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Guitar cable capacitance -- how much is too much?

Discussion in 'Amp Tech Center' started by King Fan, Jul 25, 2020.

  1. TeleTucson

    TeleTucson Tele-Afflicted

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    Some of us are just curious and want to understand the root causes, and certainly the iconic pickup innovators back in the day made design choices based on understanding how all these factors translate into sound.

    But - to your point - of course we should all ultimately make choices based upon sound.
     
    Last edited: Jul 26, 2020
  2. guitararmy

    guitararmy TDPRI Member

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    I find this very interesting! So the cable is a big part of the sound that guitarists got playing live.
     
  3. 3-Chord-Genius

    3-Chord-Genius Poster Extraordinaire

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    Side note: in all the interviews I've seen or read of famous guitarists, none of those guys mentioned anything about cable capacitance, scatterwound pickups, fretboard radius, or any of the other stuff that we obsess over. It's like there are two classes of guitar players: 1) hobbyists who have a fetish for technical minutiae, and 2) musicians who write and play great songs and are successful at it.

    It's likely because if any of these things actually matter, the true musicians simply move their guitar or amp tone knobs a little bit to get the sound they desire - then they make music.
     
  4. Matthias

    Matthias Friend of Leo's Gold Supporter

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    I have a long cable that I presume has quite high capacitance. My Thinline sounds pretty good through it as it's tamed a little. I like it!
     
  5. Tark1

    Tark1 TDPRI Member

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    Yes it is possible to calculate the effect of cable capacitance. Bear in mind that the way the cable interacts with the guitar circuit and pickup does vary depending on the position of the controls. Most pickups have a self capacitance of between 100 to 200pF and with no added capacitance will self resonate in the 5 to 6kHz range. So your total cable capacitance would have to be very low indeed - 10 to 20pF - to have an insignificant effect.
    With your 540pF cable your guitar response is probably peaking around 3.5kHz and rolling off at 12dB per octave thereafter. That's assuming all guitar controls are at maximum.
     
  6. Left Coast

    Left Coast TDPRI Member

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    Hello all,

    Cable capacitance is all well and good but honestly, it is such a small factor in the signal chain. Keep in mind that it does not make a noticeable difference if using pedals (buffered or not), because all pedals act as buffers when on and will negate the capacitance in the cable. Plugging directly into an amp? Now you can hear a difference. But whether or not YOU can here a difference varies depending on YOUR equipment (guitar, amp, and even strings are all contributing factors).


    Tonal arguments aside I would spend extra money on a good cable because it is more DURABLE and reliable that a mass produced cable, other factors such as shielding should also be considered. Attention to detail is what will win my money.

    Hope that helps...
     
    Last edited: Jul 29, 2020
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  7. Lowerleftcoast

    Lowerleftcoast Friend of Leo's

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    Devils advocate:
    I have never read of Bonamassa talking of such things but he has admitted to owning 400 guitars and 400 amplifiers. I doubt he simply moves the guitar or amp tone knobs a little bit to get the sound he desires.

    It is said SRV requested a Radio Shack curly cord. (He owned a few guitars and amplifiers as well.)

    Scatterwound pickups = almost any pickup ever wound.

    2) musicians who write and play great songs and are successful at it.
    Did you mean financially successful at it? Ha! I doubt it.

    Musicians who write and play great songs and are financially successful at it, buy amplifiers from hobbyists who have a fetish for technical minutiae, such as Howard Dumble.

    This devils advocate can't think of a fretboard radius quote to counter your observation. Tadeo Gomez must have been a do'er not a talker.

    :lol::lol::lol:
     
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  8. bob palmieri

    bob palmieri TDPRI Member

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    Keep in mind that the effect of cable capacitance is very different depending on the guitar's volume control setting (assuming a conventional passive control harness.) With the volume on 10, the cable capacitance will move the resonant frequency down. On any other string, it just rolls off high end.

    Regarding Jimi, not only did he tend to use the high capacitance cable in live situations but also plugged it into a Cry Baby at the other end. These things have a shockingly low input impedance in their stock configurations, and will roll off high end and lower the level of the now-lower-in-frequency resonant peak.

    Incidentally, some of the pickups I make are wideband passive mags for specific applications, and I can't get them into spec without very low capacitance cable, which I source from a local supplier called Best-Tronics. One of my customers, Ken Parker, who uses these pickups on his high end bronze-strung arcbtops, supplies one of these cables with the guitars.

    Bob Palmieri
    Duneland Labs
     
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  9. tubegeek

    tubegeek Friend of Leo's

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    As a vendor there are specific rules which apply to you. You might want to read them.

    https://www.tdpri.com/threads/commercial-rules-for-this-website.616710/

    (I have no intention of reporting your post and I am not a mod. Just a goody-two-shoes pain in the ass.)

    Welcome!

    @bob palmieri same.
     
