JL Audio Slash v2 Series 300/4v2

4-channel car amplifier
75 watts RMS x 4

  • JL Audio Slash v2 Series 300/4v2


  • JL Audio Slash v2 Series 300/4v2


  • JL Audio Slash v2 Series 300/4v2

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Item #: 1363004V2

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Our take on the JL Audio Slash v2 Series 300/4v2

by Buck Pomerantz
JL Audio

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.

Consistent power for performance you can count on

Control panel

JL Audio's Slash v2 amplifiers aren't just powerful, they're smart. As your battery voltage fluctuates while you drive, the Regulated, Intelligent Power Supply™ system maintains steady, consistent power at any impedance between 1.5 and 4 ohms and at any voltage between 11 and 14.4 volts. You'll get all the power, all the time, even with a wide range of speaker combinations.

Pure power for your system

The 300/4v2 4-channel amplifier puts out 75 watts RMS per channel to your system, and JL Audio's patented Class-AB amp circuitry delivers exceptional, natural sound with extremely low distortion. The cast aluminum heatsinks dissipate heat quickly, giving these amps long lifespans and reliable operation. Variable high- and low-pass filters give you precise level of control needed to maximize the performance of your speakers or subwoofers.

Minimize external noise

Differential inputs for low noise

JL Audio amps use "differential-balanced inputs" to isolate the signal's ground from the chassis ground, reducing noise and making Slash v2 amplifiers compatible with almost any system, including most factory radios.

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  • 4-channel car amplifier
  • 75 watts RMS x 4 at 1.5 to 4 ohms
  • 150 watts RMS x 2 at 3 to 8 ohms
  • Regulated, Intelligent Power Supply system
  • differential-balanced inputs
  • variable high- and low-pass filters (50-5000 Hz, 12 or 24 dB/octave)
  • Absolute Symmetry™ Class-AB amplifier design
  • MOSFET power and output stages
  • speaker- and preamp-level inputs (speaker-level input requires an optional adapter)
  • 4-gauge power and ground leads and a 40-amp fuse recommended — wiring and hardware not included with amplifier
  • no onboard fuses — when installing multiple amps in a system, an additional 40-amp in-line fuse between the distribution block and the amplifier is recommended
  • 13-7/16"W x 2-5/16"H x 10-1/16"D
  • warranty: 2 years
  • Our 60-day money-back guarantee

Hands-on research from the Crutchfield Labs (what are the Labs?)

Features and Specs
RMS Power Output (Watts x Channels) 75 x 4
Peak Power Output (Watts x Channels) N/A
Power at 2 Ohms (Watts x Channels) 75 x 4
Bridged Power (Watts x Channels) 150 x 2
Minimum Impedance Bridged 3
Minimum Impedance Unbridged 1.5
Best Frequency Response 5-30k Hz
THD at Rated RMS Power 0.03%
Signal to Noise Ratio 109 dB
Input Voltage 14.5v
Amplifier Class AB
Low-Pass Crossover Frequency 50-5k Hz
Low-Pass Slope (dB/octave) 12/24 dB
High-Pass Crossover Frequency 50-5k Hz
High-Pass Slope (dB/octave) 12/24 dB
Bass Boost No
Bass Boost Frequency N/A
Fan Cooled No
Fuse Rating 40
Speaker Level Inputs RCA (adapter req)
Preamp Outputs No
Width (inches) 10-1/16
Height (inches) 2-5/16
Depth (inches) 13-7/16
Parts Warranty 2 Years
Labor Warranty 2 Years
Product Research
What's in the box?

Download owner's manual

  • Four-channel full-range amplifier
  • 2.5mm Hex-wrench
  • Owner's Manual

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 open the box, verify contents, 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.



Four-Channel Full-Range Amplifier: The JL Audio 300/4v2 is a class A/B four-channel, full-range amplifier that is rated at 75 Watts RMS x 4-channel in 1.5 to 4-ohm at 20 to 20kHz with a signal-to-noise-ratio of 108.5 dB and a total harmonic distortion of 0.03% while receiving 11 to 14.5 Volts. The amplifier can also be bridged to output 150 Watts RMS x 2-channel in 3 to 8-ohms.

