Inexpensive humbucker, unpotted

Discussion in 'Just Pickups' started by Telepirate86, Feb 21, 2019.

  1. Ronkirn

    Ronkirn Doctor of Teleocity Vendor Member

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    I'm with Antigua on this one.. unless the pickup is microphonic, which is generally considered a flaw... however many actually prefer it in a Telecaster..

    r
     
  2. Zepfan

    Zepfan Poster Extraordinaire

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    I say yes and no to this.
    1. Potting will decrease the pickup's coil sensitivity to body/neck vibrations by lessening the effects of microphonics.
    2. Potting doesn't decrease sensitivity to string vibrations over the pickup's poles.

    So, Yes and No.
     
  3. Antigua Tele

    Antigua Tele Friend of Leo's

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    I've tested this http://guitarnuts2.proboards.com/thread/8739/wax-potting-experiment-capacitance-microphonics I guarantee you wax potting makes no difference in situ, unless you are into striking the pickups directly with a non-ferrous object. That's the only manner in which you can get it to produce an appreciable voltage through mechanical action alone.
     
  4. Syrinx

    Syrinx Tele-Meister

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    Obviously non potted are more sensitive or they wouldnt feedback. For me the unpotted slightly microphonic pickups offer more possibilities for tones blended with feedback.
     
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  5. Antigua Tele

    Antigua Tele Friend of Leo's

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    The only kind of feedback it yields is high pitched squealing noises, because the resonance of the tiny moving parts is of a very high frequency. Good full bodied, sustaining feedback comes from hollow or semi hollow bodied guitars, with or without potted pickups.
     
    Last edited: Jan 25, 2020
  6. rigatele

    rigatele Tele-Afflicted

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    String feedback, e.g. Hendrix style feedback, is the result of sound energy picked up through the body, conducted through the bridge and nut into the strings, and back into the pickup at resonant frequencies of the string. It has nothing to do with the pickup - the same thing happens with potted pickups.
     
  7. Zepfan

    Zepfan Poster Extraordinaire

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    We know, or should know by now, that the entire guitar will vibrate in sympathy to the string vibrations no matter what materials are used to make said guitar and that microphonics are responsible for a pickup's ability to pick up body/neck vibrations instead of just the poles getting string vibrations alone. This is why no two guitars sound the same, it's because of the materials that make up said guitars vibrate differently and add to a guitar's sound. This is basic knowledge.

    Common sense tells us that if potting/sealing a pickup reduces the microphonic effects, then the pickup's ability to covert body/neck vibrations to signal will be affected. Microphonics cannot be completely nullified, they can only be lessened in intensity.

    Therefore, if the intensity of the microphonics can be adjusted, then the pickup's sensitivity to body/neck vibrations WILL BE affected.

    Plain Physics tell us that if one part is changed - then the final result will reflect the change.
    So, potting or sealing the coil of the pickup will affect the sensitivity of the pickup to convert body/neck vibrations to signal. You do not have to strike a guitar with anything to make the pickup get body/neck vibrations and convert them to signal.
     
  8. rigatele

    rigatele Tele-Afflicted

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    The pickup is specifically designed to transform string vibrations, not coil vibrations. This is true even of an unpotted pickup. It is hundreds of times more efficient at its assigned job, than as a contact microphone. So the amplitude of the string feedback is so much greater than any coil/frame microphonic feedback, that the difference (which common sense tells us must exist) is none the less, insignificant. In engineering vernacular, it is "swamped out".
     
  9. Syrinx

    Syrinx Tele-Meister

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    When does what something was specifically designed for had any meaning to a guitar player- please- distortion anyone? I am sure neil youngs signature sound has little to do with what the pickups were originally designed for- hence the microphonics etc being a good thing- an addition to the tonal pallet.
     
  10. rigatele

    rigatele Tele-Afflicted

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    The finding of the study that was linked to, shows that the microphonic signal amplitude is tiny compared with the normal output. I think that speaks for itself, regardless of what the design intentions were.
     
  11. Antigua Tele

    Antigua Tele Friend of Leo's

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    You can't hear them though, the amplitude is simply too low. The amplitude of the microphonic content is about 1/100th of the voltage induced by the changing magnetic field. It's both below the noise floor, and completely obliterated by the primary output signal of the pickup. Even if you were to remove the bar magnet of a PAF, the remnant magnetism left over in the steel parts would still produce a greater output voltage than the microphonic quality of the pickup.

    The reason microphonic pickups ever feed back at all is under 1) high gain or very high amplitude, and 2) sympathetic vibration with a particular part in the pickup that leads to high pitched squealing sounds.

    Wax potting very much deadens a pickup to microphonics. Once the air in the coil is displaced by wax, there is no movement, there is no microphonics. In the texting I did, a wax potted pickup produced no voltage at all when struck with a non ferrous object.
     
    Last edited: Jan 26, 2020
  12. Zepfan

    Zepfan Poster Extraordinaire

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    We very much can tell a difference when it comes to 2 guitars not sounding the same, which is why we all know it to be so. We can hear the differences whether we know what they are or not, we can determine by what we're hearing that this one doesn't sound like that one. It's the microphonics that bring out those differences.

    It may not register much on a chart for you to think it's relevant, but there's a difference that many people can hear. It's easier for us to hear differences in semi-hollow and hollow body guitars because of the extra acoustic sound chambers. Solid body guitars have vibrations just like the other guitars, but the pickups have to relay them to signal, which was not the original purpose of pickups when they were designed. They were designed to only project string vibrations over the poles, but the design of the multi-wind wire coil will always have microphonics and the by-product of that will be body-neck vibrations converted to signal.

