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Newly wound pickup coil reading differently after "cooling down"

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  • Brian W.
    replied
    Originally posted by okabass View Post
    Got an idea to warm up the wire 'before' winding. Then it makes tighter coil when cooled down to normal room temperature, and you don't have to wind it so tight (breaks easier). If you warm it up to 50-60 ºC the copper wire would be approximately 1 meter longer on a single coil PU. Thats app. 0,1 mm per turn, if I calculated it right. Have to try that: you get tighter coil for "free".
    Since the summers are around 100 degrees I was thinking of putting the spool outside for awhile..........

    Leave a comment:


  • okabass
    replied
    Got an idea to warm up the wire 'before' winding. Then it makes tighter coil when cooled down to normal room temperature, and you don't have to wind it so tight (breaks easier). If you warm it up to 50-60 ºC the copper wire would be approximately 1 meter longer on a single coil PU. Thats app. 0,1 mm per turn, if I calculated it right. Have to try that: you get tighter coil for "free".

    Leave a comment:


  • mozz
    replied
    I'm not arguing i'm stating a fact. If you think or know i am wrong, please correct me. He's soldering the eyelet then measuring the resistance. After it cools it goes down. All he has to "test" is do not solder, measure, let it cool down measure.

    This is exactly how bad information gets spread across the internet. Lock the thread or delete it if i am wrong. If he or anyone wants to start a new thread on this and actually do some tests, i am more than game.

    It's the friction from the felt, your fingers, the tensioners, and stretching the wire which causes heat. My pickups go 500 ohms over, then after a while they cool down. Not soldered at all. Just insulation is scraped off.

    Leave a comment:


  • Brian W.
    replied
    [QUOTE=big_teee;n908616]The B/H is a no argument zone.
    No arguing please.

    This thread so far, is pretty much a no content thread?
    Yes, DC resistance in small wire does go up and down with temperature!
    What else?
    Thanks,
    T[/QUOTE'

    The coil also tightens up a bit after cooling down [those two items are enuff content for me!]


























    Leave a comment:


  • big_teee
    replied
    The B/H is a no argument zone.
    No arguing please.

    This thread so far, is pretty much a no content thread?
    Yes, DC resistance in small wire does go up and down with temperature!
    What else?
    Thanks,
    T

    Leave a comment:


  • mozz
    replied
    I've been military certified soldering since 1980 and never been in the military. I sand down any insulation and can guarantee you it takes less than 1 second to solder to a eyelet. Even if you held the iron on the eyelet you could not measure any resistance increase. What kind of testing you want me to do, I have about 30 pieces of test equipment.

    Leave a comment:


  • copperheadroads
    replied
    Originally posted by mozz View Post
    As soon as you are done winding the reading will be higher. Let it sit for a hour or two. I have never seen soldering for 1second to bring the reading up.
    Soldering to eyelets will usually take longer than 1 second (especially if you are using Heavy Formvar or Heavy build poly) I suggest you do some more testing .

    Leave a comment:


  • Leo_Gnardo
    replied
    Originally posted by Brian W. View Post

    Understood.
    There are plenty of occasions that the temperature & humidity on a particular day would affect the overall sound of the guitar. Cold rainy days sound one way and real hot days sound another. After living in Austin for awhile I was continually frustrated with the change in the guitars' sound from fluctuations in temperature . Of course, the amps must be taken into the equation. Hot temps seemed to sound "better" to me [fuller overall tonality, thicker tones..etc] while real cold made everything go thin and wimpy. This was also evident with acoustic guitars, too. Getting balances in the mix when in a recording studio or on a live stage became a chore.
    Let's not leave out the effects of humidity on - paper - speaker cones.

    Also, for those who play at altitudes, say Red Rocks up the hill a ways from Denver, air pressure is about 20% lower up there. Fewer molecules per cubic centimeter, foot, furlong, whatever. Speakers sound different. It affects your eardrums too. And you gotta adjust your carburetor. And boil your spaghetti longer. And breathe deeper to get the oxygen you need.

