Troubleshooting Amp Rattle

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lukedlblukedlb Frets: 488
Further to a previous thread where I searched in vain for the source of a rattle in a combo, and before I start my quest again from scratch, I thought a specific thread of a troubleshooting checklist could help us all out.
As ideas and tips are suggested, I will try to compile a final checklist with a progressive list of items to check for. Let's see how it goes for now and I'll try my best to incorporate everybody's suggestions.
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  • lukedlblukedlb Frets: 488
    Identifying the source:

    amp head

    or

    speaker cabinet

    or

    combo
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  • Modulus_AmpsModulus_Amps Frets: 2569
    tFB Trader
    Always fully isolate the electronics from the speaker first, be it a head or combo etc

    some buzzes are obvious though
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  • lukedlblukedlb Frets: 488
    Speaker cabinet:

    The loudspeaker: dust/rust in speaker coil. Tears on speaker cone. Speaker cone touching baffle. Missing washers or grommits magnetized to speaker chassis or bouncing inside or underneath the cone.
    The baffle: speaker not screwed tightly to baffle. Extra grommets hiding between baffle and grill cloth. Baffle not properly screwed onto cabinet.
    The cabinet: screws need tightening. Missing screws and grommets hiding inside the cabinet or between wood. Tolex torn or unglued touching other elements of the cab.
    Accessories: handles require tightening. Handle metal plates not on tight enough. Logo vibrating against cab. Cab corner guards need screwing down. Wheel housing is not tight against cab. One wheel isn't touching the ground.
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  • lukedlblukedlb Frets: 488
    That should start off the thread. It's the combo where things get difficult due to the amplified vibrations impacting upon the amp chassis.
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  • Just a suggestion, get someone else to play the note(s) that cause the rattle while you get up close and personal with your ears to narrow down the section on the cab that is rattling ie. left side, right side , top, bottom. Ears are pretty good at locating noise sources. Plus you will have both hands free to prod and poke. Don't prod and poke the electrics though !!!
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  • lukedlblukedlb Frets: 488
    Max_b3 said:
    Just a suggestion, get someone else to play the note(s) that cause the rattle while you get up close and personal with your ears to narrow down the section on the cab that is rattling ie. left side, right side , top, bottom. Ears are pretty good at locating noise sources. Plus you will have both hands free to prod and poke. Don't prod and poke the electrics though !!!
    I have a looper as my assistant. Above, ears suggest it's in the middle third of the amp. From behind, ears have no idea. Even from the front. Hence the list to go through as insanity takes over.
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  • lukedlblukedlb Frets: 488

    Always fully isolate the electronics from the speaker first, be it a head or combo etc

    some buzzes are obvious though
    Yes, treating the amp and cab as two separate entities is the first step, without the amp head sitting on the cab. This will identify issues commonly found in combos, where the vibrations are setting off mechanical disturbances that might impact on the electronics.
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  • Luke, interesting thread...ill keep my eye on this 
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  • lukedlblukedlb Frets: 488
    Speaker cabinet: poor speaker wire connection due to frayed ends, poor quality solder or lack thereof. (thanks @Essbie )
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  • p90foolp90fool Frets: 31367
    Submerge it in water and see where the bubbles come out when you play, bicycle inner tube style?
















    (No don't, really)  :)
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  • Annoying rattle on my Pro Junior at high volume traced to the metal Fender plate on the back panel.  I slid a bit of card between it and the panel - job's a good 'un!

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  • lukedlblukedlb Frets: 488

    Annoying rattle on my Pro Junior at high volume traced to the metal Fender plate on the back panel.  I slid a bit of card between it and the panel - job's a good 'un!

    I did the same with a control panel that wasn’t flush against the chassis, eventually substituting the card with felt. 
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  • lukedlblukedlb Frets: 488
    Always fully isolate the electronics from the speaker first, be it a head or combo etc

    some buzzes are obvious though
    Amp put on a stool connected to the combo cabinet. Fortunately, it isn't a speaker problem. The throaty rattle was no longer present. However, the gold metal grill on top of the cab vibrated, albeit at a different frequency. The wood is thin so I won't use a staple gun (mine is a big one which will punch through the wood). A friend suggested v-shaped nails. Any thoughts? I did hammer in the remaining staples when I went over the cab last. Clearly, the vibrations were enough to loosen them again. It'll probably just take one.
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  • ICBMICBM Frets: 71951
    lukedlb said:

