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Pioneer GM-D8604

4-channel car amplifier — 100 watts RMS x 4

35 Reviews | 17 questions - 35 answers


Our take on the Pioneer GM-D8604

Pioneer's sharp-looking GM-D8604 4-channel amplifier can send 100 watts RMS to each of your front and rear speakers, for powerful music that'll get you and your car rockin'. Highly efficient Class D technology keeps this powerful amp running as cool as it looks, and allows for a compact chassis that fits in a lot of out-of-the-way spaces. If you're building a big system in stages, you can use this versatile amp at first to drive a pair of speakers with the front two channels while bridging the rear channels together to power a subwoofer with up to 300 watts RMS. Later on, you can get Pioneer's big mono amp to drive your subs, and switch this amp over to run all four of your full-range speakers.

Cool power

Pioneer's sharp-looking GM-D8604 4-channel amplifier can send 100 watts RMS to each of your front and rear speakers, for powerful music that'll get you and your car rockin'. Highly efficient Class D technology keeps this powerful amp running as cool as it looks, and allows for a compact chassis that fits in a lot of out-of-the-way spaces. If you're building a big system in stages, you can use this versatile amp at first to drive a pair of speakers with the front two channels while bridging the rear channels together to power a subwoofer with up to 300 watts RMS. Later on, you can get Pioneer's big mono amp to drive your subs, and switch this amp over to run all four of your full-range speakers.

Connecting and tuning made simple

If your car stereo doesn't have RCA outputs, you can use the speaker-level inputs to hook this amp into your system — the amplifier switches its input mode automatically when it detects the high-level signal. And the built-in high- and low-pass filters let you adjust the sound for your car's interior, whether you're driving speakers or subs.

I'm powering 2 pairs of kicker 6.5" components (ks series)

Christopher, Glen Burnie, MD

What's in the Box:

  • 4-Channel amplifier
  • Two 30 amp ATO fuses (installed)
  • Two 8" Speaker-level input adapters
  • 3mm Allen wrench
  • Four 5/8" Self-tapping screws
  • Owner's manual (English/ French/ Spanish)
  • Warranty information

Product Highlights:

  • 4-channel car amplifier
  • 100 watts RMS x 4 at 4 ohms (150 watts RMS x 4 at 2 ohms)
  • 125 watts RMS x 4 at 1 ohm
  • 300 watts RMS x 2 bridged at 4 ohms (250 watts RMS x 2 bridged at 2 ohms)
  • CEA-2006 compliant
  • full-range Class D amp technology
  • variable high- and low-pass filters (40-500 Hz, 12 dB per octave)
  • preamp inputs and outputs
  • speaker-level inputs via supplied RCA-type adapters
  • fuse rating: 30A x 2
  • 4-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 11"W x 2-3/8"H x 7-7/8"D
  • warranty: 1 year
  • Our 60-day money-back guarantee

Pioneer GM-D8604 Reviews

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(35 Reviews)
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Hands-on research

Product Research



CEA 2006 Compliant: The Pioneer GM-D8604 4-channel amplifier power ratings are measured according to the Consumer Electronics Association's CEA-2006 standards. These standards allow you to accurately compare the rated power output of all CEA-2006 compliant amplifiers, even from different brands. Manufacturers who adhere to the standards can display the CEA-2006 logo on their products and packaging. CEA-2006 Specifications:

  • Power Output:
    • 100 watts x 4 at 4-ohms with <1% THD+N
    • 150 watts x 4 at 2-ohms with <1% THD+N
    • 300 watts x 2 at 4-ohms with <1% THD+N (bridged)
  • Signal to Noise Ratio: 75 dBA

Class-FD Amp: A Class-D amplifier offers higher power in a smaller chassis than conventional Class-AB amp designs. Pioneer's exclusive Class-FD design not only delivers full-range Class-D amplification, but is more efficient than other designs. The result is clear full-range sound in a small amplifier. The ultra-compact design provides many installation options.

Channel Layout: The GM-D8604 is a 4-channel amplifier; both halves are bridgeable, so it can be wired as 4-channel, 3-channel, or 2-channel. Rather than front and rear, the two sections of the amp are labeled A and B (on both the inputs and outputs).

Auto Turn-on: When using a high voltage speaker level input, a signal sensing circuit will automatically turn the amp on and off along with the source unit.


