# How do I fix a loose input jack on my guitar amp?



## Metaguitarist (Jan 5, 2014)

I have a Line6 Spider 3 75w combo amp with a loose input jack that I need to tighten. I was messin around, loosing some screws and such but I wanted to make sure I'm not doing anything unsafe as there is a warning in the back about not opening it due to risk of shock. Do I need to be cautious about anything in particular? Obviously I'm not working on it while it is plugged in...


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## cereal_guy (Jan 6, 2014)

You'll be right


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## Daf57 (Jan 6, 2014)

The larger capacitors can hold a charge for a time even after unplugging. Altho the SS amps aren't as dangerous as the tube amps I would still be careful mucking around in there anywhere near the mains with metal implements. On some of these amps the input jack is part of the main circuit board and you may not be able to tighten. If not then you should be okay. 

I did find a couple of articles that may be of interest.
Line 6 - Support
Line 6 - Support

Be careful and good luck!


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## cereal_guy (Jan 6, 2014)

Daf57 said:


> The larger capacitors can hold a charge for a time even after unplugging.



I didn't think of that. But if you are only tightening the input jack they shouldn't be too much of a problem.


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## Krigsmjod (Jan 6, 2014)

You can unplug the amp and switch it on for a bit to drain the filter caps and then turn it off again, although I don't know what sort of time constant they'd have so that could be useless advice . Other than that don't touch anything you don't need to and tighten up the jack with a wrench and you're golden.


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## vick1000 (Jan 6, 2014)

Depends on what you mean by "tighten". If you mean the cable is loose and shorting when plugged into the jack, then you will probably need to replace the jack, unless it's an open type where you can bend the pole pieces to make better contact.

If it's just the jack wobbling around in the chassis, and it has a nut on the front, all you need to do is tighten the nut. If it's flopping around, and it's does not have a nut, then you have to resolder it to the circuit board, or replace it.


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## glpg80 (Jan 6, 2014)

Daf57 said:


> ...Altho the SS amps aren't as dangerous as the tube amps...



Not true. The rail voltages can be as high as 18+/- to 65+/-. The capacitor banks are much larger in SS amplifiers as the allowable ripple current and ripple voltage must be kept lower.

In summary SS amplifiers are even more deadly as the current discharge amount is over 20x larger compared to a tube amplifier. This is also compounded by the fact that the same safety circuits found to discharge tube amplifiers is not as common to be found in SS amplifiers. 

If anything, SS amplifiers are even more dangerous and unless you know what you're doing, should be left to a pro.


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## glpg80 (Jan 6, 2014)

vick1000 said:


> If it has a nut on the front, all you need to do is tighten the nut. If it's flopping around, and it's does not have a nut, then you have to resolder it to the circuit board, or replace it.



This is pretty much the protocol for input jack replacement. Either it is mounted to the chassis of the amplifier or it is PCB mounted.


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## Sephael (Jan 6, 2014)

Krigsmjod said:


> You can unplug the amp and switch it on for a bit to drain the filter caps and then turn it off again, although I don't know what sort of time constant they'd have so that could be useless advice


its been years since my electronics class in high school, but as i remember it that is not how capacitors work, they can hold a charge for years.


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## cereal_guy (Jan 6, 2014)

Sephael said:


> its been years since my electronics class in high school, but as i remember it that is not how capacitors work, they can hold a charge for years.



They can, unless they're discharged.


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## glpg80 (Jan 6, 2014)

Sephael said:


> its been years since my electronics class in high school, but as i remember it that is not how capacitors work, they can hold a charge for years.



+1

All of these tube amplifier myths of 1950's rectification design shortcuts are sketchy enough as is. In reality it is really amplifier to amplifier dependent for tube amplifiers alone. They especially do not apply to solid state amplifiers with modern switching supplies, voltage regulators, and current regulators with foldback circuit protection/watchdogs.


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