    Amp put on a stool connected to the combo cabinet. Fortunately, it isn't a speaker problem. The throaty rattle was no longer present. However, the gold metal grill on top of the cab vibrated, albeit at a different frequency. The wood is thin so I won't use a staple gun (mine is a big one which will punch through the wood). A friend suggested v-shaped nails. Any thoughts? I did hammer in the remaining staples when I went over the cab last. Clearly, the vibrations were enough to loosen them again. It'll probably just take one.
    Use hot-melt glue. Inject it through the mesh with the cabinet upside down.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • There's a ceramic base to a valve holder, and the valve pins fit into tiny metal sleeves in the base. Some of those are unused and they seem loose, presumably these will or could rattle. Or is that a dead end?
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  • p90foolp90fool Frets: 31367
    There's a ceramic base to a valve holder, and the valve pins fit into tiny metal sleeves in the base. Some of those are unused and they seem loose, presumably these will or could rattle. Or is that a dead end?
    It is possible I guess, but they're so light I'd be amazed if their rattling was audible. 
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  • ICBMICBM Frets: 71951
    There's a ceramic base to a valve holder, and the valve pins fit into tiny metal sleeves in the base. Some of those are unused and they seem loose, presumably these will or could rattle. Or is that a dead end?
    None of the pins are unused in a Marshall with EL34s, unless it's a mid-70s one without screen resistors, in which case it should have them fitted for valve reliability reasons alone - pin 6 is then used as the support for the other end of the resistor.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • Bygone_TonesBygone_Tones Frets: 1527
    edited December 2019
    With a rattling noise you should always get the speakers out and check them over properly. In my experience, the most common problem on old Celestion speakers is the glue at the spider support failing, and coil rub. Either of these problems will cause rattling if the problem is severe enough.

    Spider Support - To check the spider support you want to brush your finger tip against the edge, all the way around, and see if it lifts off anywhere. Be as thorough as you can. Severe example shown in the photo below, but even just a small area of failed glue will affect the sound of the speaker.  VERY common on old Celestions, I cant stress this enough to people. Especially with the prices some people are asking for them thesedays. Imagine paying over a grand for a pair of vox blues and finding the spider supports are like the photo below. Personally I would be livid. Always check. Repairing this is not as straight forward as just glueing it back down. The voice coil would need to be re-centered, and you will need to clean the coil gap of debris.



    Coil Rub - The correct way to check for coil rub (in my opinion) is to press lightly around the outer edge of the speaker cone. If you check in 8 different positions it should be thorough enough (see pic below). Also check the outward cone movement by lifting the cone from underneath.



    Most people check for coil rub just by pressing directly down on the cone.  This is not good enough in my opinion. I've had quite a lot of coil rubbing speakers here that have passed that test. Pressing around the outer edge is more thorough.

    I've got some videos of these tests on my website, and a more indepth speaker testing article:


    The vids are not very good quality admittedly, I will try and upload some better ones next year. 
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  • ICBMICBM Frets: 71951

    Spider Support - To check the spider support you want to brush your finger tip against the edge, all the way around, and see if it lifts off anywhere. Be as thorough as you can. Severe example shown in the photo below, but even just a small area of failed glue will affect the sound of the speaker.  VERY common on old Celestions, I cant stress this enough to people. Especially with the prices some people are asking for them thesedays. Imagine paying over a grand for a pair of vox blues and finding the spider supports are like the photo below. Personally I would be livid. Always check. Repairing this is not as straight forward as just glueing it back down. The voice coil would need to be re-centered, and you will need to clean the coil gap of debris.
    I know exactly where there is a pair of Vox Blues precisely matching that description. They're out of a '63 AC30 that was stored somewhere slightly damp for about 30 years and the frames have rusted enough to dislodge the paint and thus the glue most of the way round on both speakers. They're included with the sale of the amp - it currently has a pair of 70s G12S-20s in it, which actually sound very good - if a future buyer wants to have a go at repairing them, since it's beyond my skills and tools.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • lukedlblukedlb Frets: 488
     After a long journey, the source of the rattle in my amp was identified as a microphonic power tube brought on my cabinet vibration. Which brings me to the next element in this thread:

    the amp:
    Power tubes
    Pre-amp tubes
    valve base has loose teeth
    loose or missing screws

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