Win the battle for great sound in your ride. Sound Ordnance amplifiers feature tough construction, rugged looks, and a 3-year warranty, so you can enjoy the full power of your music for the long haul. Even better, you can add Sound Ordnance to your arsenal at a surprisingly affordable price.

The Sound Ordnance M-4075 4-channel amplifier deploys 75 watts RMS to each channel, giving your music plenty of firepower. You can also bridge the amp to 2-channel mode to mobilize a pair of subs with 240 watts RMS each, or send 240 watts to a sub while the front channels run your full-range speakers. An adjustable high-pass filter makes sure your full-range speakers operate within their optimum range and give you the best tone possible. If you're driving a sub, the low-pass filter and selectable bass boost allow you to control your bass barrage at will.

The M-4075 amplifier uses sophisticated power supply and output technologies to ensure clean amplification from its inputs all the way to your speakers. Special circuits protect the amp against overheating and short circuits, while a turn-on delay virtually eliminates that annoying thump when you turn your system on.

Product Highlights:

  • 4-channel car amplifier
  • 75 watts RMS x 4 at 4 ohms (120 watts RMS x 4 at 2 ohms)
  • 240 watts RMS x 2 bridged at 4 ohms (4-ohm stable bridged)
  • variable high-pass filter (80-2K Hz, 12 dB/octave)
  • variable low-pass filter (50-250 Hz, 12 dB/octave)
  • selectable bass boost (0, 6, and 12 dB at 45 Hz)
  • PWM (pulse width modulation) power supply with MOSFET output
  • preamp inputs and outputs
  • fuse rating: 30A x 2
  • 8-gauge power and ground leads recommended — wiring and hardware not included with amplifier
  • 15-3/4"W x 2-1/8"H x 9-3/4"D
  • warranty: 3 years
  • Our 60-day money-back guarantee

My system has plenty of power. Who needs an amp?

You might think you don't need an amp because you have a 400-watt system in your car, or because your new stereo puts out 50 watts a channel. But those are peak wattage ratings, which may boil down to 15 or 20 watts per channel, using the more realistic RMS rating. An amp sends your speakers the power they need to deliver your music with clarity and impact, whether you're using factory speakers or high-performance components. And low-frequency reproduction requires lots of power, so an amp is an absolute must if you're adding a sub to your system.

Sound Ordnance™ M-4075 Reviews

Average Customer Review:

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Written By J., Alabama on Sunday, July 19, 2015

Crutchfield Customer Review (What's this?)

This amp is very clear and clean on sound but goes into protect mode and get very hot after just a few minutes of play.

Pros: Sounds good

Cons: Get very hot and cuts off after a few minutes of play

Amazing value

Written By Aaron, Austin on Thursday, May 07, 2015

Crutchfield Customer Review (What's this?)

I bought this to power a 4 speaker system, and eventually add a sub. It powered the 4 speakers (all 50w rms) like nobody's business, I was able to crank them higher than comfortable. When I added the sub, I bridged the rear channels to the sub, and sent the front channels to both my front and rear interior speakers (wired in parallel, so 2ohm impedance, should be 120w total, 60w each speaker). Everything bumps amazingly with this setup! I can let the whole block know what I'm listening to if I want, and I can drive at 80mph down the highway with the windows down, and turn the system up loud enough to hear the music perfectly. I can't imagine what else anyone could want from a system. But beware! This thing overheats like crazy. Even when it was just powering my 4 speakers it got pretty hot to the touch, and now with the sub it will go into protection mode if I run it too long at a loud volume (not crazy loud, just loud). I realize I'm running two channels at 2 ohms, and the other two are bridged powering a 300w sub, but it kinda sucks that I can't run my whole system from one amp. I bought a power inverter and am running a small desk fan blowing over the amp, and that helps, but still doesn't fix the problem. It seems weird to me that there are no heat sinks or vents on something this heat-productive.

Sound Ordnance™ M-4075

Written By dennis, Archer City Tx on Monday, April 27, 2015

Crutchfield Customer Review (What's this?)

I bought this amp to power four kicker k series speakers in the front and rear doors of my truck, I only have to turn the gain up to about 60%. It has more than enough power! Works great, sounds great, great price. I had to install it under the rear seat because of the size.

Pros: lots of power, low price

Cons: A little big

Sound Ordnance™ M-4075

Written By Michael, Kentucky on Monday, April 20, 2015

Crutchfield Customer Review (What's this?)

almost immposible to adjust

Crutchfield response on Monday, April 20, 2015 We forwarded this review to our Technical Support team for follow-up. Lifetime tech support comes with every Crutchfield purchase.

Excellent sound - even better price

Written By Anthony C., Raleigh, NC on Sunday, April 19, 2015

Crutchfield Customer Review (What's this?)

This amp sounds amazing. I had a set of Polk dB 6x9's in my truck, hooked up to the factory radio. They never sounded great, better than stock speakers, but they didn't really shine until I installed this amp. Clarity is amazing, and these will get louder than I even want them to. Provides plenty of power, at a great price.

Pros: Clear, distortion free Great price No need to pay more

Cons: Haven't found any yet

Amazing performance and value

Written By MJ, Texas on Wednesday, April 08, 2015

Crutchfield Customer Review (What's this?)

When I first ordered this amp I could not wait for it to be shipped to me so I went to a local store and bought the Kicker 12CX300.4 4-channel amp and the Kicker 40TCWS104 subwoofer to play with until my shipment arrived, so I have a direct comparison. The Kicker amp has a much smaller footprint, easy to see from the dimensions, however, it costs nearly double the SO and my particular kicker was very noisy. When setting the gains the head-unit couldn't go past 26 (out of 40) with a zero gain on this unit. The same cables/setup/head-unit could go all the way to 36 (out of 40) with this SO amp at zero gain. Their is virtually no noise when low volumes are used and there is Zero amp turn on noise. The Kicker was literally very noisy at low volume, I actually went out and rewired my car with high quality cables twice before my SO amp arrived, the new cables did nothing for the kicker, noise still there. Once I insalled the SO, noise gone. Not only that, it is very powerful. I first set all my gains proper with O-Scope and checked with multimeter, outperforms rated output. I have this configured in a 2 front and bridged sub setup, I have to turn down the front gains a little bit just so I can get the bass to a reasonable level in comparison otherwise the crystal clear highs would shred my ears before I could turn up my system loud enough to get some thump. Excellent product, clean clean sound and powerful, will def be getting SO amps for all my family members from now.

