Page 3 of 5 FirstFirst 12345 LastLast
Results 71 to 105 of 149

Thread: Use Multi-Section Windings to Reduce Self-Capacitance

  1. #71
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    000000000000000

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:38 AM.

  2. #72
    Senior Member
    Join Date
    Jun 2015
    Posts
    222
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Quote Originally Posted by Bagpipe View Post
    Just for the record:
    Stratitis works different, than you described it - at least according to seymore duncan.

    It has nothing to do with "string pull" and "losing pitch".

    It is slightly more complicated.
    I know a lot about Stratitus. It does impact the pitch. I wrote a post about it here Analyzing the "wolf tone" effect in a spectrogram | GuitarNutz 2

    0 Not allowed! Not allowed!

  3. #73
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    00000000000000000

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:39 AM.

  4. #74
    Senior Member
    Join Date
    Mar 2018
    Location
    Germany
    Posts
    191
    Thumbs Up/Down
    Received: 2/0
    Given: 13/0
    Quote Originally Posted by Antigua View Post
    When you turn the volume control of a 250k pot down to where there is, say, 125k ohm series resistance between the pickup and amplifier, is either the miller effect or the 150pF input C impacting the LC resonance of the guitar pickup?
    Easy to simulate. The Miller effect just shows in the increased input C. Nothing else to consider. Without the Miller effect the input C would be around 50pF.

    0 Not allowed! Not allowed!

  5. #75
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    0000000000000

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:39 AM.

  6. #76
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    0000000000000000000

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:39 AM.

  7. #77
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    0000000000000

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:39 AM.

  8. #78
    Supporting Member Steve A.'s Avatar
    Join Date
    May 2006
    Posts
    4,354
    Thumbs Up/Down
    Received: 14/0
    Given: 14/0
    Quote Originally Posted by Antigua View Post
    I recommend buying one of these so that you can see for yourself https://www.amazon.com/Gaussmeter-Fl...ds=tesla+meter
    Just wondering if you do have one of these and whether it is accurate enough to determine how much older magnets have been degaussed by time, etc.
    It is my understanding that many of the custom pickup makers will degauss humbucker magnets to specific values to capture the sound and response of vintage pickups. If that is the case would this be an appropriate gaussmeter to use?

    Thanks!

    Steve A.

    P.S. So the cheap imported strat pickups with steel pole pieces and ceramic bar magnets do not have the problem with stratitus like those with Alnico 5 pole pieces?

    0 Not allowed! Not allowed!

  9. #79
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    000000000000000

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:39 AM.

  10. #80
    Senior Member
    Join Date
    Jun 2015
    Posts
    222
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Quote Originally Posted by Bagpipe View Post
    Since this stage usually comes without gain control, Miller effect is quite an issue. In short: The higher the source impedance, the higher miller effect.
    This seems to a be a plausible cause for high end attenuation as volume is rolled off, but it raises other questions: high end loss with volume roll off is a constant problem hence the popularity of treble bleed circuits and active pickups, and yet I don't see much discussion about Miller capacitance in relation to that issue. It also appears that this is specific to the amplifier, and the situation changes if there is an effects pedal in between the guitar and the amp. You've been reluctant to expand on the issue of Miller capacitance as it applies to the objective of lowering pickup capacitance, but for these reasons, it seems the issue needs to be expanded upon.

    0 Not allowed! Not allowed!

  11. #81
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    000000000000000000000

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:40 AM.

  12. #82
    Senior Member
    Join Date
    Jun 2015
    Posts
    222
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Quote Originally Posted by Steve A. View Post
    Just wondering if you do have one of these and whether it is accurate enough to determine how much older magnets have been degaussed by time, etc.
    It is my understanding that many of the custom pickup makers will degauss humbucker magnets to specific values to capture the sound and response of vintage pickups. If that is the case would this be an appropriate gaussmeter to use?

    Thanks!

    Steve A.
    It's very good for $110. The unit of measure is millitesla instead of Gauss, so it has one less precision point than the defunct Spin Doctor model, but for guitar pickup quality control and survey, that's adequate precision.

    Quote Originally Posted by Steve A. View Post
    P.S. So the cheap imported strat pickups with steel pole pieces and ceramic bar magnets do not have the problem with stratitus like those with Alnico 5 pole pieces?
    The Gauss at the top of steel pole pieces is about 400G on center. AlNiCo 3 usually reads about 550G, AlNiCo 2 around 700, and AlNiCo 5 around 1050. The Gauss gets stronger towards the edges, so I try to get the probe dead center for consistency. "Stratitus" is usually a non issue with anything other than AlNiCo 5.

