When i hook up the amp it sounds distorted on all 4 outputs. JL audio 300*4

Re tune your amp

here is a manual for your subwoofers: http://mobile.jlaudio.com/pdfs/8-12W6_BDS.pdf

use the wiring diagram for 1.5? (1.5ohm) with 2 speakers. the diagram for 3 speakers will not work, because it would bring the load down to 1 ohm, and the amp cannot go below 1.5 ohm.

to set up the amp:

under "preamp output section", on the "output mode" switch, select "amp filter"

to set up the levels: start with the amp gain pretty far down- with the input voltage on low for line level outputs from the deck, and on high for speaker outputs from the deck. now turn your cd deck as far up as it will go until it distorts, then turn the cd deck down to just where it stops distorting. now, you can start to turn up the gain on the amp.

on the filters, youll prolly want the cutoff filter around 100hz @ 24db slope. start with the infrasonic filters off, but, if you do get into them, try centering between 30 and 60hz on either, and, possibly dropping the cutoff filter to 80hz.

1) Check the Subwoofer for continuity - At the subwoofer, one at a time, test the terminals for Continuity using your Digital Multi-Meter; if your DMM doesn't have a Continuity test, use the Resistance, or Ohms, test and check for Resistance in the Subwoofer Coil (be sure to disconnect the subwoofer wiring before performing these tests).
2) If they test out good, hook the wires back up and test the terminals at the terminal cup or at the Amp hookup if you didn’t use a terminal, don't hook it up to the amp yet. Sometimes the wiring inside the box can be a problem if it has come loose, or isn't making a great connection.
3) If you have a Sub or multiple Subs with Dual Voice Coils, or multiple Subs with Single Voice Coils, make sure your wiring is correct by checking here:
http://www.the12volt.com/caraudio/woofer_configurations.asp
4) Make sure there are no Hi-Pass filters, crossovers, or multi Channel switches enabled.
5) Replace your RCA cable/s with known working RCA cable/s from the Source/Head Unit to the Amplifier/s.
6) Check your Head Unit settings; make sure the Bass is turned up and/or the Subwoofer setting is turned On.
7) If you are still getting no or low output, try plugging in an MP3 player or CD player using a headphone to RCA adaptor and check for sound output. If there is still no or low output, your Amplifier outputs are probably burned out.


I’m happy to help further over the phone at https://www.6ya.com/expert/jeremy_69f3cc28d95bf514

Dang man you roasted it, take it in and get it replaced.Check the gain on the amp try it at 1/3 to 1/2 gain and dont crank up the bass boost all the way try it at like 2/3 that should clean up your sound and cut down distortion-distortion kills subs by heat.

You should definitely upgrade the power wire to the sub amp to 4 gauge -absolutely your choking your amp its starving for current-poor thing is starving !!!!!!!

Check your fuse at the battery. While AGU glass fuses "look" good, when you read the voltage AFTER the fuse, you can only be getting 5 volts or so. I can't tell you how many times I have seen this.

Larry T
Winona Lake, IN
http://www.cybersoundsaudio.com/cybersounds/vehiclepics.html

I had the same amp! It is the JL 300/4 and one of the chanels came in really fuzzy. It sounded as if the the wires were touching during my installation. I called JL and a JL authorized dealer it would have costed me 190 dollars total to get the amp fixed. Instead I opened up the amp to see if anything looked out of the ordinary. When you open the amp, see if the green fuse looking things are aligned. If they are not aligned then straighten them out. I think they had gotten out of place from being dropped becaue I baught my amp used. My amp works perfectly now!

This is no joke man, I did this just yesterday and was really excited to save 190 bucks. I'm not a technical guy or anything all I know is the green things are located behind the out puts inside the amp.

This can happen if the amp has an internal fault such as a shorted output transistor.

It sounds like you have a broken output filter inductor in the amplifier. You should be aware that the speaker outputs of the amp are biased at ~40v DC and can give a good shock if you touch the speaker wire while you're grounded (touching the body of the vehicle).

 

When you connected the speaker as you did, I would have expected the speaker to move in or out and remain there while the wire was connected to the housing of the amp. I'll assume that the amp was screwed down to the chassis of the vehicle. If it wasn't, you may have more than one problem.

Nothing should have been damaged. I would assume the speaker output shorted in one way or another...did you have a speaker hooked up? You most likely blew the output transistors and they ALL need to be replaced as one going bad will kill the rest since they're so sensitive. At least the PSU, seemingly, wasn't damaged. Contact www.audiotekx.com, ask for Jason, he's excellent at repairing amps and has great pricing.