components coming loose?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by neufomatic, Sep 11, 2008.

  1. neufomatic

    neufomatic Member

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    Can vibrations from an amplifier being played at full volume cause solder joints to come loose? This is just a hypothetical question.
     
  2. SatelliteAmps

    SatelliteAmps Member

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    Shouldn't, unless it was poorly built.
     
  3. Trout

    Trout Member

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    Come loose? not likely, but vibrate enough to actually break a lead? Heck yes.
     
  4. SatelliteAmps

    SatelliteAmps Member

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    An amplifier should never be vibrating enough to break leads. If it did it is because of a poorly built amplifier. The components should be securely attached.
     
  5. Trout

    Trout Member

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    I guess you have not encountered it yet huh?
     
  6. donnyjaguar

    donnyjaguar Member

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    I agree with both Trout & Satellite. Having worked on vintage mobile equipment with flying leads, I assure you that vibration can break a lead. Generally its not obvious by visual inspection becase the broken lead still appears to be attached. In PCBs though this is rare enough that I don't recall seeing it myself. Even turret board gear has the components in there snug enough to get around this problem.
     
  7. phsyconoodler

    phsyconoodler Member

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    Combo amps are prone to this.If you do design the amp properly however,it should not be an issue.Not having too many flying leads,good soldering technique,and chassis mounting are all keys to preventing vibration failures.
    A wood cabinet absorbs vibrations,and some types of wood are better than others.Tolex and tweed dampen vibrations while solid hardwoods can be vibration prone.
    Many older Gibson amps had floating tubes sockets that were supposed to allieviate vibation,but they were pretty flimsy and ended up causing more problems than they solved.
    Badcat's have floating tube sockets and they cause lots of issues because the tubes fit so tight that owners often bend wiring attached to the sockets when replacing tubes.And the amps are biased so hot that tube changes are imminent.
    Old Tweed amps seemed to stand the test of time,with heat being more of an issue than vibration.
     
  8. SatelliteAmps

    SatelliteAmps Member

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    Never said I didn't see it. I said it was due to poorly built amplifiers. Most of the leads that I do see broken are broken due to stress or age, not vibration. When it is vibration related it is due to parts not being securely mounted.

    Think about how many amps sit on top of how many speaker cabinets (bass amplifiers doubly so), and how few of them just randomly break leads loose. It is a rare occurence at best for properly built amplifiers. When it does happen it is usually due to an overheating or failing part, that will cause the lead to break, rather than just vibration.

    If it is just vibration, I would love to see how it can be determined that is/was the cause.
     
  9. Trout

    Trout Member

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    The most common ones I have seen were things like screen resistors mounted directly on sockets.
    With basically minimum lead lengths involved and having seen it on more than 1 type of socket, I think it is attributed to vibration or further yet, harmonic vibrations. Yes, these were all in combo style amps. But it was never a case of poor build quality.

    Now, it is possible that the resistor leads themselves were flawed in some way, but after very careful examination of the parts, it appeared to caused by a cyclic failure (yeild strength). There was no evidence of any type of movement or flexing involved.

    I think Murphy's law applies.
     
  10. TweeDLX

    TweeDLX Member

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    Weren't the Marshall DSL PCB's prone to breakage either from overheating, or excessive vibration? Seems like I saw reviews on Harmony Central to that effect...

    Mike
     
  11. SatelliteAmps

    SatelliteAmps Member

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    Screen resistors fail primarily due to overheating or tube failure, not vibrational breakage or harmonic vibrations. If it was either of the vibrational possibilities it would happen to any of the resistors in the amp, not just the screens.

    Nor was it the type of socket they were attached to.

    If vibration was enough to do what you are saying then there would be no way to use wire to connect a speaker. It would just vibrate so much it would break. But that doesn't happen. Speakers can overheat and melt their coils, but that has nothing to do with vibrating to the point of breaking.

    Parts fail for specific reasons. If a part is not securely attached, it could theoretically shake to the point of breaking a lead, but that would be poor build quality, not bad part. (I have had that happen on some of my early builds. It was entirely my fault.) If a part over heats, it can easily self-destruct. When that happens the lead can melt or snap. Not due to vibrating, but due to overheating.

    Harmonic vibrations do not cause parts to fail.

    I don't think Murphy has anything to do with this.
     

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