    Last edited: Jul 29, 2020
  10. kennl

    kennl Tele-Afflicted

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    4 things to consider when selecting a cable

    Noise (rf)
    Noise (microphonics)
    Ergonomics
    Tone

    I have some 1970’s vintage Bill Lawrence cables that have the best shielding of any cable I’ve found and no high-end rolloff. They are stiff, will not lay flat, and are almost unusable onstage.
    I have Spectraflex “woven jacket” cables that are rugged, lay neatly onstage and roll off some high end. If you wiggle the cable, you will hear handling noise through the amp.
    I also have cheap curly cords that are noisy (poor shielding), have OK tone and are very convenient onstage. Not a tripping hazard, and unlikely to destroy an output jack if yanked.
    I have numerous other cables with moderate issues, like a Lava coil cord that weighs more than some of my guitars.

    Strictly considering tone, a high-capacitance cable can be effective at taming some high end. But if it’s a single coil passive guitar and your cable is poorly shielded, the result might be ugly.
     
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  11. Left Coast

    Left Coast TDPRI Member

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    I appreciate you pointing that out and I have edited the post to comply! ;)

    PS. that was not a cheeky attempt at marketing!
     
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  12. chris m.

    chris m. Poster Extraordinaire

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    For folks thinking this is too esoteric and cork sniffing, get your cords out and experiment. It can be an eye/ear opener to hear the big difference in tone between a 3’ cord plugged straight into your amp and a 20’ cord. Yes, in addition to capacitance shielding, flexibility, and durability matter. Price matters, too. My practical solution has been a 10’ Spectraflex cable from guitar to pedalboard and my first pedal being a buffered pedal. By the way, some true bypass aficionados who don’t like what a buffered pedal does to their signal may actually be hearing higher frequencies being restored. Also, many folks who say plugging straight into an amp always sounds better than pedals may again be hearing the impact of altered capacitance in one direction or another depending on whether any of the pedals are buffered. If all true bypass then plugging straight in reduces capacitance. If they have a buffered pedal then eliminating the pedalboard may increase overall capacitance.

    Another reality is the buffer itself shapes tone a bit. I personally think the Boss pedal buffer sounds fine, and better than no buffer, as long as there are only up to about 3 Boss pedals. More than that and I hear the tone shift from stacked buffers.
     
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  13. King Fan

    King Fan Poster Extraordinaire Ad Free Member

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    Thanks all. I almost feel guilty triggering such a smart discussion with my dumb question. But I'll get over it. :)

    Several posts have touched on cable movement, microphonics, and tribolelectric noise (cool new word!). I see now many high-end (Canare, Mogami, etc.) cables are designed to minimize this. Word to the wise -- both those companies have a little callout box on the bottom of their pages saying something like this.

    upload_2020-7-29_7-55-40.png

    That inner shield is subtle, but wrapped around the clear plastic shield, its also pretty fat and prone to melt, so readily makes contact with solder/wire/lug. I'm not big on reading to the bottom of spec sheets, so I found out the hard way (talk about rolled-off signal) -- strip the inner black jacket back away from the sleeve connection, leaving just the plastic core insulation in that area.

    Finally, I read that not only pedals (all pedals? that's interesting) but also active onboard electronics in your guitar make cable capacitance moot.
     
    Last edited: Jul 29, 2020
  14. Left Coast

    Left Coast TDPRI Member

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    That inner shield is very thin and is conductive. If it comes into contact with the conductor it will "short" the cable out-but I guess you found that out! Most raw cables use it.

    You are correct in that active electronics and the use of pedals negates the cable issue. Unless the pedals are true bypass and are off-then the jumpers and all the cable on the pedal board adds to the capacitance.
     
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  15. JazzDreams

    JazzDreams Tele-Meister

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    9 and 11 MHZ would be RF (radio) frequencies in the middle of the HF spectrum. I'd try again...
     
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  16. billstyler

    billstyler TDPRI Member

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    Options to consider:
    https://www.wildepickups.com/products/cable-plugs-set
    https://www.wildepickups.com/products/filter
     
  17. tubegeek

    tubegeek Friend of Leo's

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    I spent several years teaching an electronics lab and the very first day we started with a 1/4" TS - 1/4" TS cable as their intro to soldering.

    There are a LOT of details! And each of them are important in terms of performance and longevity. I'm not always impressed with the workmanship I see when I open a connector.

    By the time we got to XLR's they were doing much better work, and most of them were able to build a 1/8" TRS - 2x1/4" TS by the time I was through with them. THAT'S a hard job!
     
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  18. larsjm

    larsjm TDPRI Member

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    The most important question of course is what color are your pickup cavities? A conductive offset will negate the high frequency interaction, whilst enhancing long-term parasitic propagation. Simple transconductive splicing will neutralize the emission of unwanted sinusoidal cancellation. As long as the corner frequency of your offset is aligned with a fundamental tone, your overall phase modulation should be null.
     
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  19. gregulator450

    gregulator450 Friend of Leo's Silver Supporter

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    I calibrated my ear drums by going to a lot of concerts and playing a lot of drums without using ear plugs.
     
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  20. tubegeek

    tubegeek Friend of Leo's

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    It depends a lot on the orientation of the annulated fram.

    EDIT: my mistake, it's the panametric fam whose orientation is critical. See video below.
     
    Last edited: Jul 29, 2020
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