    Leave a comment:


  • big_teee
    replied
    Before we go into great length about wax potting, there are countless threads and polls here on the MEF about wax potting.
    A little research will save a lot of repeated info and posts about wax potting.
    https://music-electronics-forum.com/...obbyist/37703-
    GL,
    T

    Leave a comment:


  • Helmholtz
    replied
    Originally posted by Brian W. View Post

    Yup, I usually pot the coils. Hmm.....why .wouldn't wax potting the coil permanently preserve it in whatever
    "stretched" state it was in when the hot wax stabilized it?
    Wax/paraffin shrinks when it solidifies and thus compresses the coil. Shrinkage can be reduced by mixing bees wax (20% IIRC) into pure paraffin, but this increases the melting point by 10..15°C. And increased potting temperature might deform plastic bobbins. Also the paraffin somewhat increases the PU's capacitance depending on coil penetration depth. Not saying that it matters, though.
    Last edited by Helmholtz; 06-30-2020, 08:56 PM.

    Leave a comment:


  • Brian W.
    replied
    Originally posted by Helmholtz View Post

    Yes, temperature & humidity influence musical instruments via contraction and expansion (think truss rod tension) as well as electronics, speaker cones and probably the musician himself.
    I even noticed that the weight of my guitars drops from summer to winter by around 40g, because of lowered wood moisture content.

    But the influence on PU performance I consider negligible.
    To study the effect of a somewhat increased DCR, wire a resistor of e.g. 470R in series with the PU and see, if/how sound changes.
    I have done that and noticed a slight difference.
    I think anything that heats the pickup coil [and expanding it ] will affect the sound a little.

    Leave a comment:


  • Brian W.
    replied
    Originally posted by big_teee View Post
    Wax potting is a great stabilizer.
    Once potted the tension is no longer a factor.
    Especially recommend potting on Fender style single coils.
    Potting not only makes them less microphonic, it makes the coils more stable.
    Keep in mind if you check the DCR after taking them out of the wax pot the DCR will be sky high, until they cool off.
    I highly recommend potting pickups.
    GL,
    T
    Yup, I usually pot the coils. Hmm.....why .wouldn't wax potting the coil permanently preserve it in whatever
    "stretched" state it was in when the hot wax stabilized it?

    Leave a comment:


  • Helmholtz
    replied
    Originally posted by Brian W. View Post

    Understood.
    There are plenty of occasions that the temperature & humidity on a particular day would affect the overall sound of the guitar. Cold rainy days sound one way and real hot days sound another. After living in Austin for awhile I was continually frustrated with the change in the guitars' sound from fluctuations in temperature . Of course, the amps must be taken into the equation. Hot temps seemed to sound "better" to me [fuller overall tonality, thicker tones..etc] while real cold made everything go thin and wimpy. This was also evident with acoustic guitars, too. Getting balances in the mix when in a recording studio or on a live stage became a chore.
    Yes, temperature & humidity influence musical instruments via contraction and expansion (think truss rod tension) as well as electronics, speaker cones and probably the musician himself.
    I even noticed that the weight of my guitars drops from summer to winter by around 40g, because of lowered wood moisture content.

    But the influence on PU performance I consider negligible.
    To study the effect of a somewhat increased DCR, wire a resistor of e.g. 470R in series with the PU and see, if/how sound changes.

    Leave a comment:


  • big_teee
    replied
    Wax potting is a great stabilizer.
    Once potted the tension is no longer a factor.
    Especially recommend potting on Fender style single coils.
    Potting not only makes them less microphonic, it makes the coils more stable.
    Keep in mind if you check the DCR after taking them out of the wax pot the DCR will be sky high, until they cool off.
    I highly recommend potting pickups.
    GL,
    T

    Leave a comment:


  • Brian W.
    replied
    Originally posted by Helmholtz View Post

    It's number of turns that defines output and frequency response for a given PU design - not exact resistance. Otherwise PU sound would change with ambient temperature.
    Understood.
    There are plenty of occasions that the temperature & humidity on a particular day would affect the overall sound of the guitar. Cold rainy days sound one way and real hot days sound another. After living in Austin for awhile I was continually frustrated with the change in the guitars' sound from fluctuations in temperature . Of course, the amps must be taken into the equation. Hot temps seemed to sound "better" to me [fuller overall tonality, thicker tones..etc] while real cold made everything go thin and wimpy. This was also evident with acoustic guitars, too. Getting balances in the mix when in a recording studio or on a live stage became a chore.

    Leave a comment:

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