    Wax potting can and will lessen those microphonic noises that can be very irritating, but they can still come through in small amounts - including those body-neck vibrations. That's a good thing though. Who wants all the guitar's to sound the same anyway?

    I mentioned this once in one of our discussions on this subject that I had installed a set of pickups into a body without strings and tapped the poles after wiring them up to test that they were indeed working. I could also hear myself handling the body in my hands because the volume was high at the time. Many people have done that with a complete guitar and assumed that was just the strings making that noise, but it isn't just string vibrations. If those strings are removed or muted and the body and neck tapped with high guitar and amp volume, the pickups will convert that to signal without the assistance of strings. Because of potting or sealing in the pickups, this will happen at many different levels of volume. Some will be loud and some will be very quiet. I've conducted this test on many guitars over the years with different types of pickups and the sealed types have the smallest amount of sound by microphonics.
    So it can be heard at high levels of volume, but it's too low of a difference to be heard at low volume you might say; but even when signal is at low volume it can still be heard even if the one hearing it doesn't determine what it is. We sometimes need to hear it at high isolated volume to recognize what it is.
     
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  13. rigatele

    rigatele Tele-Afflicted

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    The human ear has a huge dynamic range of almost 100dB, but that range describes ratios of separate sounds. When sounds are combined, the masking effect of dominant sounds is strong. Just because you can tap a guitar or pickup, and hear something, doesn't mean that you can hear sounds that are largely synchronized in frequency and amplitude but arriving at the transducer by a different path, at greatly reduced amplitude at the same time as a much stronger signal. Concerning what people hear, the role of psychology is so powerful an influence on human perception that simple assertion and belief doesn't meet the standards that would those perceptions as facts. The only way to correct that well known and scientifically accepted deficiency, is with double blind, controlled, statistically valid listening experiments. The guitar is a sufficiently complex device that theoretical discussions can and do go on indefinitely without any real resolution. There are enough factors at play, that pretty much any theory can gain traction by engaging several of them. In other word, it is possible to develop a plausible explanation and working theory for things that are patently false. This is possible because of mis-application and/or mis-understanding of beliefs that are on the other hand, proven. However, I have seen in the past few years, that many popular beliefs about guitar electronics are simply false. I know that because carefully executed physics studies have proven them unworthy of consideration. Having seen first hand people putting up a stubborn defense of these made me even more skeptical than I was in the beginning. Thus, I don't believe anything that is synthesized by inference from a whole lot of other facts. I want to see a targeted demonstration of each individual assertion, because that is the only thing that can overcome the complexity problem I mentioned.
     
  14. Antigua Tele

    Antigua Tele Friend of Leo's

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    I never said anything remotely to the effect "can't tell a difference when it comes to 2 guitars not sounding the same", so I don't even know why you quoted me in this response you wrote.

    But I'll say this in general. If a difference is below 1dB, you won't hear it. If you have two overlapping signals and one is 100 times quieter than the other, you're not going to be able to consciously parse that quieter signal. Guitarists can make believe to their heart's content about the evils of wax potting, but there are physical and biological realities that can't be wished away. There are some guitar forums out there that soundly reject reality in favor of make believe, but I'm happy to say that TDPRI is refreshingly reality-based when it comes to matters of physics and biology. It probably owes a lot to the reverence for Bill Lawrence.
     
    Last edited: Jan 27, 2020
  15. rigatele

    rigatele Tele-Afflicted

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    To put that in perspective, that's a 40dBV difference. The ear is better at discerning tones of separate frequencies. It's not implausible that you could hear, say, a 1200 Hz tone at -40dB superimposed on a 1400 Hz tone at 0dB. The analogy is hearing someone talk at the next table at a noisy bar. However, if you now had to make out (even a phase shifted, harmonically altered) tone at the same 1400Hz -40dB, you would not be in the same situation at all. That is because the tones blend and become mostly indistinguishable. That is exactly the situation of a guitar that is presenting a tone both through Faraday induction and microphonics.
     
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  16. Zepfan

    Zepfan Poster Extraordinaire

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    Think about a dummy coil for a minute. It cancels the hum from the single coil pickup it's assigned to, how do you suppose that happens since the dummy coil doesn't have any magnetic poles?
    Coil microphonics.
    Because the dummy coil doesn't have a magnetic field of it's own, the coil does get the body/neck vibrations and sends it through the coil to the other coil it's connected to at the time to cancel hum.


    Gotta love it when one person always tells everybody else that what they're hearing isn't real and it's all in their minds because his charts say the difference is small, yet there is a difference. Not spending anymore time arguing this point.
     
  17. rigatele

    rigatele Tele-Afflicted

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    There isn't any audio transmission of hum from one pickup to another. For that to happen, one of them would have to actually emit hum as mechanical vibrations. There is no mechanism to produce that. A coil without a static magnetic field can definitely transform a changing magnetic field into an electrical current - it's the case for most coils. The static magnetic field exists in a pickup for only one reason - to magnetize the strings. External fields produce equal currents in both the pickup and dummy coil, according to Faraday's law of Induction. Because they are wired with opposite polarity, the currents cancel and then so does the hum. You can prove this by acoustically isolating the dummy coil from the body - it still works.
     
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  18. Antigua Tele

    Antigua Tele Friend of Leo's

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    Gotta love it when someone who has no earthly idea how dummy coils work, tries to school others on how dummy coils work.
     
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  19. Telepirate86

    Telepirate86 Tele-Meister

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    Jesus H....
     
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