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  1. #1

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    I have an old adapter cable that allows you to use a regular guitar cord with a screw-on De’Armond pickup. There is what looks like a capacitor and resistor inside the female connector. Does anyone know what the purpose of these extra components would be? It doesn’t seem to affect the sound when I compare it to a simple screw-on cable. I attached a picture.
    thanks,
    Keith
    Question about electronics - De’Armond adapter cable-ac1288be-3c24-458b-8a37-6da5f4f5e18e-jpg

  2.  

    The Jazz Guitar Chord Dictionary
     
  3. #2

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    Probably intended to act like a treble bleed circuit to manage loss of highs due to capacitance in the extra cable. How much of a difference that's actually going to make, compared to having that circuit on the volume pot, it is unclear to me.

  4. #3
    In basic electronics the combination of a capacitor and resistor make a filter. The type of filter and the frequencies affected are determined by the order of the components and their values.

    I would say it is some type of fixed tone control so a bleed control as mentioned would make sense.

    Sent from my LM-V600 using Tapatalk

  5. #4

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    A treble bleed circuit has the resistor and capacitor wired in parallel. This one is series wired, just a band-pass filter.

  6. #5

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    Quote Originally Posted by Cunamara
    Probably intended to act like a treble bleed circuit to manage loss of highs due to capacitance in the extra cable. How much of a difference that's actually going to make, compared to having that circuit on the volume pot, it is unclear to me.
    I guess that’s what someone was trying to accomplish. If the idea was to maintain the treble, that doesn’t seem like something I really want in my signal. I would rather have something that reduces the treble a bit, so it would warm up an old guitar mic that doesn’t have a tone control.
    Keith

  7. #6

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    Quote Originally Posted by sgosnell
    A treble bleed circuit has the resistor and capacitor wired in parallel. This one is series wired, just a band-pass filter.
    What does a band-pass filter do?
    Keith

  8. #7

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    It filters out frequencies, and allows a selected band to pass. The exact band depends on the values of the resistor and capacitor. Band-pass filter - Wikipedia

  9. #8

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    I would think that the circuit shown would result in less high-frequency going to the amp as it goes from hot to ground.

  10. #9

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    This is not a band-pass filter.

    It is a low-pass filter.

    The .01uf cap is smaller than the .022uf most often used in passive tone controls - which are low-pass filters.

    The resistor color bands are very hard to accurately see in the pic.

    If the bands are brown/black/brown, the resistor is 100 ohms which is an extremely low value for the high impedance of a passive PU.

    This would roll off the highs quite a bit. But to many jazz player ears be possibly quite pleasing.

    If the resistor were colored yellow/violet/yellow this would be 470K ohms. This circuit would then do very little, except filter out the most extreme scratchy high frequencies in the attack.

    The OP can possibly tell us the colors as seen in-person. The reported limited effect is consistent with 470K ohms.

    Off topic:

    The Z5U on the ceramic cap refers to the specification for the cap. A Z5U cap is designed to be inexpensive and relatively small in size, with a remarkably wide tolerance and relatively narrow operating temp range.

    Pretty funny to have people hear differences in cap technologies, when they are really hearing differences in cap values. The often used Z5U caps most typically have a tolerance range of +80% to -20%.

    You can hear an 80% difference in cap value. You can not hear paper in oil.

  11. #10

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    Since it came up:

    A so-called ‘treble-bleed’ is a high-pass filter.

    The simplest of these would be a single cap, which as you lower the volume pot (assuming it is wired as a true potentiometer, with the output on the center wiper) results in the cap being in parallel with the segment of the pot resistance that is now in series with the signal “hot” path.

    The cap allows high frequencies to bypass this segment of the pot resistance.

    A treble bleed can also have resistors in series with the cap. By adjusting the values of the cap and the in-series resistor, you can adjust the shape and depth of the bypass/bleed response curve. In principle, the resistor in series with the cap would adjust only the extent of the bypass. In practice it will alter the curve shape as well.

    BUT, you can also have a resistor in parallel with the treble bleed cap.

    Or resistors both in series and in parallel with the bleed cap.

    The resistor in parallel with the bleed cap alters both the depth and shape of the cap bleed curve, and the practical taper of the pot.

    There is an amazing amount of control available in our pathetically high-impedance, remarkably sloppy guitar circuits.

  12. #11

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    Here is a fun description of a treble bleed from an expert source:

    Apparently “series” is the new parallel.

    Mojo Tone Volume Mod for Guitars | Sweetwater

  13. #12

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    And by far, the best of the best:

    Fender “Integrated Circuit” capacitors.

    Now there is no such thing.

    There is, oddly enough a company called “Illinois Capacitor”. Hmmmmm...

    Here is a wonderful description of a non-existent (yet with known “musicality”) technology:

    Fender Guitar Upgrade Capacitor 0.02MFD 50V IC | Guitar Center

  14. #13

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    PSA: Lots of guitarists have issues with ED—“Electromagnetic Dysfunction”. The wiring’s there, but the pickup doesn’t work the way it should, and output is sporadic. Even if you get a decent signal, you feel frustrated that you can’t push it into overdrive.

    Many guitarists have been known to give up completely and take up the banjo, leading to solitary lives of bitterness and regret.

    I think a little blue cap will solve your impedance problem. Call 1-800-BLUECAP for more information.

  15. #14

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    Quote Originally Posted by Bezoeker
    This is not a band-pass filter.

    It is a low-pass filter.

    The .01uf cap is smaller than the .022uf most often used in passive tone controls - which are low-pass filters.

    The resistor color bands are very hard to accurately see in the pic.

    If the bands are brown/black/brown, the resistor is 100 ohms which is an extremely low value for the high impedance of a passive PU.

    This would roll off the highs quite a bit. But to many jazz player ears be possibly quite pleasing.

    If the resistor were colored yellow/violet/yellow this would be 470K ohms. This circuit would then do very little, except filter out the most extreme scratchy high frequencies in the attack.

    The OP can possibly tell us the colors as seen in-person. The reported limited effect is consistent with 470K ohms.

    Off topic:

    The Z5U on the ceramic cap refers to the specification for the cap. A Z5U cap is designed to be inexpensive and relatively small in size, with a remarkably wide tolerance and relatively narrow operating temp range.

    Pretty funny to have people hear differences in cap technologies, when they are really hearing differences in cap values. The often used Z5U caps most typically have a tolerance range of +80% to -20%.

    You can hear an 80% difference in cap value. You can not hear paper in oil.
    Thanks Bezoeker for the detailed explanation. The color bands on the resistor look like yellow/violet/yellow to me. That is consistent with your description of a circuit that does very little, which is what my ears are telling me too. Thanks so much!
    Keith
    Question about electronics - De’Armond adapter cable-27ada31b-6507-409c-a6be-5f99b15f868c-jpeg

  16. #15

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    Quote Originally Posted by floatingpickup
    Thanks Bezoeker for the detailed explanation. The color bands on the resistor look like yellow/violet/yellow to me. That is consistent with your description of a circuit that does very little, which is what my ears are telling me too. Thanks so much!
    Keith
    Question about electronics - De’Armond adapter cable-27ada31b-6507-409c-a6be-5f99b15f868c-jpeg
    Great pic Keith. I was confused by the earlier one.

    So this makes 100% sense in all ways.

    Which is nice. Thanks.

    EDIT: The gold band on the resistor is for tolerance, not value.
    Last edited by Bezoeker; 02-28-2021 at 11:19 AM.

  17. #16

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    It is my thought that it is there to shunt very high frequency noise or spikes to ground, like from dimmer, florescent lights or a nearby radio transmitter. Little or no effect on sound that you hear.