R.I.P.S. (Regulated, Intelligent Power Supply): R.I.P.S. stands for "Regulated, Intelligent Power Supply" and is a central feature of the JL Audio's Slash v2 amplifier. The JL Audio R.I.P.S. System ensures consistent power delivery over a wide range of battery voltages and load impedances. This technology provides optimum power at any impedance level between 1.5 ohm to 4 ohm per channel and at any vehicle voltage level between 11V and 14.5V:

  • Regulated Power Supply: "Regulated" means that the power supply adjusts its operation so as to maintain the amplifier's rated power output and low distortion operation over a wide range of vehicle voltages (11V-14.5 V). This allows the JL Audio Slash v2 amplifier's the rail voltage and clean power output to remain stable in real-world car-audio systems, resulting in superior fidelity and stability.
  • Intelligent Power Supply: The "Intelligent" portion of the R.I.P.S. System is a circuit that actually monitors output current to optimize the amplifier's output power over a wide range of load impedances (1.5 ohm to 4 ohm per channel). The R.I.P.S. System detects the actual impedance being driven and adjusts output rail voltages to deliver optimum output. The entire process is seamless, automatic, and results in incredible dynamics for satellite channels and consistent power output for a wide range of subwoofer configurations. It also takes into account the real impedance of your car-audio system, rather than relying on often inaccurate assumptions based on a speaker's rated impedance.

Monolithic RealSink Plus Advanced Heat Management: This Slash v2 amplifier features a real cast-aluminum heat sink with vertically-oriented fins that are highly effective at dissipating heat from the amplifier via convection and radiation. The design of this heat sink is achieved through extensive finite-element analysis, resulting in an amplifier that keeps cool under the most demanding conditions. If a Slash v2 amplifier should ever reach an unsafe temperature, our unique Advanced Rollback Protection circuit also adjusts power until the amplifier cools down, without ever shutting your music down. As an added cosmetic benefit, the cast-aluminum end-caps of the Slash v2 amplifier replicate one-half of a full heat sink fin so that when two or more amplifiers are mounted end-to-end, you get a totally seamless custom look.

Absolute Symmetry A/B Circuitry: The JL Audio full-range amplifier benefits from a patented technology called Absolute Symmetry to deliver amazing fidelity with extremely low distortion over a wide range of load impedances. The JL Audio amplifier features a revolutionary Class A/B circuit that employs identical N-Channel MOSFET transistors for push and pull with true buffering from the load impedance. This is accomplished via a patented circuit that reverses the operation of one of the transistors in each pair to achieve absolute power symmetry and extremely low distortion over a wide range of load impedances.

Differential-Balance Inputs: The JL Audio amplifier features differential-balanced input architecture to effectively control noise and ensure compatibility with a wide variety of source units, including many OEM systems. Without resorting to line output converters, you can directly connect most OEM source units to the JL Audio amplifier without creating any noise or compatibility issues. Unlike conventional single-ended inputs, the differential-balanced design does not connect one side of the audio signal to chassis ground.  This eliminates any voltage sensitivity between one input terminal and ground and greatly reduces the incidence of alternator whine in a typical car audio installation. The Slash v2 amplifier provides range switching on each of its inputs via the "Input Voltage" switch. This permits connection to a wide range of source voltages while retaining excellent sensitivity setting precision.

Note: You will need two speaker wire to RCA adaptors (136XDCLR2S, sold separately) to connect this amplifier to your headunit via speaker-level.

Protection Circuitry With Status Indicator Lights: There are three status indicator lights on the top of the amplifier:

  • Power (Green): This LED lights green to indicate that the amplifier is turned on and operating normally.
  • Thermal (Red): This Red LED lights to indicate that the amplifier has exceeded its safe operating temperature, putting the amplifier into a shelf-protection mode, which reduces the power output of the amplifier. The red light will shut off and the amplifier will return to normal, full-power operating mode if the heat sink temperature drops back to a safe level.
  • Low Ohm (Amber): This amber LED lights to indicate that the impedance of the speaker load connected to the amplifier is lower than the optimum impedance load range for the amplifier. When this light is on, a protection circuit engages and reduces the power output of the amplifier. The amber indicator will also light when a short-circuit is detected in the speaker wiring.

Note: There is only one condition that will shut down the 300/4v2 completely and that is if the battery voltage of your vehicle drops below 10 volts.


Simplified Gain Setting: The amplifier's R.I.P.S. feature also allows for easy gain setup. Because the amplifier will always deliver the same amount of power within its operational range of impedances and supply voltages, the maximum, unclipped output is very predictable. This makes setting the gain level of the amplifier via the input sensitivity control very simple. All you need is Digital AC Voltmeter (142TK12V, sold separately) and a Test CD Disc (503CD104, sold separately) with a sine-wave test-tone recorded at 0 dB reference level in the frequency range to be amplified for that set of channels (50 Hz for subwoofer channels, 1 kHz for a midrange application).

Active Crossover: The Slash v2 amplifier provides a comprehensive crossover network to fine tune your system effectively and accurately. The variable filter design employed in the Slash v2 amplifier crossover sections allow you to seamlessly switch slopes, easily change filter frequencies and address what frequencies the preamp outputs will pass. The 300/4v2 offers the following independent crossover adjustments for the front and rear channels:

  • Filter Mode: The amplifier features a Full-Range, variable Low-Pass or variable High-Pass filter mode for the amplifier's preamp input section.
  • Variable Frequency: Fully-variable frequency selection from 50-500 Hz on full-range channel filters with frequency range switch in "x1" position. Selecting "x10" on the frequency range switch multiplies the filter frequency times ten to allow cutoff frequencies between 500 - 5000 Hz.
  • Switchable Slope on all filters:12dB/octave Butterworth or 24dB/octave Linkwitz-Riley alignments allowing for more precise integration of subwoofer and speaker channels.


Power and Ground: The JL Audio amplifier's set-screw Power and Ground connections are designed to accept 8 to 4 AWG power wire.

Remote Turn-On: The Slash v2 amplifier's set-screw turn-on lead will accept 18 to 8 AWG wire.

Speaker Outputs: The 300/4v2 amplifier's eight set-screw speaker terminals will accept 16 to 8 AWG speaker wire.

Preamp Inputs: The amplifier features two sets of differential-balanced RCA jack inputs. The amplifier's input level can be set independently for the front and rear channels to Low (200mV-2V RMS) when connecting the amplifier to a low-level preamp signal or set to High (800mV-8V RMS) when connecting the amplifier to a high-level speaker signal.

Note: All inputs, outputs and controls are located on the front side of the amplifier to make installation of the amplifier simple and neat.

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JL Audio Slash v2 Series 300/4v2 Reviews

Average Customer Review:

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5 out of 5

JL Audio Slash 300/4

Written By Jason M, Orange County, CA on Thursday, May 24, 2012
Crutchfield Customer Review (What's this?)
I bought this amp because of JL's reputation. A little pricey though. Just installed it today, and have it hooked up to a Kenwood Excelon KDC-X796 head unit and Polk Audio db6501 component's and db651s. Amp gets alittle hot after running it for awhile( its in my trunk) I wish I could of installed it under my seat as I always drive with my windows down ( cooll air flow).
Its JL Audio!
Alittle Pricey $$$
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5 out of 5

JL Audio Slash v2 Series 300/4v2

Written By Thomas, Corpus Christi, TX on Friday, March 27, 2009
I have this 300/4v2 powering Polk Audio MM6500 & MM5251 speakers and
it sounds nice and clear. The amp is installed under the drivers seat and it
does get a bit hot so it does need room around it to allow some air to cool
it down. It allows the speakers to play clean from low volume to quite loud.
3 out of 4 people found this helpful
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4 out of 5

JL Audio Slash v2 Series 300/4v2

Written By Jim, phoenix, az on Saturday, October 25, 2008
This is a good solid clean sounding amp but it's setup is a little bit different (read the manual before you start, especially the part about impedance matching). I have this amp pushing JL C5's and I couldn't be happier with the performance I'm getting out of it. The built in cross overs also work very well.
4 out of 6 people found this helpful
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5 out of 5