Pros: Classy finish, great power and low distortion.

Cons: Large but I knew the measurements going into it.

Sound OrdnanceT M-4075

Written By Kanaka, Washington on Tuesday, March 31, 2015

Crutchfield Customer Review (What's this?)

Put this in my '91 Jeep Wrangler, under the drivers seat. Had to build a mount since the floors are not flat. Plenty of power to drive six speakers. Watch out when installing, the screw holes for mounting are plastic and I've heard of people having them crack on them. Come on Sound Ordnance, instead of including goofy "Dog Tags," fix this. The amp itself is a little on the large size, so if space is tight be sure to measure before ordering. For the money, I'm happy. If it survives the summer in the Jeep,I may buy another.

Pros: easy to use adjustable filters good warranty price

Cons: plastic mounts large size

Sound Ordnance™ M-4075

Written By David, South Charleston WV 25309 on Tuesday, March 24, 2015

Crutchfield Customer Review (What's this?)

This is a great amp in performance and price

Pros: It is easy to set up and operate

Great Budget Amp

Written By TRM, Durango, CO on Monday, February 23, 2015

Crutchfield Customer Review (What's this?)

I have it running my 2 front door speakers- Infinity Kappa 5.25 Components and a JBL Sub under the rear passenger seat. 2014 Ram 1500 Crew. The sound is great, really picked up the Infinity's and there is no problem powering the Sub. I also have 2 Infinity 6X9 in the rear doors, powered by the factory head unit. I keep the gain minimal to not drown those out. Crystal clear sound and it starts up dead quiet. The Amp is missing some features found on higher price amps but it appears they spent the money on quality power. 5 stars based on the price/performance curve.

Pros: Price to power.

Cons: missing some high end features


Written By Brad, New Jersey on Monday, February 09, 2015

Crutchfield Customer Review (What's this?)

i was looking for an amp to power my setup and didnt want to break the bank. i was looking at all the high up brands. alpine, kenwood, kicker, etc. but this was exactly the same. but what sold me is the 3 year warranty.

Pros: everything

Cons: havent found any yet

Sound Ordnance™ M-4075

Written By Anonymous, Norfolk on Saturday, January 31, 2015

Crutchfield Customer Review (What's this?)

Good amp

Working Great!!

Written By kinsar, Florida on Wednesday, January 28, 2015

Crutchfield Customer Review (What's this?)

Installed this to run the door speakers and tweeters in my crew cab Titan. Working great. Barely have the gain turned up and it puts out clean, clear, loud music on all 8 speakers. Barely gets warm and has more power than I could put through these speakers even if I wanted to.

Pros: Sounds great, tons of power, runs cool, price is dirt cheap. If you factor in the free install kit they give with it "they are practically giving the unit away" This isn't a competition amp I'm sure, but it puts out more power cleanly than I dare to inflict on my ears.

Cons: None.

Great Amp for the price

Written By Boom Boom, California on Saturday, November 01, 2014

Crutchfield Customer Review (What's this?)

Bought this amp to replace an old JBL amp to power my four 2-way speakers. I was a little skeptical at first but knowing that this was a Crutchfield brand gave me enough confidence. The design is a little strange because the vents are on the backside of the amp and the cover isn't removable which leaves little room for the screwdriver at a strange angle. With that said, the power is awesome! Nice and clean sound with plenty of adjustment features. I haven't tested it on a long road trip yet but from the 45 minute commute to work with the volume cranked, it hasn't been very hot at all. Would definitely recommend buying.

Pros: Power, clean sound

Cons: Awkward design, little bulky, hard to mount


Written By Jon, Cali. on Wednesday, October 22, 2014

Crutchfield Customer Review (What's this?)

Excellent, powerful, inexpensive, impressed.

Pros: Cost, power versus price. I had full Alpine systems in the past, now still have Alpine head unit and speakers, but the S/O amp is just as impressive.

Cons: None.

Getting what you paid for

Written By Ben, Rhode Island on Sunday, October 12, 2014

Crutchfield Customer Review (What's this?)

First off, credibility. I install sound systems as a side hobby for everyone and anyone. I have been building and installing products for 5 years now and know car audio quite well. With that being said, i hope you take my review to heart, as I have no altereior motives or intentions. I always want people to have the best sounding audio for the budget they have, so here is my review of this amplifier.

I ended up giving this amplifier a very generous 3 starts. I have had 2 of these (first one broke), and used for 2 years. The first one of these had bad dials on them, and eventually i could not adjust any levels on the amplifier, and the output RCA never worked.

This amplifier will definitely power your speakers, no doubt about that. But quality is something left to be said. I have many issues with feedback through my speakers that have all be diagnosed to be the amplifier. The inputs are alright. They can be slightly tough to screw in if you have the side mounts attached, but not a huge issue. Actually mounting the amp is a challenge in itself. I screwed it into the box and the screws tore up the flimsy plastic slot that the screws must go into. I also had the amp fall on me before, and snapped the bottom two screw holes right off the mount. Like i said, very flimsy, cheap plastic on the side mounts. I had to use 3" screws with washers just to keep it up. you also cannot tune this amplifier very well. Never could use anything other than HPF. Invest in another amp IMO

sound ordnance m-4075

Written By phil, winter haven fl. on Sunday, September 14, 2014

Crutchfield Customer Review (What's this?)

I. Love this amp I would tell anyone to get it i have not had any problems with it . I had a sound shop to put it on so it works great they set the gain so I am really pleased.

