas  Mar 04, 2018 ]
More power, better sound [ JEFF  Feb 18, 2018 ]
For compatibility with my head unit and I've been very happy with previous Pioneer purchases [ David  Feb 06, 2018 ]
Great amp for the price. Older son has same amp and he is very happy with it. [ HUSTON  Jan 12, 2018 ]
chat with customer service rep [ Kevin S.  Oct 11, 2017 ]
Need the power [ James  Sep 27, 2017 ]
Exactly what i needed to upgrade, the interface to configure the gain and highs and lows of frequency and what not is simple to understand, and its not ugly looking. [ Ross  Aug 21, 2017 ]
Solid brand solid price [ Tsimafei  Jul 22, 2017 ]
Right amp for what I needed [ Bryan  Jul 17, 2017 ]
Good price for a 4 Chanel amp [ G  Jul 10, 2017 ]
Advisor [ AFEEZ  Mar 14, 2017 ]
Perfect match for my 4 coaxials [ M  Feb 18, 2017 ]
It was recommended by one of your techs [ Mario  Feb 08, 2017 ]
I'm going to be using this in a tri-amped system in the mid-bass/mids and highs. I wanted a class-AB amplifier for this range of frequencies not really knowing what is out there in the car stereo amplifier market. I do know, that the best performing Class-AB designs compared to Class-D designs measure much better (On a distortion analyzer) and are less fatiguing to listen too that even the best Class-D amps. [ Cameron  Jan 16, 2017 ]
My current Alpine just failed, and I weighed the Pioneer that I choose against the Kenwood, which is what I preferred. The Pioneer seemed to offer more for the price. Better wattage, etc. [ Thomas  Oct 20, 2016 ]

4 questions already asked

You will want to contact an Advisor by phone (1-800-324-9695) or online chat to discuss compatibility with your factory system. They will be able to pull up your vehicle and see if this will integrate. If it does not, then they will also be able to discuss other options with you. [ Krissy  Aug 10, 2018 ]  Staff
If you purchased the product from Crutchfield, feel free to contact our Tech Support team. They can walk you through the settings on the product and see if there may be a fix. Our toll-free Tech Support number is printed on your invoice, and is also available under the "My Orders" tab in the "My Account" section of our website. If you did not purchase the unit from Crutchfield, then you may want to contact the manufacturer, or try our online support center: http://crutchfield.custhelp.com/app/answers/list/kw/. [ Krissy  Nov 07, 2017 ]  Staff
Crutchfield customer service /advisors are who you want to talk to. [ dmart  Nov 03, 2017 ]
The amp is made for the speakers in your door you could power a subwoofer as long as the sub rms watts is 100 or lower so you can make sound out of the subwoofer but really you should get a separate amp that is bridgeable and made specifically for a subwoofer it will sound a million times better if you buy the pioneer it is nice for the price I had to send mine back due to overheating issues but other than that it has been great. If you do end up buying the amp make sure your speakers that you hook up too it are nothing lower than 60 watts rms just to keep from overpowering the speakers and blowing them because the amp puts out 60 watts rms. [ Scott  Aug 26, 2017 ]
If you know how to do bridging on 2 channels of an amp, you could use it for 2 speakers and 1 sub woofer (around 45 watts RMS into 8 ohm, higher into 4 ohm). FD [ Forrest L Dilley  Aug 19, 2017 ]
Not knowing how many subs or speakers you want to drive, you will want to use the 4 ohm versions or create a 4 ohm load. It is 195 watts bridged 4 ohms. Not stable in 2 ohm loads. It will depend on the music, desired volume level, and the amount of ambient background noise you have. Your question is limited in information to make a complete answer. It's a bit like asking about the weather and only being told the temperature without mention of clouds, wind, humidity, etc. that make significant differences in how it feels. In your case, 4 speakers and two subs, or 2 and 2, or 4 and 1.....? Do you need fader controls? [ Steven  Aug 19, 2017 ]
Articles