Input Select Switch: The amplifier's input select switch allows you to choose between 4-channel and 2-channel mode. The 4-channel mode requires that two pair of RCA inputs be connected to the amplifier's A and B inputs, while the 2-channel mode only requires one pair connected to the A inputs.

Gain Control: There are independent gain controls for the A and B amplifier sections, each is continuously variable from 200 mV to 6.5 V.

Crossovers: The A and B sections also have independent crossover controls, each has:

  • Crossover Select Switch: three position switch; LPF (Low Pass Filter), Off (crossover is bypassed), HPF (High Pass Filter)
  • Frequency: continuously variable from 40 to 500 Hz


Power: The power and ground connections are set screw terminals that will accommodate up to 4-gauge wire. The included 3mm Allen wrench is used to tighten and loosen the terminals. Pioneer recommends different power and ground wire gauges based on the length of the wire:

  • 8-Gauge: up to 14' 9"
  • 6-Gauge: up to 23' 7"
  • 4-Gauge: up to 37' 5"

Remote Turn-on: The remote connection is a set screw terminal that will accommodate up to 8-gauge wire. The included 3mm Allen wrench is used to tighten and loosen the terminals.

Speaker Connections: The speaker output screw terminals will accommodate up to 8-gauge wire. The included 3mm Allen wrench is used to tighten and loosen the terminals.

Signal Input: The amplifier features two pair of stereo RCA inputs (A/B). If no line level signal is available, use the included speaker wire to RCA adapters.

RCA Output: The one pair of preamp output jacks provide a convenient way to daisy-chain an additional amplifier without running another set of RCA cables from the front of the vehicle to the amplifier location. The output is identical to the A channel input and is not affected by the internal crossover.

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.

Staff Reviews

Product reviews from the Crutchfield Labs

Pioneer's versatile 2013 car amplifiers help you get needed power to your speakers. They're compact, powerful, and even 1-ohm stable so it's easy to match subs.

What are the Labs?
Q & A

Customer Q&A

Crutchfield asked  
Why did you buy this?

It was inexpensive and will get me through until I can afford the JBL GTR-104. [ Clyde  Jun 14, 2017 ]
needed the powwwwer [ Ethan  Jun 06, 2017 ]
Good Power. It looks like it will fit where I want to put it: Under the back seat. Low THD and high Signal to Noise [ Mark  Apr 27, 2017 ]
I chose this one because it was less expensive and it was able to run 100 watts rms on each channel. [ Alixandria  Apr 22, 2017 ]
amps and I have heard from friends that Pioneer puts out good product. [ CARL R.  Apr 07, 2017 ]
Product quality as well as price [ Kevin  Apr 05, 2017 ]
For a slight step up in price (~$30) I could double my output RMS wattage, adjustable high and low pass wattage, aftermarket stereo inputs (RCA) and simple outputs to speakers. [ Scott  Apr 04, 2017 ]
Price and Specs [ Kelley  Mar 16, 2017 ]
To be obnoxiously loud ð??? [ Benjamine  Mar 14, 2017 ]
want to see if its cleaner sound than the alpine mrv-m500 I have the bassline 10'' and you can tell when it starts thd and drops off [ TOM J  Feb 17, 2017 ]
Great value for the price! [ TAINY  Feb 16, 2017 ]
Garret recommended it to me . [ MARCO A  Jan 22, 2017 ]
Andy recommended. Needed 4 channel amp with pre-out to another amp for sub. [ Greg  Jan 14, 2017 ]
I chose this amp because of the price and because it matches the max RMS of the Polk DB+ Components and 2-ways that I am purchasing for my front and back speakers, respectively. [ Christopher  Dec 24, 2016 ]
Best bang for your buck [ Mike  Nov 30, 2016 ]
Jasan suggested [ Nick  Nov 29, 2016 ]
Has great reviews [ Travis  Nov 28, 2016 ]
It will power my 4 Polk DB652 speakers in my 2016 civic lx. [ Zach  Nov 19, 2016 ]
Flexibility of use. I plan to use it to power 4 full range speakers. Possibly later add a Sub Woofer. The specifications seemed strong relative to its price. The physical size of the unit will allow more than one option for the mounting location for my application. [ David  Oct 16, 2016 ]
Watts per channel. [ Anthony P.  Sep 11, 2016 ]
Called tech support to ask about the amp I was going to use. Found its not as powerful as I thought it would be. Asked to be switched over to sales. Great Service!!!! [ Jed  Sep 08, 2016 ]
compact and powerful [ Travis  Aug 27, 2016 ]
Because of the brand name prestige, and the item specifications, and price. [ felix  Aug 21, 2016 ]
The Pioneer GM-D8604 best balances the amp's power and features with my cost. It's a good value overall. [ Greg  Aug 16, 2016 ]
Price and reviews [ Ken  Aug 15, 2016 ]
recommended from the sales person [ isaias  May 29, 2016 ]
I like the price and RMS per channel. [ Ed  Feb 07, 2016 ]
Excellent Amplifier for a great price. [ Larry  Dec 11, 2015 ]