Pros: Great amp made my 8 inch kicker sub rock

protection mode

Written By Griffin, West Palm Beach, fl on Thursday, August 28, 2014

Its a great amp for the first 3 months then it will go into protection mode or over heat, it only runs a 12 inch sub and should be fine for hours but after about 10-12 minutes of play at about 20% power the sub will go into protection mode and will not come out for about 20-30 minutes or you have to shut off the car and restart it. I have it in a open area in my car and it I even have a ac vent blowing straight on it and it will still do it. I shall be returning said unit

Pros: Works great for 3 months

Cons: Goes into protection mode for no reason

1 Year later with the M-4075

Written By Anonymous, Cincinnati on Sunday, August 17, 2014

Crutchfield Customer Review (What's this?)

Got this amp almost exactly a year ago. I have it installed underneath the front passenger seat of my 06 Toyota Matrix.This amp is powering two Infinity Reference 6032cf in the front and one 10" Kicker in the back(bridged rear). Not only does this push some great bass, but my infinities are incredible sounding to. I just got back from a trip to Cleveland and this trip prompted me to write this review. The trip was over 3 hours long and the entire time it was was pushing loud enough music to roll with the windows down on the highway. It got hot, but definitely not too hot and it only had less than a centimeter of space between the bottom of the amp and the carpet(Its probably shifted since I installed it so there could be even less space). I was waiting for it to over heat and cut off, but it never did. The sound is great on all the highs, mids, and lows. Very very happy with this purchase.

Pros: Can go for hours. Really great sound. Easy to set up. The price is awesome for something that has lasted me a year.

Cons: I would say it is too big, but that wouldn't be true since it fits perfectly underneath my 06 Matrix passenger seat.

M-4075 review

Written By JerrodA, Glasgow, KY on Sunday, July 27, 2014

Crutchfield Customer Review (What's this?)

Amp gave good quality to my Kenwood component speakers and JL Audio 10W1X2. The sub sounds awesome. I didn't know if 240 RMS from the amp would drive the 300 watt RMS sub that well, but it does. I couldn't believe the bass I was getting from one 10". The amp is big, but it works really well under the passenger seat of my 09 silverado reg cab. I can reach the gains from the front of the seat and connect the speakers from the back so the length is actually an advantage for this vehicle. I'm so glad I purchased my amp and Kenwood DPX500BT head unit from Crutchfield. Yea, you might be able to search around and get it cheaper, but if anything goes wrong Crutchfield will fix it, no questions asked. You can't get that kind of service from other online sellers. For the money this amp is awesome and with a 3 year warranty, it's hard too beat. I would recommend to anyone.

Pros: Good sound quality Great power output for the money

Cons: none

awesome sound

Written By Ian, St Clairsvle, OH on Monday, June 09, 2014

Crutchfield Customer Review (What's this?)

This amplifier is a must for an upgrade to your sound system. It has gain and frequency setting Which you can adjust feedback out of the system. Only this I would recommend is having stronger holes on the edges so you can bolt it down more. But it is still bolted down and sounds a lot better with my keenwood speakers!

Pros: Sounds great, high and low frequency with gain and frequency adjustments

Cons: The bolt holes are not solid metal


Written By Dan, Nebraska on Thursday, April 17, 2014

Crutchfield Customer Review (What's this?)

I do love this amp, right now I have it coupled to two CDT ES 6x9's and it sounds great. The only problem I've had with it is when I bridge it to give each speaker max power, only the speaker bridged on the rear channel can use the LPF. The front channel only has full or HPF as an option. If I want to use both speakers with the LPF, they only get 75W RMS. The amp itself is a little big, but it's dimensions actually fit perfectly in the trunk where the tire repair kit goes.

Pros: Nice clean sound, great value

Cons: A little big, and a little flashy with all the chrome, LPF only works on one channel if bridged

great amp

Written By joe, va. on Monday, March 24, 2014

Crutchfield Customer Review (What's this?)

this thing is amazing,i never expected this much power out of something that cost so little.did plenty of research on this,amazing numbers was what sold me.freq. response and distortion ratio are better on paper than most high end amps i compaired it to.installed over the weekend and the numbers dont lie.i have thrown everything at this to find distortion,there is none to be had.this thing is just plain awesome.another concern was i read it gets hot,i have not had this problem.although i did make some plates to mount about a half inch off the floor as to let air move around and under stays nice and cool.would highly recomend this.

Great amp

Written By Anonymous, Nebraska on Saturday, February 22, 2014

Crutchfield Customer Review (What's this?)

Works great for my JL audio 6"s No issues since installed over a year ago.

Sound Ordnance™ M-4075

Written By Kyle R, Saint johns florida on Monday, January 13, 2014

Crutchfield Customer Review (What's this?)

This amp is purely amazing I have the m1500 amp running my sub then this m4075 amp on my mids and high and man does this thing get the job done all the range I need or wanted is in side this amp. It is a little big in size but no big deal for the way this amp brought my system to life there's no room to complain love the sound ordnance brand they always amaze me!!

Pros: Just completely awesome!

Cons: Little big of an amp but with this kinda sound it's worth it!!

s/o m-4075

Written By fred m, on Thursday, November 14, 2013

Crutchfield Customer Review (What's this?)

great product for the price

Pros: price

Cons: size of amp and screws to attach wires


Written By john mc, ogdensburg ny on Tuesday, November 12, 2013

Crutchfield Customer Review (What's this?)

this is an awsome amp for 6x9s and very pleased with this product

Pros: everything

Cons: none

It's ok

Written By CraigM, Hartford, MI on Sunday, November 10, 2013

Crutchfield Customer Review (What's this?)

I was replacing an old Profile amp and this was the closest match I could find. I'm pretty satisfied with this amp but not too thrilled with the chrome ends. They overhang the lugs for all the connections and make it far more difficult to install than it should have been. Other than that, I'm pretty satisfied.

Amp does the job

Written By Mitch, fort knox, ky on Sunday, October 27, 2013

Crutchfield Customer Review (What's this?)

