Why Choose Crutchfield?
Great gear and expert advice
Our experts help you pick the ideal gear for your needs.Meet our advisors
Free tech support for the life of your gear.Read about our one-on-one expert help
You may return items that are complete and like new for any reason within 60 days.See the details of our return policy
Earn one point for every dollar you spend and use those points to save on future purchases.Get full details on Crutchfield Rewards
Deep discounts on car installation gear
We offer vehicle-specific installation instructions, dash kits, wiring harnesses, and speaker accessories at deeply discounted prices with car stereo and speaker purchases. Available for most vehicles.Learn more
Trusted since 1974
Our customers have trusted us with their business, and they’ve helped us win awards for our service.Check out our most recent awards
The manufacturer’s warranty always applies.See more details
Sound Ordnance M-4075
4-channel car amplifier 75 watts RMS x 4
Our take on the Sound Ordnance M-4075 by Crutchfield's Buck Pomerantz
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.
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.
dennis, Archer City Tx
What's in the Box:
- 4-Channel amplifier with two 30A ATC blade fuses inserted
- Spare 30A ATC blade fuse
- 4 Self-tapping screws (5/8" length)
- 4 Split lock washers
- 4 Flat washers
- Owner's Manual
- 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
Sound Ordnance M-4075 Reviews
Average Customer Review(s):
Thanks for submitting your review
Features and Specs
|RMS Power Output (Watts x Channels)||
75 x 4
|Peak Power Output (Watts x Channels)||125 x 4|
|Power at 2 Ohms (Watts x Channels)||120 x 4|
|Bridged Power (Watts x Channels)||240 x 2|
|Minimum Impedance Bridged||4|
|Minimum Impedance Unbridged||2|
|Best Frequency Response||12-25k Hz|
|THD at Rated RMS Power||1%|
|Signal to Noise Ratio||88 dB|
|Low-Pass Crossover Frequency||50-250 Hz|
|Low-Pass Slope (dB/octave)||12 dB/oct|
|High-Pass Crossover Frequency||80-2k Hz|
|High-Pass Slope (dB/octave)||12 dB/oct|
|Bass Boost||0, 6, 12 dB|
|Bass Boost Frequency||45 Hz|
|Speaker Level Inputs||No|
|Preamp Outputs||1 pair|
|Parts Warranty||3 Years|
|Labor Warranty||3 Years|
Power Ratings: The Sound Ordnance M-4075 is a 4-channel Class AB amplifier with an RMS power rating of 75 watts per channel into 4 ohms, and 120 watts per channel into 2 ohms. The amp can also be bridged into a 4-ohm load for a power rating of 240 watts (x 2). Power ratings are measured with an input power of 14.4 volts.
Crossovers: The M-4075 is equipped with both high-pass and low-pass crossovers. The front channels (channels 1 and 2) and the rear channels (channels 3 and 4) have separate crossovers. You can set the low-pass cutoff frequency between 50Hz and 250Hz, and the high-pass cutoff frequency between 80Hz and 2 kHz. Separate switches let you select low-pass, high-pass, or full range operation for the rear channels, and high-pass or full range for the front channels. The crossovers have a 12dB per octave slope.
Bass Boost: The amplifier has a bass boost switch, labeled Super Bass, to give small subwoofers more volume in the low frequencies. You can select the amount of boost with the 3-way switch: 0dB, 6dB, or 12dB. The Super Bass feature is available for the rear channels only.
LED Indicators: The M-4075 features two LED indicators: a green LED that illuminates when the amp is powered on, and a red LED that illuminates when the amplifier is in protect mode due to overheating or a short circuit in the speaker wire.
Removable End Caps: The end caps on the M-4075 are removable with a 3mm Allen wrench (not supplied) to make it easier to attach the power and speaker wires.
Power Connections: The power and ground connections are set screw terminals that will accommodate up to 8-gauge wire. (An 8-gauge amplifier wiring kit is recommended.) The remote turn-on terminal is a set screw terminal that will also accept up to 8-gauge wire. A Phillips-head screwdriver (not supplied) is required to tighten/loosen the terminals.
Speaker Connections: The speaker connections are set screw terminals that will accommodate up to 8-gauge wire. A Phillips-head screwdriver (not supplied) is required to tighten/loosen the terminals.
RCA Inputs and Outputs: The amplifier features two pairs of stereo RCA inputs for connecting your head unit--one pair for the front channels and one pair for the rear channels. If your head unit only has one pair of preamp outputs, you can feed all four amplifier channels by connecting optional Y-adapters. (You will lose front-to-back fader capability if you connect the amplifier using Y-adapters.) There is also a pair of stereo RCA outputs for feeding the preamp signal to another amplifier, if needed.
Fuses: The M-4075 features two 30-amp ATC 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.
Product reviews from the Crutchfield Labs
by Video Team
Make your music sound lively and vital with a Sound Ordnance amplifier. Watch this Crutchfield video to see what these rugged, value-packed amplifiers have to offer.
5 questions already asked
You'll be just fine working with that wiring kit! I ran mine on 12 gauge wires and a 20A fuse, with gain at about 60%, and no problems! [ CHRISTOPHER B Apr 02, 2015 ]
The amp is turn on by the 12V connector from your radio. per the manual "The voltage rating of the fuse depends on the power consumption of the connected devices of the car audio system." [ DOUGLAS H Apr 01, 2015 ]
8 gauge. Do yourself a favor and stay away from this amp. It's big and it's under power. Go with alpine/Rockford/JL. [ ERIC Mar 01, 2015 ]
Marvin, this amp can use up to an 8 gauge wire. Thats what I used when installing it and I have not had any issues. This is a good reliable amp for the money. [ PAUL Feb 22, 2015 ]
I forwarded your question to an Advisor and they responded with the following: We can certainly help pick out speakers, but in order to do so we would need more information from you regarding the vehicle they are going in and tonal preferences. If you would like to discuss further you can contact an Advisor directly by phone (1-800-324-9695) or online chat. [ Krissy Feb 10, 2015 ] Staff
I bought this amp a while back because my cheapo Sony xplode amp died. It was what seemed like the most value for what it cost. So far it has performed just fine. I haven't had any trouble with it at all. It is powering four 5 1/4 speakers as well as two 7/8 tweeters and is paired with a sound ordinance mono channel amp powering a 12" sub. The system sounds great and I would recommend this amp however I am comparing it to the Sony xplode which is the only other amp I've owned so just keep that in mind. [ LINCOLN Dec 17, 2014 ]
This thing is huge and it doesn't push hard. My alpine HU pushing harder. I paired it with 4 Infiniti 6 1/2. I would recommond you to spend a little bit more and get a real decent 4 channel amp. JL, Alpine or Rockford. Enjoy!! [ ERIC Dec 16, 2014 ]
I'm happy with the Sound Ordnance amp. It powers 4 6 x 9 speakers in my Bronco and has plenty of power. [ JERRY Dec 16, 2014 ]
I forwarded your question to an Advisor and they responded with the following: You'll need an 8 gauge kit such as this one: http://www.crutchfield.com/p_142PA8BX/EFX-PA8BX-Wiring-Kit.htmlIf you would like to discuss further you can contact an Advisor directly by phone (1-800-324-9695) or online chat. [ Krissy Dec 01, 2014 ] Staff