    0 Not allowed! Not allowed!

  13. #83
    Senior Member
    Join Date
    Jun 2015
    Posts
    222
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Quote Originally Posted by Bagpipe View Post
    Sorry antigua, but may i ask you a question?

    Why don't you simply type "Miller Effect" into your google and hit "GO!"? What is so difficult about it? Miller Effect is NOT complex. It is a simple relation - absolutely simple multiplication of capacitance. Sorry, but i am not used to such questions. Miller is standard.
    Am I rude to you? I don't understand why I'm getting this attitude coming back in my direction.

    I did "hit Go!" and but one example Miller capacitance being more a complicated issue than you make it out to be is presented here http://music-electronics-forum.com/t16129/

    Quote Originally Posted by Bagpipe View Post
    Consider a common emitter (or common cathode) amp. You amplify by placing a more or less high value resistor between rail and Anode(collector). So: Voltage wise, you have an amplified Version of the original present on the collector/anode. Now: Lets say amplification was 3 times. The Tube or Semiconductor has -say- 47pico BC (or GA) Capacitance. What happens with miller is, that the 47 pico is (theoretically) multiplied by 4. So you have about 200pico effective input capacitance.

    That is miller.

    Clear?
    How about we consider the case were a tube amp is not even being used by the guitarist?

    This is not an abstract issue: your claim is that when you turn down the volume controls on the guitar, the Miller capacitance goes up because the overall source impedance increases. Does this decrease the LC resonance of the guitar pickup, either in terms of frequency or amplitude?

    0 Not allowed! Not allowed!

  14. #84
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    00000000000000000000

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:40 AM.

  15. #85
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    0000000000000.

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:40 AM.

  16. #86
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    000000000000000000

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:40 AM.

  17. #87
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    0000000000000000000

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:40 AM.

  18. #88
    Old Timer
    Join Date
    May 2006
    Location
    Boston, MA area
    Posts
    2,608
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Quote Originally Posted by Mike Sulzer View Post
    I do not understand how you are so confident that the inductance does not change. Have you done this, and measured the result with an air core, or short cores as in a pickup?
    Because the geometry of the turns of the coil or coils (in the two views) is essentially unchanged. Those turns have no ide what a single-section bobbin is, or how it differs from a two-section bobbin. Imagine the turns floating in space, ignoring all the stuff that holds those turns up off the floor.

    0 Not allowed! Not allowed!

  19. #89
    Old Timer
    Join Date
    May 2006
    Location
    Boston, MA area
    Posts
    2,608
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    As for cable and amplifier input capacitance (including miller effect), the human ear is very sensitive to small changes in the spectrum of musical instruments like a guitar, so the only valid test of significance or irrelevance is a double-blind A/B listening test.

    If miller effect is a problem, use a cascode input amplifier circuit.

    Or go to low or at least lower impedance.

    0 Not allowed! Not allowed!

  20. #90
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    0000000000000000

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:40 AM.

  21. #91
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    0000000000000000000

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:41 AM.

  22. #92
    Old Timer
    Join Date
    Feb 2010
    Location
    Just south of Bawlmer, Merlin
    Posts
    2,307
    Thumbs Up/Down
    Received: 24/1
    Given: 22/0
    Shush... is he asleep? 46 posts on his first day here, insulted everyone in sight. That's got to be a record.

    0 Not allowed! Not allowed!
    Last edited by rjb; 05-21-2018 at 04:45 AM.
    Those Who Hear Not the Music Think the Dancers Mad
    - Anon (multiple citations predate Friedrich Nietzsche)

  23. #93
    Member
    Join Date
    May 2018
    Posts
    36
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Quote Originally Posted by rjb View Post
    Shush... is he asleep? 46 posts on his first day here. That's got to be a record.
    You may do dirty things to the hole at my back - but please do not make fun out of other users. I point this out a second time to users, which contributed -well- almost nothing to the thread.

    Look into the mirror, if you want to laugh about humans.

    P.S.: Nietzsche was just an overwhelming huge asshole. That is my opinion. Flush his so.called philosophy down the toilet and start reading Kant and Weishaupt. I am german. I know who i am talking about.

    0 Not allowed! Not allowed!
    Last edited by Bagpipe; 05-21-2018 at 04:16 AM.

  24. #94
    Senior Member
    Join Date
    Jun 2015
    Posts
    222
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Quote Originally Posted by Joe Gwinn View Post
    Because the geometry of the turns of the coil or coils (in the two views) is essentially unchanged. Those turns have no ide what a single-section bobbin is, or how it differs from a two-section bobbin. Imagine the turns floating in space, ignoring all the stuff that holds those turns up off the floor.
    If what you were saying was true, the inductance would have a linear relationship with the turn count, which is to say a simple multiplication, but that's not the case, it's the square of the turn count, due to flux linkage.

