Subwoofer randomly sounds like thunder (JL 1000/1 repair?)
A few weeks ago my JL w6's started cutting out and then rumbled sounding exactly like thunder, then return to normal. I checked all the connections and they all look and feel solid. What could be causing this? Thanks.
Revisiting this issue 4-10-2012
I think the JL 1000/1v1 is the problem. See latest posts. Thanks.
A few weeks ago my JL w6's started cutting out and then rumbled sounding exactly like thunder, then return to normal. I checked all the connections and they all look and feel solid. What could be causing this? Thanks.
Revisiting this issue 4-10-2012
I think the JL 1000/1v1 is the problem. See latest posts. Thanks.
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I'm running an alpine Iva-w505, JL 1000/1, and 2 JL 12" w6's im a sealed JL box. I installed it and what's a dmm?
I was concerned that the RCA shield ground in the amp may have been defective. That can cause symptoms similar to what you listed. If moving the RCA cables doesn't make a difference, the RCA shields on the amp are likely OK and it's likely that the RCA connectors on the cable are OK also.
DMM - Digital Multi-Meter
DMM - Digital Multi-Meter
O ok I do have a DMM. I agree that its got to have something to do with the RCA's. I remember the first time it happened was with my trunk loaded with crap for college. But last time it happened I pulled over and put the back seat down to move and pull on all the RCA's and power-grounds but I couldn't get the very loud rumbling to stop. The rumbling is usually proceeded with no sound from the subwoofer at all. Any ideas?
The subject line made it sound like it was intermittent. If it's constant, disconnect the RCAs from the amp. Does the rumbling stop?
It is intermittent. After it stops there is no sound for a couple minutes then it goes back to normal.
I'm gonna check the ground in the trunk again but it should be fine considering the other amp is not affected and both amps ground from the same ground block. The head unit is grounded through the ground wire on the stock HU connector.
I seem to be a magent for JL 1000/1 amps with dirty connections. If this is the amp running the subs then I'd suspect some dirty switch contacts as an issue. I've seen a bunch of these JLs that have this problem.
You may find whatever works best for you, but I usually use just a tad bit of contact cleaner to clean them, and then a Q-Tip loaded with WD40; a small drip of WD40 into the switch as best you can usually helps wonders. FYI I've had a Soundstream amp which came in with horridly bad switch contacts and WD-40 has been aiding the switch and running the amp in my car for 6+ months without problems.
You may find whatever works best for you, but I usually use just a tad bit of contact cleaner to clean them, and then a Q-Tip loaded with WD40; a small drip of WD40 into the switch as best you can usually helps wonders. FYI I've had a Soundstream amp which came in with horridly bad switch contacts and WD-40 has been aiding the switch and running the amp in my car for 6+ months without problems.
I know this thread is old (I'm the OP) but I am still having this frustrating issue. I gave up last summer but now I am determined to figure it out because I have some time.
I think I've narrowed it down to the JL 1000/1 amp. It is a 1000/1 v1, 5 years old, and mounted to the back of my rear seat in the trunk. I think you may be on to something Dr. Zeus about the 1000/1 being the culprit. It seems like (I could be wrong) that going over harsh bumps aggravates the problem (very LOUD feedback even if I pause the music and cutting out). Only shutting off the headunit, and therefore amps, durring a 5 - 20 subwoofer feedback episode will stop the feedback.
I'm suspecting a bad solder connection somewhere around the RCA input or the speaker output, inside the amp. I am going to open the 1000/1 very soon. Does anyone have any advice about what I should look for when opening the amp? Thank you.
I think I've narrowed it down to the JL 1000/1 amp. It is a 1000/1 v1, 5 years old, and mounted to the back of my rear seat in the trunk. I think you may be on to something Dr. Zeus about the 1000/1 being the culprit. It seems like (I could be wrong) that going over harsh bumps aggravates the problem (very LOUD feedback even if I pause the music and cutting out). Only shutting off the headunit, and therefore amps, durring a 5 - 20 subwoofer feedback episode will stop the feedback.