I think i like these amps alot. The size is a bit big. Kinda classic but its clean and performs very well

Pros: Seems to work perfect. price

Cons: Size of amp and the mounting screw area.

Great buy

Written By Chris from McKinney, McKinney, TX on Sunday, September 29, 2013

Crutchfield Customer Review (What's this?)

Can't beat a Sound Ordinance amp for the price. Definately performs. Read some reviews about noise problems. I took good care to give it a good ground in my F350, and I have no noise at all. Goot clean power. Not really sure what spending $300 more for an amp would buy you? I am running it on front and back JBL speakers. No sub. These speakers are power hungry and the amp does get hot. Not sure how it would perform w a sub.

Pros: Price, good instructions, good build

Cons: For some cars, amp may be a little large, but fits under F350 rear seat without problems.

Not For Sub Use

Written By Jason, Houston,TX on Thursday, September 05, 2013

Crutchfield Customer Review (What's this?)

I took a chance on this amp because I have been pleased with their products in the past. This amp works great if you use it as a component amp ONLY. Sound is excellent for mids and highs. Plenty of power. However, this amp performs poorly pushing a real sub. The sound is excellent and has plenty of power, the problem is it cannot get the heat out and will overheat and go into protect mode very quickly even at moderate listing levels. This sucker runs HOT pushing a sub. Don't even try it. Use for components only.

Pros: Great as a component amp.


Sound Ordinance M-4075 Amp

Written By Doug, Santa Cruz., CA on Thursday, August 08, 2013

Crutchfield Customer Review (What's this?)

Works well. Hasn't failed yet. Good product for the price.

Pros: Good power for the price.

Cons: A little heavy.

Not Bad, Not Good

Written By noldevin, Saddle River, NJ on Friday, August 02, 2013

Crutchfield Customer Review (What's this?)

Decent amp for a pretty low price. Using it to drive my polk component 5.25s in front and polk 2-way 5x7s in back. 100w in front 60w in back, all 4ohm. This amp generates a lot of alternator and electrical noise if I turn it up past 25%, even with grounded RCAs. The unit holds up fine in most weather, but on hot summer days it sometimes overheats and shuts off, even below 25% gain.

Pros: Inexpensive and powerful.

Cons: Overheats on hot days, generates noise, rather large in size.

Sound Ordnance™ M-4075

Written By Anonymous, Orange County, Ca on Saturday, July 06, 2013

Crutchfield Customer Review (What's this?)

Bought this amp because of the low price, I like it but it would not fit where I would have liked due to it's size, and it is a little noisy. Its a good budget amp

Pros: price

Cons: noise and size

Beginners Amp

Written By EricR, Annapolis, MD on Wednesday, June 26, 2013

Crutchfield Customer Review (What's this?)

Bought this amp because of the low price to put in a cheap used SUV I recently purchased. I like it but it would not fit where I would have liked due to it's size, and it was a little noisy when not playing music. I installed RCA line-in filters on the patch in cables which definitely helped. At this point, it sounds great, but I can't help but think I should have spent a little bit more on a nicer amp which would have been smaller and not needed the filters.

Pros: Low cost, powerful amplifier.

Cons: Large size, needed line-in filters to clean up sound

Awesome Amp

Written By Mike, Wisconsin on Saturday, June 22, 2013

Crutchfield Customer Review (What's this?)

Awesome amp, good instruction, beautiful finish.

Pros: Easy to install, looks great, works great

Cons: None

plenty of power to spare

Written By jim, Fresno, TX on Monday, June 10, 2013

Crutchfield Customer Review (What's this?)

seems to work very well. has power to spare. easy to install and hook up.

Great product

Written By Mike, Live Oak, Texas on Thursday, June 06, 2013

Crutchfield Customer Review (What's this?)

The amp was recommended by a friend and it couldn't have been better for my application. I replaced factory speakers and added this amp. Car sounds great w/o the overwhelming boom that subs add. Just looking for better sound, not rattling everything I own. Still messing around with fine tuning the amp, but was happy even before adjustments. Install was easier than expected even for a novice like me. Amp looks good, but is rather large, so keep that in mind. Imo it's a small price to pay for what it gives you.

Pros: Quality look/sound Versatility Ease of use

Cons: Size, if anything

plenty of clean power!

Written By Tom P., Folsom Ca on Tuesday, June 04, 2013

Crutchfield Customer Review (What's this?)

Lots of clean power for a great price. At less than half the gain this amp cranked my G35 and really woke my Bose speakers. I switched to a 12" alpine sub and some kicker 6 3/4 speakers in the front doors (all from Crutchfield) and WOW! This 4 channel amp has more than enough power for this system using its 2x 75watts for soundstage front speakesr and 270 watts bridged for a mono sub in the trunk. It is insane loud and hum or distortion. The amp also runs nice and cool even when I push it. Performance is a 5+ but because of the case I have to give it a 4. The box design is a bit odd as others have posted. Its big; the vents r on the bottom so you have to elevate or mount upside down; the ends have an overhang ledge which interferes with the wire connections esp. in tight hookup locations; and wires connects and controls are intermixed on opposite ends making it a bit challenging to hookup and adjust. But I consider these minor given the price and performance

Pros: Lots of clean, cool, power. Price. Easy install if you have the space. looks cool

Cons: Minor but, big and somewhat odd case design (vents and end plate overhang)

Great amp

Written By AH, Fort Worth, Texas on Friday, May 17, 2013

Crutchfield Customer Review (What's this?)

Easy to install with great crossover features. I would definitely buy another.

Sound ordnance

Written By Ramon P, Egg harbor twp nj on Friday, May 10, 2013

Crutchfield Customer Review (What's this?)

The sound is awesome, easy to install The disign is elegance


Written By Damon, Gilford, nh on Wednesday, April 24, 2013

The amp works great!! I was using a Sony xplod amp for my subs and I thought that was good until I put this amp in. It definitely puts off a lot of power and it still sounds clear and crisp. I love the amp I would definitely buy again!

