Rebuild a tower speaker?

[IDBoating]

On a serious note, JL likely used a better than off the shelf component, although it still only cost them little. JL amps, along with many others, can be fixed.

If it's just a pot, opening it up will likely reveal the brand and model number and it can be removed and a new one soldered in place. Granted you need the tools and experience, but that's likely waaaaaaaaaaay less expensive than running it through the manufacturer.

If it isn't the pot, he's likely stuck sending it back anyway. I'm anxious to hear the results of his testing.

[cpropes2005]

Hopefully this weekend I will be able to get out there and give it a good maintenance wipe. lol.

[cpropes2005]

I will also get the model # off the amp. I don't know exactly when the stereo was done but my boat is an 03 so I am guessing it is pretty old.

[chpthril]

Im thinking its going to be deeper then a gain POT. He's got a 2 chnl amp with only one chnl exhibiting an issue. That 2 chnl has a single gain dial that effects the output of both chnls. Never hurts to try the cheap and easy though.

[IDBoating]

That 2 chnl has a single gain dial that effects the output of both chnls. Never hurts to try the cheap and easy though.

Ah, a dual-ganged pot. Now that I know that, I agree the two sections should "age" roughly the same so he may not get any joy from wiping. (Sorry, just had to.) But I'd still try it since it costs nothing and if he cranks it real good he might get a happy ending.

[DLafont]

Ah, a dual-ganged pot. Now that I know that, I agree the two sections should "age" roughly the same so he may not get any joy from wiping. (Sorry, just had to.) But I'd still try it since it costs nothing and if he cranks it real good he might get a happy ending.

Who doesn't like happy endings!?!

[cpropes2005]

So I got out there and gave it a good maintenance wipe today. You guys should definitely give it a try. [emoji12]

Seemed like it fixed the volume issue but still get the static and popping on the right channel with no signal. I actually unplugged the rcas all together and it was still doing it so I guess it just to has to be a bad channel on the amp.

The weird thing is I actually noticed the same issue from one of my in boat speakers that is on a different 4 channel amp. It wasn't as loud or noticeable as the tower speaker but it was definitely there. I am wondering if all of the amps are just old and starting to have issues.


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[chpthril]

If 2 amps exhibit a similar problem, that usually points to an upstream problem. But, if they still do it with no source unit connected, it could just be a coincidence.

[IDBoating]

Perhaps he should try grounding/shorting the inputs to the amps and see if the noise is generated internal to the amp.

Also, does the "static and popping" get worse while you turn the gain pot? If so, the pot is still dirty. Another free and informative test.

[cpropes2005]

No the loudness of the static and popping seems to be independent of the source unit volume or amp gains.

What do you mean by shorting the inputs to the amp?


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[IDBoating]

No the loudness of the static and popping seems to be independent of the source unit volume or amp gains.

What I meant was, Can you cause the static/popping by turning the gain pot? Reasoning: If the wiper or element are dirty, turning the pot causes the variable resistor to open/close rapidly as the wiper alternately makes and breaks contact with the element. That can cause noises that many would describe as popping or static. I've experienced failing pots that did this "just sitting there", and moving the wiper will force the issue and help confirm it.

What do you mean by shorting the inputs to the amp?

I mean connecting the input to ground.

Background: An amplifier amplifies whatever it (thinks it) sees at its input. The question here is whether the noise you're hearing is coming from outside the amp and being amplified, or from inside the amp's own circuitry. To test that, you want to remove the input signal from the amp. Disconnecting the input cable is NOT sufficient, because leaving an input "open" allows it to pick up noise from its environment. The high impedance of most amp inputs is great for normal connections (minimizes load on the upstream device) but worsens the effect when the input is left open (because high impedances are more susceptible to noise).

Each input has two terminals, signal and ground. If it's a typical "RCA" input then you can think of them as "center pin" (signal) and "outer ring" (ground). You want to short - electrically connect - the signal input terminal to ground as close to the amp as possible. Ideally, you use a standalone RCA male connector whose back end has been physically and electrically shorted and plug it into the input... this keeps the short close to the amp and minimizes the impedance of the shorting connection. A poorer way to do this would be to plug in a lengthy RCA cable and short the other end's connector; now you have inches/feet/yards of cable between the short and the amp, and all that cable length adds impedance and acts like a noise antenna.

A worst-case approach is to insert a paper clip into the amp's female RCA jack and then touch the outer ring of the jack too. Crude, and a little dangerous for the jack (don't insert the paper clip too far!), but can work in a pinch.

The basic idea is to connect the input of the amp to a good ground. Now, the amp is most definitely not getting any sort of input signal whatsoever. Anything you "hear" is thus coming from the amp itself (or, theoretically, from its power supply but good amps should have good power supply noise rejection). If you don't hear anything but slight hiss, the popping/static is upstream of the amp. If you still hear the popping and static, the problem is inside the amp itself (might still be the gain pot).

Hope this clears it up a bit. Report back on what you find!

[cpropes2005]

Wow you guys are awesome. Thanks for the detailed response, that makes a lot of sense. It might be a few days before I get around to messing with it again but I will post back when I do.


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[cpropes2005]

I tried the short test yesterday (I cut a connector off and spliced the wires together) and played with the pot and still no change. It looks like a new or rebuilt amp is in my future once I get all of my other projects sorted out.

[IDBoating]

So with the input shorted, you still have noise? Even after spinning the pot a few times and then letting it sit motionless? If so, the only thing left outside the amp is its power supply and you'd likely hear that problem repeated on all other amps including all channels of the one you're working on. I agree, sounds like a new/rebuilt amp is where you're headed. Sorry these tests weren't more successful.