I'm suspecting a bad solder connection somewhere around the RCA input or the speaker output, inside the amp. I am going to open the 1000/1 very soon. Does anyone have any advice about what I should look for when opening the amp? Thank you.
Dude, don’t open the amp! Its unlikely that the problem you are having is from inside the amp. If you checked the RCAs and the speaker wires and none are shorted than the only logical solution is the Sub(s). Not necessarily bad. But may have leads touching or speaker wire inside the box arching. Or one Sub may have a bad coil and when it rubs it shorts out giving you a sudden burst of clipping (sounds like thunder)
If you open the amp you will not be able to tell what’s wrong unless there is speaker wire pieces that somehow got in there (doubt it)
Good luck
If you open the amp you will not be able to tell what’s wrong unless there is speaker wire pieces that somehow got in there (doubt it)
Good luck
Can you disable the input to the amp, either by turning the input gain to zero, or disconnecting the input cable and putting in a shorting RCA plug? Then see if you get the noise while driving over speed bumps or whatever does it reliably.
And you've verified the grounding is OK, I think? A marginal ground could lead to some kind of feedback. Be particularly wary of crimped terminals; a lot of people don't understand how to use a crimp tool, or use a lousy one.
But it could be an internal problem. If it occurs after a mechanical shock, that points to a mechanical problem more than a purely electrical one. Possibly an unsoldered lead, or cold solder joint. If there's harnesses that plug onto boards, try replugging them, maybe treat the contacts with something magic like Stabilant 22.
The last resort might be to pull the amp, power it up on the workbench, and tap on components and asssemblies and see if you can replicate and localize the problem.
And you've verified the grounding is OK, I think? A marginal ground could lead to some kind of feedback. Be particularly wary of crimped terminals; a lot of people don't understand how to use a crimp tool, or use a lousy one.
But it could be an internal problem. If it occurs after a mechanical shock, that points to a mechanical problem more than a purely electrical one. Possibly an unsoldered lead, or cold solder joint. If there's harnesses that plug onto boards, try replugging them, maybe treat the contacts with something magic like Stabilant 22.
The last resort might be to pull the amp, power it up on the workbench, and tap on components and asssemblies and see if you can replicate and localize the problem.
This will almost definitely be inside the amplifier, it could be a dirty switch but normally if amps make a loud crackling sound (would sound like thunder trough a sub) then it could be a one of the transistors on the input stage starting to break down, but if you say that going over bumps can make it worse, then it is likely a broken solder joint somewhere on the board
Many times, if the problem is an intermittent connection in the amp, if you tap/beat on it (with your hand), it will cause the fault to show up.
I agree that the problem could be a bad connection between the main and preamp boards. I've never heard of that fault causing the amp to rumble. It generally causes a complete loss of audio. If the connectors are causing the problem, simply separating/reseating the boards about 1/16th" a few times corrects the problem.
I agree that the problem could be a bad connection between the main and preamp boards. I've never heard of that fault causing the amp to rumble. It generally causes a complete loss of audio. If the connectors are causing the problem, simply separating/reseating the boards about 1/16th" a few times corrects the problem.
I normally find this is type of rumbling is either signal or earth related. I've never found it to be an internal issue with the amp-but then most of my customers "fit" their own gear and don't have a clue. If you've checked everything then try the "percusive maintenance" Perry suggests and see what happens.
Thanks for the responses!
I will try everything you guys suggested in order of increasing difficulty. I will try replicating the clipping by tapping on the amp. Then I will open the sub box and see what's going on in there. Last resort will be opening the amp and trying things you guys suggested above. I will start tomorrow and report back.
I will try everything you guys suggested in order of increasing difficulty. I will try replicating the clipping by tapping on the amp. Then I will open the sub box and see what's going on in there. Last resort will be opening the amp and trying things you guys suggested above. I will start tomorrow and report back.
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