Pros: Sounds great, not to big, looks good

Crisp, clean power

Written By Kevin Harris, Livingston,La on Wednesday, March 27, 2013

Crutchfield Customer Review (What's this?)

Bought this amp to power 4 Polk Audio DB651's in my wife's Yukon. Clean, clear power for the mids and highs.

Great Amp for the Money

Written By RyanJ, Albuquerque, NM on Saturday, March 16, 2013

Crutchfield Customer Review (What's this?)

This is my first mobile audio amp. I picked it for the power, price, and warranty. The amp provides plenty of power to my front components and a 10" sub. This amp has plenty of features for the beginner car audio enthusiast. The body of the amp itself is stiff but the cover feels flimsy. The screw holes for mounting the amp weren't aligned very well and I couldn't get a drill bit into one of the holes. The amp is indeed huge but still fit perfectly behind rear seats of my double cab Tacoma. All in all, a great amp for the money.

Pros: Price, power, adjustablility

Cons: Size, fit and finish

excellent but some design changes are needed

Written By chris, Virginia Beach, VA on Sunday, March 10, 2013

its a good up and sounds excellent but some slight changes are needed. i think its weird to have the vents to the amp on the bottom for cooling. if it is mounted to the floor it wont vent at all. it has to be elevated for it to vent properly. would be easily fixed if the vents were on the top or had a built in fan. a problem that the designers sound not of missed. the vents sound always be on the top. anyways still a solid. would by again if design changes are made.

Pros: quality amp for price. exllecent sound

Cons: needs to be redesigned

great product!

Written By josh c, Plymouth, in on Saturday, March 02, 2013

Crutchfield Customer Review (What's this?)

Good amp over all

Pros: Plenty of power. Great quality. Very pleased. I would highly recommend to anyone unless space is a concern or your going for comp.

Cons: Power and ground terminals dont support very large wires. And the angle of the terminals could be a hindrance. hex key screws would be better i picked up some from the hardware store.

great amp for the price

Written By jeff, texas on Friday, December 07, 2012

Crutchfield Customer Review (What's this?)

this amp is as good as any CEA compliant amp that i have ever owned. its pretty big, so check the specs. the plastic end caps are pretty heavy duty but don't over tighten when you mount them. some reviews complained about them being plastic but metal end caps would conduct electricity.(bad). i noticed a slight hiss between songs, but not bad. also a little engine noise, but not bad either. stays cool too.

Pros: value warranty quality customer support tons of power


Sounds great

Written By Rodney, Indiana on Wednesday, November 28, 2012

Crutchfield Customer Review (What's this?)

This amp has good clear sound.and you can not do any better for the price. On the down side is the size, It is a little large but if you have the room your doing great.

Pros: Great sound for the money

Cons: Amp is large


Written By ROBERT B, EASTPOINTE,MI on Thursday, October 04, 2012

Crutchfield Customer Review (What's this?)



Cons: NONE

Sound Ordnance

Written By Alex S., Michigan on Thursday, October 04, 2012

Crutchfield Customer Review (What's this?)

Fantastic amp here! It is a little on the big side but thats fine for me. Using it to drive 2 kicker 6x9's and a 12 inch sub. So far it has done a great job and never had a thermal shutdown, and i am maxing this thing out!

Pros: Looks great! Works as expected

Cons: Little big (not really a problem for me but for some it might)


Written By J, North carolina on Saturday, September 15, 2012

Crutchfield Customer Review (What's this?)

Great amp. Excellent clean sound and doesn't distort at all. Also doesn't get very hot and looks pretty neato.

Pros: Sound quality, stays cool, sharp looking, good power, filters are handy, easy as pie installation

Cons: Big. But that probably contributes to it staying cool without fans

Awesome Amp!

Written By ed, Janesville, WI on Wednesday, July 18, 2012

Crutchfield Customer Review (What's this?)

I used this amp as a replacement for my tried and trusted Rockford Fosgate 600a4 that I've had for over 10 years and has served me well. Both amps match out to same specs, 75x4 rms. But WOW, what a difference! I was considering replacing my polk audio 6x9s and my jl 5 1/4. This amp breathed new life into the speakers. I did'nt know amps could "wear out" without failure but this amp proves it to me. I knew the fosgate was at the end of its life cause it would overheat and go into thermal shut down. but I had no idea how much a fresh amp would help the system. My only regret is I spent a lot more money on my sub amp and should have bought a Sound Ordnance.

Pros: great sound. Easy layout of crossovers.

Cons: watch the ground and power. On the bottom of the ground it actually says "Power input" I hooked my ground up to that terminal and the ground up to the power and blew the fuses. It actually says ground and positive above the terminals but you must look at it strait on, hard to do when mounting on sub box already in trunk. not a fault of the amp, just be careful.

Good amp

Written By Anonymous, Oahu, HI on Friday, July 13, 2012

Crutchfield Customer Review (What's this?)

Good amp... Would've got 5 stars if not for the size of the darn thing!

Pros: Easy install Great highs,mids and bass

Cons: Large size(did not fit under my 08 Tacoma access cab front seats)


Written By Maurice, south georgia on Wednesday, June 27, 2012

Crutchfield Customer Review (What's this?)

This amp is awesome.Its not gonna win any compatitions but for an entry level amp, its a winner!!!!

Pros: great sound

Cons: a little large in size

Great Power- Small Price

Written By Black, Hartford, CT on Sunday, June 17, 2012

Crutchfield Customer Review (What's this?)

I purchased this amp to replace my aging (and fried) Alpine v-12 amplifier. I was in the market for something under 200.00 and with more power than the alpine's 45 W rms. My car audio needs have changed and I didn't want to pony up 400 bucks for a new amp.

I run the amp in the 3 channel mode, Rear bridged to 240 W rms to run a single sub, fronts powering MB quart 6.5" separates.

I installed it using the existing wiring from the Alpine. I had pretty low expectations to be honest, i haven't purchased an entry-level amplifier in 10 years, and was expecting to be dissapointed.