17 questions already asked

It is possible to use this amp with the first 2 channels powering those speakers and then bridging the other 2 channels. This amp outputs 300 watts RMS at 4 ohms when you bridge those 2 channels together. HTH! My Bio: [ Paul  May 08, 2017 ]  Staff
I'm not aware of any tweeters that are rated to handle that much wattage RMS but, you could bridge the amp down to two channels and use them to power a left & right pair of speakers (or tweeters) that are at least 4 Ohms. 8 Ohm speakers/tweeters would get around half the rated output so up to 150 watts x 2 in this scenario. For additional assistance and personalized recommendations, feel free to contact us directly: I hope that helps [ Ryan  Apr 22, 2017 ]  Staff
You will have to use an amplifier installation kit. Buy the kit that fits the amplifier and follow the directions on the amplifier installation instructions. There is a lot of information online as well as from crutch field to help you with the installation. So simply no you cannot install it with factory wiring you must use a amplifier installation kit. [ george leland  Feb 05, 2017 ]
Stock electrical?? No, you need to run proper gauged wire from your battery to the amp. [ John  Feb 04, 2017 ]
It's built just as good in the model. I hooked it up without using separate LOC and it works perfect. [ Alex  Jan 18, 2017 ]
Joseph has you covered here Glenn. Just be sure that you're connecting a minimum 4 Ohm load to the bridged channel. You can also view the connection options in the Pioneer owner's manual. You'll find the link to the manual under the "What's in the Box?" heading on the amplifier's main webpage. I hope that helps. My Bio: [ Ryan  Sep 17, 2016 ]  Staff
The best way to bridge a 4 channel amp is to use positive on one channel and negative from one channel. [ JOSEPH  Sep 16, 2016 ]
Thanks for your question. No it does not. You can find this information on the product page Details tab under "Features". Hope that helps. [ Kenny  Jul 30, 2016 ]  Staff
The Pioneer amp is stable down to 1 Ohm per channel so it can certainly work with 3 Ohm speakers without issue. You can expect up to 125 watts RMS per channel at a true 3 Ohm impedance. Keep in mind; the added resistance of the speaker wire will present much closer to a 4 Ohm final load with the JBL speakers. I hope that helps! My Bio: [ Ryan  Apr 27, 2016 ]  Staff
As Lance Holmes mentions above, it would be a lot easier if you know what the crossover frequencies in your factory system are; otherwise it's basically guessing. You could also install new components that include their own crossovers to replace your factory component system. You can find a full listing of aftermarket component speakers we carry on our website here: I hope that helps. My Bio: [ Larry  Mar 30, 2016 ]  Staff
It would be best to find out what the crossover frequencies are, and either find a crossover that matches it or build one. [ Lance  Mar 30, 2016 ]
No it doesent and it doesent have a connection spot for one either. [ DARNELL  Jan 02, 2016 ]
Mine didn't come w one. [ Josh  Jan 01, 2016 ]
This unit does not come with the bass knob. The bass knobs use an RJ-25 telephone type connector on both ends. The amp would have to have the RJ-25 connection to be able to add the control knob. Any amp we sell that includes the control would have that type of connection. Hope that helps. [ Kenny  Jan 01, 2016 ]  Staff
I Use it in conjunction with a 1000 watt mono alpine amp with two type R alpine 12" subs in a sealed enclosure. So I don't drive the low frequency information through the pioneer amp. It works well for that. Not sure how it pushes the full frequency. Sorry I can't really honestly answer your question. [ Preston  Sep 02, 2015 ]
Yes, this will handle 100w RMS (continuously) for 4 channels. And more for speakers that have less resistance (ohm value). [ Michael  Sep 02, 2015 ]
yes it will work fine better to have too much power than not enough in most cases [ Larry  Sep 02, 2015 ]
I switched to a kicker amp, so much less feedback from the kicker amp [ LINKS  Sep 02, 2015 ]
THere is a great article which will help with this and many other questions about car amps at crutchfield articles glossary of car amp terms. Really informative. Btw I love my Pioneer amp. I use it to supply my four alpine speakers for mids and highs and a 1000 watt alpine mono amp to push my dual alpine subs. Awesome! [ Preston  Jul 01, 2015 ]
Class D amplifiers use output transistors as switches to control power distribution - the transistors rapidly switch on and off at least twice during every signal cycle. Class D amps boast higher efficiency, produce less heat, and draw less current than traditional Class AB designs. Class D amplifiers produce higher distortion than AB designs due to the high-speed switching on and off of the transistors, but this distortion occurs at frequencies above hearing, and is easily removed by a low-pass filter. You can find out more about the different classes of amps here: [ Jeff  Jun 30, 2015 ]  Staff
I forwarded your question to an Advisor and they responded with the following: You can wire 4 speakers onto the two channels of this amp as long as the speakers are 4 ohm speakers. This will drop the impedance to 2 ohms on the front two channels and output 150 watts RMS which will be split in half. As long as the subwoofer is also 4 ohm then you can run it in bridged mode on the rear two channels. This will allow you to get 300 watts RMS for the subwoofer. As long as the speakers and subwoofer are 4 ohm this will be a safe setup. If you would like to discuss further you can contact an Advisor directly by phone (1-800-324-9695) or online chat. [ Krissy  Jun 17, 2015 ]  Staff
Im not sure about that. You should be able to find something in an online manual [ Preston  Jan 26, 2015 ]
Nope, you'll need one coax cable per channel. So, 4 RCA cables for 4 speakers. Good luck! [ Matt  Jan 26, 2015 ]
Robert, One set will run all four speakers. My truck has speakers in all four doors, it's a crew cab. My installation was a bit rushed, because we where leaving for vacation the next day, and taking the truck on a long drive from California to the Grand Canyon. I was having trouble getting one set of RCAs to work properly. I really wanted to have all four speakers running. so I switched the input to 2 channel mode, and ran it that way for the trip. I wasn't able to use the fader of course, but I got sound out of all four speakers. I sorted out the wiring issue when we got back. I'm very happy with this amp. sounds great! [ Lance  Jan 23, 2015 ]
Yes you need to run 2 sets of RCA's [ Josh  Jan 23, 2015 ]
A set of rca's (2) will run channel A. It would be best to run 2 sets of rca's, so you can get channel A& B. Or if you want, you can run a set of rca's and use splitters, so you get both channels. This I what I had to do. [ lukekat  Jan 23, 2015 ]
need much more info. [ RON  Jan 22, 2015 ]
Hi Donald, This amp was on my son's wish list for his birthday. I will forward your question to him. Regards, G. Fail [ GENERAL  Jan 09, 2015 ]
Yes it would work. [ Cole  Jul 27, 2014 ]
I don't believe you would be satisfied with the output power on 2 10 inch subs. I have this amp bridged on 1 channel for a 10 inch JBL sub and using the other channel for infinity components. Sounds great but I personally feel the single sub is a bit underpowered. [ Steve  Jul 27, 2014 ]
Depends on the ohms of the speakers, how they are wired, how many watts the amps produces at certain ohms. Kinda a vague question. Need more details. [ Raymond  Jul 26, 2014 ]
Are you going bridge all 4 channels? Subs 2 or 4 ohm [ Larry  Jul 26, 2014 ]
Thanks for your question. For information on pairing amps with subs I would recommend reaching out to an Advisor by phone (1-800-324-9695) or online chat. They will be able to help determine the differences between the amp models and help you make the best choice for your system. [ Greg  Jul 26, 2014 ]  Staff
George, It is doable. You need to have at least two sets of Pre-Amp outputs on your receiver, most will have three. I would hook up the sub-woofer first from your receiver to the amp and then to the sub and check to make sure it works properly. Then hook-up the front connection from your receiver to the amp and then connect your speakers. This should work. [ John  Jul 19, 2014 ]