Blows Alpine PDX AWAY

Written By Shawn, Elgin, IL on Monday, October 20, 2008
Crutchfield Customer Review (What's this?)
I went thru 3 Alpine 100.4 amps before finally purchacing this one...this amp is so awesome and so well made. Def the best amp ive ever had.
2 out of 4 people found this helpful
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3 out of 5

heres the truth

Written By bhightower, marion, al on Thursday, September 25, 2008
Ive been in car stereo for years and have owned or installed most every brand out there. Jlaudio makes some of the best stereo equipment ive ever seen ! HOWEVER, there slash series amps arent as dynamic as i like my amps to be. If u are using it for subs and u like very punchy bass then these amps perform very well. Bass drum beats sound amazing ! Mids and highs are where their amps fall short. Snare drums and symbol crashes sound a bit weak. Let me put it this way, country music sounds good with this amp but rock such as Creed or Angels and Airwaves sound better with more dynamic drum beats and better sounding symbol crashes. I love rock music and i DEMAND the very best sound from the drums, symbols and guitar ! Trust me when i say use jlaudio amps for subwoofers but go with something different for mids and highs ! Rockford fosgate is a better choice on the mids and highs end. Dont get me wrong these amps dont sound bad by any means but if u try them for your component speakers then you'll be missing out. Hopefully the new hd series amps will be better. My speaker werent the problem because i was using JLaudio ZR components and an Alpine head unit
22 out of 42 people found this helpful
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5 out of 5

Music at a whole new level!!!

Written By Fernando, Long Beach, CA on Monday, July 14, 2008
I recently picked up this amp for my Mustang. I researched a lot of amps before making my decision. I finally decided to pay a little extra and see what this amp was made of. AMAZING I must say. I have it pushing Polk/MOMO 5-1/2 components and Polk/MOMO 5X7's and it produces the best music I have ever heard. Not only is the music very clear but its very loud. The louder I go, the tighter and more precise the music is. This amp is very underrated and most definetly worth the price. If you are serious about music quality in your vehicle I definetly recommend this amplifier.

P.S. To fully benefit from this amp I suggest tuning it with a test CD and a voltmeter just as the owners manual suggest.
11 out of 11 people found this helpful
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5 out of 5

Absolutely AWESOME!!!!

Written By KYHO, Great Falls, MT on Sunday, April 20, 2008
I am running this amplifier to JL XR components in the rear and components in the front. In the past I have run Alpine
amps and loved them. I heard the JL amp in a local shop and was just
shocked at the difference in sound quality.

If sound quality is what you are after, this amplifier is for you. Once you
get your settings right you can turn your stereo up and it will hurt your ears
before it distorts (no kidding my ears were ringing when I got out of my
car). You will pay a little more for this amplifier but in my opinion it is well
worth it. The sound quality is unsurpassed.
18 out of 20 people found this helpful
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5 out of 5

JL 300/4v2

Written By Tyler, Saratoga NY on Thursday, January 31, 2008
This is by far the best four channel amp I have ever owned. It is incredibly efficent with regard to current draw and power reproduction. It produces much more RMS than listed because of the R.I.P.S power supply which is rated at 12.6 volts vs most amps which are rated at 14.4. This amplifier stays super cool under demanding playing conditions such as extented period of time or high temps. Also delivers the cleanest audio I have ever heard from a 4 channel amplifier. JL's amps are excellent performers and they also offer pleanty of flexibility. This amplifer would also work well running it in 3chanel mode using the front two to run component speakers and bridging the rear two to run a sub. There are not many amps that could deliver an entire system from a single power source. Highly reccomended.
44 out of 48 people found this helpful
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For a more in-depth review and enhanced detailed information on the JL Audio Slash v2 Series 300/4v2, please visit the Crutchfield website product page (/ISEO-rccbcspd/p_1363004V2/JL-Audio-Slash-v2-Series-300-4v2.html ).