    0 Not allowed! Not allowed!

  25. #95
    Senior Member
    Join Date
    Jun 2015
    Posts
    222
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    The application specific implications of Miller capacitance are still not entirely clear, but that aside, I still think a low C guitar pickup is valuable for the same reason a low C guitar cable is valuable. It comes from the basic assumption that voltage is the objective, that L and C are unwanted side effects, and that to the extent they're not, you're afforded more flexibility if you add them back in, in a deliberate way.

    I've seen threads talking about lower capacitance due to thicker build magnet wire or "scatter winding", and the lowest C I've ever measured in a typical Strat pickup comes out to around 80pF at best. If a capacitance as low as 30pF can be achieved with a sectioned coil, it pretty much renders all other that other discussion moot.

    0 Not allowed! Not allowed!

  26. #96
    Supporting Member
    Join Date
    Sep 2007
    Posts
    3,000
    Thumbs Up/Down
    Received: 1/0
    Given: 0/0
    Quote Originally Posted by Joe Gwinn View Post
    Because the geometry of the turns of the coil or coils (in the two views) is essentially unchanged. Those turns have no ide what a single-section bobbin is, or how it differs from a two-section bobbin. Imagine the turns floating in space, ignoring all the stuff that holds those turns up off the floor.
    No, the geometry is different. You can look at this as two coils, each with inductance L, where the inductance of the series combination is greater than 2L but less than 4L, because they couple, and we do not know the coupling coefficient. In the single coil case you have to consider the coupling of each turn with each other turn. Of course, you can look at the split bobbin case as one coil, and then you have to consider the coupling of each turn with every other turn also. I see no reason say the two cases are the same, or different, or by how much.

    0 Not allowed! Not allowed!

  27. #97
    Supporting Member
    Join Date
    Sep 2007
    Posts
    3,000
    Thumbs Up/Down
    Received: 1/0
    Given: 0/0
    What is this big deal about the Miller effect? It just means that the input impedance of the amplifier is higher than you might expect if you did not know about it.

    0 Not allowed! Not allowed!

  28. #98
    Senior Member
    Join Date
    Mar 2018
    Location
    Germany
    Posts
    191
    Thumbs Up/Down
    Received: 2/0
    Given: 13/0
    If I had to speculate about the results of a PU coil with 2 winding sections wired in series (aka chambered coil), I would guess, that
    - total self-capacitance will be noticeably reduced
    - total inductance is reduced
    - output would be more or less the same, given the partition wall is very thin. The upper coil will contribute about twice the signal voltage of the lower one*.
    - frequency response will show one or two strong secondary resonances (anomalies).

    *@ Antigua, didn't you mention that you once wound such kind of stacked coil?

    0 Not allowed! Not allowed!
    Last edited by Helmholtz; 05-21-2018 at 05:03 PM.

  29. #99
    Supporting Member
    Join Date
    Sep 2007
    Posts
    3,000
    Thumbs Up/Down
    Received: 1/0
    Given: 0/0
    Quote Originally Posted by Helmholtz View Post
    If I had to speculate about the results of a PU coil with 2 winding sections wired in series (aka chambered coil), I would guess, that
    - total self-capacitance will be noticeably reduced
    - total inductance is reduced
    - output would be more or less the same, given the partition wall is very thin. The upper coil will contribute about twice the signal voltage of the lower one*.
    - frequency response will show one or two strong secondary resonances (anomalies).

    *@ Antigua, didn't you mention that you once wound such kind of stacked coil?
    Yes, that is what I would hope for (the decreased inductance). Thus a skilled winder could get a bit more output without losing highs. And a skilled salesman could make a big deal out it. But at least it would be based on reality, unlike a lot of other sales claims.

    0 Not allowed! Not allowed!

  30. #100
    Senior Member
    Join Date
    Mar 2018
    Location
    Germany
    Posts
    191
    Thumbs Up/Down
    Received: 2/0
    Given: 13/0
    Quote Originally Posted by Mike Sulzer View Post
    Yes, that is what I would hope for (the decreased inductance). Thus a skilled winder could get a bit more output without losing highs. And a skilled salesman could make a big deal out it. But at least it would be based on reality, unlike a lot of other sales claims.
    I thought so and see the chance as well.