The amp performs Very well- the extra power really woke up the Separates and the Sub-woofer. EQ's were easy to adjust using a 100hz test tone, and gains were set about midway. At higher volumes the amplifier really pushes the speakers hard with no distortion.

One problem I am chasing- Noise. It was not present with the alpine, but it is definitely there with the Sound Ordinance. There is a hiss with no signal, and now- engine whine. Also, there is a soft turn on thump that was not present with the higher priced amplifier.

I'll chase the noise, probably re-do some grounds, but the noise is what kept this from a 5 star review- especially when there was no noise present with the old amplifier.

Pros: Great price, surprising power for the price! , good connections, easy to use.

Cons: Soft Hiss when no signal present, Engine noise present when old amp had none, Size (it's big)

Glad I got it!

Written By Bklynyc, DC on Saturday, June 16, 2012

Crutchfield Customer Review (What's this?)

This is a great amp. The sound is crystal clear and you can adjust it to the exact power level you need according to what sound you're looking for. The only small issue I have is its HUGE and takes up quite a bit of space (very long, that's why I gave it 4 stars instead of 5). If you want some eye candy with great sound in your trunk then you'll probably love it, if you want the same power with something that's not as big then you might be slightly (not totally), disappointed. Overall I'll take it.

As for the Crutchfield Team, this a company that runs like none I've ever seen. They repeatedly contact you after every sale to thank you, make sure your satisfied and to let you know they want you to contact them with any questions about ANYTHING! Who does this nowadays? Some businesses may do one or maybe two of those things but not all of them. I'll continue to purchase my electronics from Crutchfield fo a while to come.

Pros: Great for the price. Clear sounding and powerful. Easy to work.

Cons: Very long therefore taking up a lot of space.


Written By Mrbflyin, Rancho Cucamonga, CA on Monday, June 11, 2012

Crutchfield Customer Review (What's this?)

i got this today and would recommend it to anyone looking for a new amplifier. i never heard of S.O before but now that i have given it a try i am very impressed. now my favorite brand for audio. good work

Pros: Nice price, great quality, looks nice, fits well, powerful, not very hot after an hour of use

Cons: i have no cons


Written By KevS, Denver, CO on Wednesday, May 02, 2012

Crutchfield Customer Review (What's this?)

I am very impressed with this amplifier. It is producing power just as described and rated. The look of it is very nice. It doesn't seem to got hot after multiple hours of hard use. I am using this amp to push Kenwood 6x9 rears and 6" component fronts. They are rated at 300W max and 75W RMS. This amplifier is pushing them hard with crisp clear sound. I am very impressed with all of the features for the price.

Pros: Good price. Many options (i.e. RCA output, separate filters for front and rear speakers). Good power output

Cons: Difficult to see the power light (handy when installing and tuning). Screw downs on the speaker wire and power wires are angled, this isn't too much of an issue except for the power line. It puts your screwdriver right at the grounded metal case.

Very Impressed

Written By Dave, Oklahoma on Sunday, April 15, 2012

Crutchfield Customer Review (What's this?)

Amp works great. Nice Clean Sound!!

Pros: Clean Sound, Good Price,

Cons: none so far

Perfect for iPod "stealth" system

Written By The Image Doctor, Big D on Wednesday, March 14, 2012

Crutchfield Customer Review (What's this?)

I looked a LONG time for amps designed specifically to plug an iPod into and nothing else. Unfortunately it seems those are all discontinued. So after chatting with Crutchfield reps several times, I finally settled on the Sound OrdnanceT M-4075 for the RCA INPUTS and the VARIABLE GAIN controls.

Using a 12' mini-jack-to-RCA stereo cable, and two RCA splitters, I'm running my iPod directly into this amp. The REAR channel is running bridged into a Sound Ordnance B-12 Single 12" Vented Box in my trunk. The FRONT channels are running stereo into 6x9s (rear deck) and 5.25's (front kick panels) with the same L/R signal powering the front/rear speakers respectively. I have no front/rear fader control, but that's no big deal due to the way I have my speakers installed.

This amp has all the adjustable controls I needed (gain, crossover, bass boost, etc.) and only took me a few minutes to dial in exactly what I wanted.

My sub hits hard, the other speakers fill the cabin with sound, the system goes a LOT louder than I can stand (must mean I'm too old), and the amp barely even gets warm. What more can I say?

Great amp for the money, though I did get mine on sale here for $110 or something like that.

Pros: power, clean sound, cool running, variable gain, iPod connect via RCA cable, lots of adjustable settings

Cons: none

Great Amp

Written By JasonB, Shreveport, LA on Wednesday, February 29, 2012

Crutchfield Customer Review (What's this?)

Great amp! I using the front channels to push two Kenwood 6x9s and the rear channel to push a single 10" Boss Audio Slim Sub at 240 watts bridged and this amp is doing great and sounding awesome. The only ding against this amp is it is very large, but it's a small complaint on my part.

Pros: Great options, bridgeable. Easy to install, great sound.

Cons: A little large.

Good for the money!

Written By Frank H., East Greenbush, NY on Wednesday, February 15, 2012

Crutchfield Customer Review (What's this?)

Good amp for the money. Plenty of power, runs cool, stays clean at higher volumes. The only downside for me is the placement of the power and speaker terminals. They are angled slightly downward and this can make wiring a bit annoying.

My first car amp install

Written By gunplt, Raleigh, NC on Wednesday, February 08, 2012

Crutchfield Customer Review (What's this?)

This was my first amp install in a car, even though I have installed numerous car & home stereo systems over the years. I used a small strip of wood (5/16x3/4x11) to give the amp a little more standoff from the mounting surface for better cooling (based on other reviewer's comments on cooling issues). Given the importance of keeping the power wire away from the speaker wires to reduce the possibility of noise induction it would have been better to have placed the speaker output connections on the opposite side of the amp from the power input. This made for some awkward/unattractive routing choices for the wiring. Routing the 'amp to speaker' wires for the door speakers in my Honda del Sol was a total nightmare (nothing to do with this specific amp, just an observation).

Pros: Price, Power, Look

Cons: Mounting process/hardware, connector layout

Great Amp

Written By Rockin' Camry, Mid-Missouri on Saturday, February 04, 2012

Crutchfield Customer Review (What's this?)

Excellent amp, quite LARGE (just fits under the passenger seat in my 1999 Camry) - I have it running Focal Access 165 A1 components (6.5") in my doors/sail panels on the front channels and rear (sub) runs JBL 6x9 in the rear deck wired parallel to 10" POLK subs in a sealed enclosure into the trunk for 140 watts into 2 ohms - love it!! ;)

great amp

Written By brian m., fall river ma. on Friday, February 03, 2012

Crutchfield Customer Review (What's this?)

ive only had it installed for a few weeks but im very impressed in the build quality ,power, and ease of installation of this amp . a great price for a quality item. front channels driving a pair of pioneer 6.5's. rear channels driving a pair of 8inch subs. amp at 75% gain with more to spare !

Pros: easy to install, great price in its class . plenty of clean power. well packaged and timely delivery.

Cons: mounting fins are plastic , not metal like the rest of the amp chassis. not a big deal, just dont over-tighten. i mounted mine vertically and its fine

Sound Ordnance™ M-4075

Written By jeff, hurley, ms on Wednesday, February 01, 2012

Crutchfield Customer Review (What's this?)

good amp with good power for the price

Pros: sounds really good and good power

Cons: the shell is made of plastic, be carefull when bolting it down


Written By CWalker, Gainesville,VA. on Friday, December 23, 2011

Crutchfield Customer Review (What's this?)

This amp does have punch. Had to replace the original terminal set screws for some M6x1.00 allen style(socket) set screws for a stronger connection. Also added spacers to get it off of the floor. Sounds fantastic.

Pros: The power

Cons: Wire terminals, Amp mounting, Cooling.

Wow! This has been a great amp

Written By MattC, Portland, OR on Wednesday, August 31, 2011

Crutchfield Customer Review (What's this?)

I bought this amp to power two front speakers and a subwoofer (Infiniti Reference 8") in my Eurovan. Couldn't be happier with it.

I am very impressed with its performance. This amp is a great value. When you bridge two channels as I did, you get 240W of power which is awesome for a small/mid sub. I have been using it for about 6 months now and just loving the sound, er, power it puts out. Does not get hot, even after blasting for 3 hour trips which I regularly do. I plan to get another one for my second car.

Installation was straightforward but tricky in my case as I needed to put it under the dash. I was tempted to mount it upside-down. Bad idea though, as generated heat would rise back up and risk cooking the circuit board. I had to make a few custom brackets--and ended up breaking one of the plastic endcaps while mounting the screw. NOTE: the two chrome-looking endcaps, including the mounting screw standoffs are plastic. I don't like that. I was much better off without the endcaps, which are easy to remove (reducing length by about an inch.) I recommend tossing these and bracketing into the sides, using the screws which hold on the endcaps.

I built a subwoofer box and console to fit between the seats in my Eurovan Camper, and 8" was the biggest sub I could fit. I didn't expect much, but OMG cannot believe the tight bass I get. Hits hard and fills the huge cabin. Shakes the mirrors, and I had to pad my license plate holders to keep the vibration noise down.

Good Product

Written By D, Minneapolis, MN on Wednesday, July 20, 2011

Crutchfield Customer Review (What's this?)

I bought this to power 4 component speakers and a pair of tweeters. After a pretty straight forward install the speakers really shine! They get nice and loud to really fill out the car with bright sound.

The amplifier is installed in my trunk and does not get hot and I have all the gains set at half.

As far as aesthetics, the amp has a nice chrome trim with a glossy black body. It is heavy and has a sturdy feel to it.

It came packaged with a pair of cheesy chrome coated plastic dog tags with the company's initials.

I am impressed with this off-brand amplifier and will be looking at them for any future car audio needs.

Great Starter Amp

Written By KFitz, Columbia, SC on Saturday, July 02, 2011

PROS: You couldn't ask for a better amp at this price. Puts out plenty of clean power for any component or 2-way speakers. I have under seat with little room and still runs cool and have had no problems.

CONS: Amp is pretty big and limits your possible locations. Also, you must use 8ga cable and nothing bigger, it will not fit and with this power don't run 10ga. Connection points face downward rather than outward like most other amps. This is a little frustrating during install, and wires can get bent went mounting amp that has little clearance below the amp. I would recommend mounting brackets so it will raise the amp an inch of the floor.

Great amp Great Price

Written By Brandon S., Oregon, OH on Wednesday, May 04, 2011

Crutchfield Customer Review (What's this?)

I have this amp powering a set of Polk Audio 3-way speakers in my rear deck
and a set of Kenwood components in my doors. The amp delivers crisp clean
signal and power to my speakers. The HP filters work as designed and tuning
was fast simple ant easy. I don't have any problems accessing the adjustment
dials with the end caps installed and the amp mounted on the back of my rear
seat. I even have a set of RCA's going from this amp to my mono-block
powering my 2 subs. This amp is more than I could ask for and thats a great
thing. I love this amp and I really love the price!!!


Written By Davey, Salt Lake City, UT on Thursday, February 24, 2011

Crutchfield Customer Review (What's this?)

Overall the quality of this amp is pretty good and produces clean power and clear sound. Couple things I found that aren't favorable revolve around the design and construction of the case. Why make the top be an overhanging annoyance that blocks any possibility of actually seeing the settings or connection points. It's also a poor design that the 4 mounting legs telescope out, and are made of such cheap plastic that tightening down the screw on anything other than a perfectly flat surface will result in it breaking.

Amazing 4 CH AMP

Written By DavidG, Loveland, CO on Tuesday, February 22, 2011

Crutchfield Customer Review (What's this?)

This Amplifier has truly exceeded my expectaions! It sounds better than my Dads
$400.00 Amp from Alipine....Thanks Sound Ordanance for building a superior Amp for
the money!

Sound Ordnance™ M-4075

Written By rockstar, hawaii on Wednesday, January 26, 2011

Crutchfield Customer Review (What's this?)

This amp slams. Have it powering four kicker 6" in my doors and rear deck in 2
channels and my Kenwood 12" box bridged. This setup slams and I don't even have the
gain up to half yet. Would recommend this amp for any setup.

Outstanding Amplifier

Written By Chuck, Omaha, NE on Monday, January 17, 2011

Crutchfield Customer Review (What's this?)

I researched many amps both on this site and on many others. My goal was to get a 4 channel amp installed for under $200. I am pushing a pair of Alpine 3 way 6x9's and the kenwood components. The sound is crisp and the power is great for an amplifier at this cost. The frequency controls are good even though I run at full I tried both HP and LP and they worked as described. Yes some parts are plastic but the quality of craftsmanship is great. The only bad points that I found were that the amp mounts by the removable end caps which makes no sense to me as once the amp is mounted I was not able to get to any of the controls so taking the caps off at that point would have been helpful but I could not. Also the RCA' s are on one end of the amp while the power, ground, and speaker outputs were on the other. Just an idea would be to keep the speakers away from the power and ground by putting the control knobs on the end with the power and ground while keeping the speaker output with the RCA inputs. Just a thought as it did not cause any issues with noise. I wondered why not just put everything on one end and allow for easier installation but again these are only annoyances with installation and not any knock on its looks or performance. I will definitely be buying the monoblock amp if I hook up a subwoofer but for now this amp provides every bit of the power I need to have an outstanding stereo in my car.

Dramatic Improvement

Written By Sean Q, Atlanta, GA on Thursday, January 13, 2011

Crutchfield Customer Review (What's this?)

I just finished installing this amp in a Mazda Tribute. It is driving Polk (db 5251) component speakers up front and Polk MM 571 in the rear doors. My receiver is an Alpine CDA 105 so sound processing is not a problem. The amp is replacing an 800.4 that I bought based on my budget at the time. The speakers were loud but the sound lacked the mid-range and mid base quality I was expecting. I assumed it was either the limitations of the cars interior combined with the smaller size of the speakers or the amp.

I ordered the sound ordnance amp based on the other reviews but I was concerned I was going to make another budget amp mistake. I should mention that one of the MM571 speakers would crack every now and then at certain base frequencies which was unnerving considering they are suppose to handle a decent amount of power. I have not had a chance to fully tune the system but I can already hear a dramatic difference in the sound quality. The depth and richness of sound is so much better and so far no cracking. Obviously, I will need time to fully evaluate the quality of this product but out of the box. I would snap one up before they realize they are being robbed!

A Very Solid Amplifier

Written By Steve D, Eureka, CA on Thursday, November 18, 2010

Crutchfield Customer Review (What's this?)

I needed a four-channel amplifier to power the rear speakers and a subwoofer in my
Mercury Villager. I am happy to say that this amplifier really delivers the goods at a very
reasonable price! I am using it to power two Infinity 6832 coaxial speakers and an
inexpensive 12-inch woofer I had sitting in my garage. This amplifier really makes
the Infinitys come to life. The amp also supplies an abundance of clean punchy bass to
the subwoofer, which is installed in an acoustic suspension enclosure.

This amplifier has a much warmer sound than others I have owned. So if you cherish
the sound of analog audio as much as I do, then you will love it! It is also the easiest
amplifier to hookup that I have ever seen. The connectors on the amplifier accept bare
wires, so you do not have the hassle of having to install crimp connectors. The amp has
a ton of set-up options thanks to the on-board electronic crossovers and bass boost.

When I first started to install this amplifier, I was not aware of just how large it is! I was
planning to install it beneath the driver seat, but when I saw how cool it looked, I decided
to install it on the floor of the van between the two front seats.

In a nutshell, this amplifier was a bargain! The warm sound from it makes Pink Floyd
and jazz music sound like a million dollars in my car! Cudos to Crutchfield for providing
such a solid amplifier for a bargain price!

M-4075 Sound Ordnance Amp

Written By Terry H, Henry,VA on Saturday, October 30, 2010

Crutchfield Customer Review (What's this?)

Great amp for the amount of power needed for my upgraded system Thanks

m 4075

Written By PhilD, Illinois on Monday, September 20, 2010

Crutchfield Customer Review (What's this?)

got this amp in exchange of a kicker zx 200.4 and i expected it to outperform the kicker
considering its twice the power and it did. The amp looks great, plays with no noise, and
sounds crystal clear on my sound ordnance 6.5 components, along with my very old, but
trusty jl audio vr 5.25's on the front channels, and the rear channel bridged to a sound
ordnance vented 12. Very nice inexpensive little set -up.

Sound Ordnance™ M-4075

Written By Anonymous, Aldie, Va on Monday, August 30, 2010

Crutchfield Customer Review (What's this?)

ok. this install was for a 2003 mdx.

great amp for the price, looks sharp, and the controls are very easy to figure
out. installation was a breeze

rather heavy, the amp heats up really fast, and my biggest complaints

-the silver cover is PLASTIC??? If you want a quality, dont skimp out.
-you need a long drill bit to screw the screws in through the plastice which by
the way, keeps the amp in place.
-my amp picks up sound from the engine. i called crutchfield support, they told
me it was a ground issue. thats odd, because i dont get that with my other amp.

overall, I would skip this amp for a more known brand. sorry crutchfield.

Awesome amp for its price!

Written By Anonymous, Williamsport, PA on Thursday, April 29, 2010

Crutchfield Customer Review (What's this?)

For the price... you cant go wrong. I have this amp powering 4- Infinity Kappa 682.9cf in my 2008 Mazda 3. I first had the speakers hooked up to the factory head unit. I was highly disappointed... After talking to one of my buddies, they recommended powering the speakers with an amp. So i jumped on Crutchfield to see what they had in the way of 4-Channel amps. I found this one and decided to give it a try, and I made a very good decision. It powers my speakers perfectly and has a lot of tuning options to get full range speakers sounding perfect! You cant go wrong with this amp!