    0 Not allowed! Not allowed!

  31. #101
    Senior Member ken's Avatar
    Join Date
    May 2006
    Location
    Viva Osh Vegas
    Posts
    791
    Thumbs Up/Down
    Received: 0/0
    Given: 2/0
    Quote Originally Posted by Helmholtz View Post
    If I had to speculate about the results of a PU coil with 2 winding sections wired in series (aka chambered coil), I would guess, that
    - total self-capacitance will be noticeably reduced
    - total inductance is reduced
    - output would be more or less the same, given the partition wall is very thin. The upper coil will contribute about twice the signal voltage of the lower one*.
    - frequency response will show one or two strong secondary resonances (anomalies).

    *@ Antigua, didn't you mention that you once wound such kind of stacked coil?
    I thought Duncan was famous for making this same type of stacked humbucking pickup

    Maybe somebody really needed to switch to decaf before joining forums...


    Ken

    0 Not allowed! Not allowed!

  32. #102
    Senior Member
    Join Date
    Mar 2018
    Location
    Germany
    Posts
    191
    Thumbs Up/Down
    Received: 2/0
    Given: 13/0
    Maybe somebody really needed to switch to decaf before joining forums...
    I once read about a desease called the tourette syndrome, that can't be cured by decaf.
    BTW, who cured our problem?

    0 Not allowed! Not allowed!
    Last edited by Helmholtz; 05-21-2018 at 11:47 PM.

  33. #103
    Supporting Member John_H's Avatar
    Join Date
    Jul 2006
    Location
    Las Vegas Nevada
    Posts
    958
    Thumbs Up/Down
    Received: 6/0
    Given: 2/0
    Quote Originally Posted by Helmholtz View Post
    I once read about a desease called the tourette syndrome, that can't be cured by decaf.
    BTW, who cured our problem?
    Maybe he found his meds. He was off the rails! After reading through the thread, I realized that a couple of the things being discussed with Joe's original post impacted some multi coil pickups that I'm making.

    I found a couple of good articles on the subject, and came out of it better informed. I got a good laugh when one of the articles mentioned that if you wanted to stir the pot on a message board, "start a discussion about reducing parasitic capacitance by using multiple coils".

    0 Not allowed! Not allowed!

  34. #104
    Old Timer
    Join Date
    Feb 2010
    Location
    Just south of Bawlmer, Merlin
    Posts
    2,307
    Thumbs Up/Down
    Received: 24/1
    Given: 22/0
    Quote Originally Posted by Helmholtz View Post
    BTW, who cured our problem?
    It appears that the problem self-corrected.
    But I think Warren Zevon helped.

    WZ deployed 10:58 pm; reply to WZ 11:03-11:16 pm; posts edited to "000000..." 11:31-11:41 pm.

    -rb

    PS (Edited): While we're speculating (AKA gossiping) here, fasting can screw up different people's metabolism/brain chemistry in different ways. IIRC, wasn't there some mention of Ramadan?
    Maybe fasting exacerbated a manic episode?

    0 Not allowed! Not allowed!
    Last edited by rjb; 05-22-2018 at 04:09 PM. Reason: Expanded speculative armchair psychiatry
    Those Who Hear Not the Music Think the Dancers Mad
    - Anon (multiple citations predate Friedrich Nietzsche)

  35. #105
    Senior Member
    Join Date
    Jun 2015
    Posts
    222
    Thumbs Up/Down
    Received: 0/0
    Given: 0/0
    Quote Originally Posted by Helmholtz View Post
    *@ Antigua, didn't you mention that you once wound such kind of stacked coil?
    I just compared the output levels of both halves of a stacked humbucker, which is geometrically similar Fender Vintage Noiseless, Analysis and Review | GuitarNutz 2 , the bottom coil produced about 9dBV less than the top coil. If the partition was thinner, the loss would not be as great, but I'm sure it would still be significant.

    Note that with a stacked humbucker, the lower coil is out of phase with the upper coil, so the series output of both coils is lower than the top coil by itself. The loss in that case is about 3dBV.

    0 Not allowed! Not allowed!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. multi tap windings
    By woodyc in forum Theory & Design
    Replies: 16
    Last Post: 09-04-2012, 04:15 PM
  2. Multi Section Capacitor
    By jadams in forum Music Electronics
    Replies: 3
    Last Post: 01-23-2012, 12:39 AM
  3. Implications of multi AC in windings...
    By trevorus in forum Maintenance, Troubleshooting & Repair
    Replies: 2
    Last Post: 05-03-2010, 02:31 AM
  4. Multi-section caps last longer?
    By Axtman in forum Maintenance, Troubleshooting & Repair
    Replies: 11
    Last Post: 09-17-2009, 10:09 PM
  5. Multi-section Cap Question
    By Direwolf in forum Build Your Amp
    Replies: 2
    Last Post: 11-06-2006, 05:49 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •