Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com

Truth in Capacitors

Discussion in 'Tele-Technical' started by Kirfew, Apr 12, 2012.

  1. slippin slider

    slippin slider Tele-Afflicted

    Jul 30, 2013
    California
    Just last night, I was compiling a list of parts for Marauder-caster, and thought capacitors, huh?
    So startedx googling capacitors and ran into bumble bee capacitors. Yikes! They are really expencive.
    So I read and read some more. The thing that I learned was I don't pooh about eletricy and two, the advice
    The advice I understood : all that matters is can you hear the differance or not.
    When buying bumbble bee capacitors that your thingy and test each one, because .22 is a good one and one that reads .33 will be to dark for humbuckers. :rolleyes: what?...:oops:'
    Sorry all that I can remember is the number from the example noti how to write it down in the proper manor.

    The image of the wonderfully gothic grave is beautiful +3.

    Speaking of the old guys telling others what to do, what is true and what is not. well.......
    That might help in understanding the high devorce stats in this country.
     

  2. Rob DiStefano

    Rob DiStefano Poster Extraordinaire Vendor Member

    Age:
    71
    Mar 3, 2003
    NJ via TX
    what dialect of english are you speaking that i don't understand?
     

  3. slippin slider

    slippin slider Tele-Afflicted

    Jul 30, 2013
    California
    Rob
    I appologise for speaking dyslectic/chemo-brain.
    I am dyslexic and then had a regiment of very intense chemo and radiation
    You are reading dyslexic/-short term memory -concentration .
    It's a tough language to wrap ones head around.

    I will try again: I learned that I don't know any thing about electronics
    I was impressed by how much there is to learn before adding a capacitor to a guitars circuit
    Better?..
     

  4. Geo

    Geo Friend of Leo's

    Age:
    68
    Mar 17, 2003
    Hendersonville, TN
    I bought a capacitance meter for $15 today so I don't have to guess based
    on the the tone pot sweep with type pickups or get a magnifying glass and
    a cap ID decoder for some of the mini micro ones that don't have the actual
    uf rating printed on.
    All in all it is mainly for Tele bridge pickups as am slowly disconnecting
    the neck pickups from the tone pot.
     

  5. Rob DiStefano

    Rob DiStefano Poster Extraordinaire Vendor Member

    Age:
    71
    Mar 3, 2003
    NJ via TX
    thank you. all that matters with caps is what yer ears tell ya - then spec out the caps so you'll know for future reference. any cap will do, foolish to waste money on expensive ones.
     

  6. Rob DiStefano

    Rob DiStefano Poster Extraordinaire Vendor Member

    Age:
    71
    Mar 3, 2003
    NJ via TX
    if yer tone pot is of decent build (cts, alpha, etc), open it up and make it into a no-load, then all yer pups will be free from that tone sucking cap. :cool:
     

  7. Geo

    Geo Friend of Leo's

    Age:
    68
    Mar 17, 2003
    Hendersonville, TN
    Actually Rob I'm doing this as mainly use neck pickup with tone up all the way
    but bridge with tone rolled back a bit. So whenever I go from one to other
    have to turn tone up or down and then reverse again to other pickup. This way
    can set the bridge tone dedicated and not have to change the tone control
    when going to neck or neck + bridge. It also makes the neck pickup sound
    tad bit more full. Actually one Tele I did this on has a no load pot but
    just wanted to eliminate that up down on the toner knob. I set the amp to
    sound wanted on neck then as always end up backing off tone bit for bridge
    to sound wanted but still can adjust bridge tone brighter if needed.
     

  8. jefrs

    jefrs Doctor of Teleocity

    Nov 20, 2007
    Newbury, England
    Is this thread still alive?

    It has lasted longer than many pio capacitors ;)



    My bete noires are ceramic capacitors. The insulation is fired clay 'biscuit', it is porous and can absorb moisture and grease, and bits can fall off. They are actually usable. I will use them where it doesn't really matter what the value is, nor if it remains stable.
     

  9. chris m.

    chris m. Friend of Leo's

    It's funny- when you mention it, there is a need to tweak the tone knob as you switch pickups on a Tele since it has a master tone. Yet tweaking the volume and tone knobs is so instinctive for me that I don't think about it or even notice it. The converse is when an acoustic player uses an electric and has no clue about the knobs, or the type of player who prefers to control everything using pedals.
    I'm also convinced that a lot of guys who constantly are on a pickup quest suffer from wanting them to sound perfectly balanced without having to do any fine adjusting with either pot. At a certain point just get an Esquire!
     

  10. jefrs

    jefrs Doctor of Teleocity

    Nov 20, 2007
    Newbury, England
    With a tone pot at 10 then the capacitor is effectively out of circuit. The roll-off is then up at several kHz in the ultra sound if not the rf region. General formula is F = 1/(2piCR)

    Do not forget that the pickup is also an inductor coil, we have an LCR circuit.

    You can measure the response of the control. There are frequency analysers for PC, simple audio oscilloscopes too. Just jack your guitar into the computer by whatever means. An 'app' like SPLnFFT probably would do it, I haven't tried yet.

    For me the no-load has no benefit other than an embarrassing pop! as it is engaged.
     

  11. Davo17

    Davo17 Friend of Leo's

    Thanks you are always good for some tele tips. What values do you tend to use and why? I know you have a Baja.

    I picked up a selection of caps on ebay, and have been experimenting-the latest discovery is how the cap value impacts the frequency of the tone pot.
    I used to wonder how people played with the tone control all the way back (or most of the way off), however with the right value and amp it can sound pretty good.
     

  12. jefrs

    jefrs Doctor of Teleocity

    Nov 20, 2007
    Newbury, England
    ^^^ I use both tone and volume controls.

    The volume I setup at about 50% i.e. 125:125 [kohm]. That is '5' on a linear, I use a linear but most do not, I need more coffee to think what it is on a log pot.
    The tone I generally have rolled off a little to take the edge off, at 10 or down around 1-2. It all depends what I want to do.

    Typical tele, single-coils, 250k vol plus 250kLOG+47nF. The tone pot is always logarithmic (unless jazzmaster weird system ;)

    I have done the experiment with values, and with different types.
    5nF = 0.005µF, 10, 22, 33, 47, 100nF note the semi-logarithmic series.
    The type makes not one jot of difference, three parts of bugger-all, the value is absolutely everything.

    But what happens if you plot the response is we find the same roll-off is available at a slightly different point on the pot. You can hear/feel a slight difference between a 20nF and a 25nF, they're at different points. So choose the capacitor for how you use the tone control.

    Why does this feel important? The Log pot is badly logarithmic, it consists of four linear tracks laid end to end. There are steps in it and we 'feel' the jump with our ears and fingers, but nobody other than the player will notice. A linear pot has no steps but is utterly useless for a tone control, it puts everything it does into one end.

    Get a capacitance meter, often a DVMM function.

    Some types have properties that makes them especially suited to certain applications, notably at radio frquencies and VHF, but not at audio. There's nothing to chose between them at audio.

    However the reason for not choosing PIO or ceramic for the guitar tone control is because they are not stable and tend to fall apart disastrously.
    Similarly the reason for choosing a high voltage capacitor for the guitar is (a) they come like that (b) they have thicker, stronger wires.

    Why spend a lot of money on them?
    Because the best components are expensive. The best "audiophile" capacitors can cost as much as 37p, that's seven times the price of the cheap ones!
    Do not get ripped off.

    For Example http://www.cricklewoodelectronics.com/Cricklewood/home.php?cat=111
     

  13. Rob DiStefano

    Rob DiStefano Poster Extraordinaire Vendor Member

    Age:
    71
    Mar 3, 2003
    NJ via TX
    no, the cap is still in the circuit to some degree, bleeding treble to ground.

    this is why and where a no-load pot mod makes sense.
     

  14. Rob DiStefano

    Rob DiStefano Poster Extraordinaire Vendor Member

    Age:
    71
    Mar 3, 2003
    NJ via TX
    the myths and bs continues, as long as threads like these perpetuate nonsense that guitar circuits are in some manner equated to the "audiophile" world. this thinking has nothing to do with guitars. it's waaaaay overthinking and overstating the simple truths inherent to these tools we call electric guitars.
     

  15. Rob DiStefano

    Rob DiStefano Poster Extraordinaire Vendor Member

    Age:
    71
    Mar 3, 2003
    NJ via TX
    how 'bout ... using a p/p tone pot, wire the cap to the pot's dpdt switch, set the pot to the value that sounds/works best with the bridge pup and have the best of both worlds - no tone pot/cap in the circuit for the neck pup, and a predetermined value to kick in with the bridge pup.
     

  16. bblumentritt

    bblumentritt Tele-Afflicted

    Dec 3, 2012
    Austin, Texas
    The best advice on this thread was "meter the cap value" a couple of pages back.

    Say your guitar has an .047 ceramic disc. You replace it with a .047 orange drop, and your "hear a difference." Maybe one of those caps is .056 and the other one is .038. They're both within tolerance.

    A 50 year old capacitor may have drifted way off spec, which may account for it sounding "warmer" or whatever.

    If you can, find an old TV repairman from the '70s or '80s, who worked with tube sets, but didn't work on tube amps. Ask him if an orange drop capacitor gives better picture or sound than a ceramic disk. ROFLOL.

    Orange drop type caps are good for one thing - stability. They're not as prone to environmental degradation due to the hard plastic coating, making them stable and having a long shelf life.
     
    Last edited: Oct 13, 2013

  17. Rob DiStefano

    Rob DiStefano Poster Extraordinaire Vendor Member

    Age:
    71
    Mar 3, 2003
    NJ via TX
    one of the few voices of reason and truth in this thread. :cool:
     

  18. jefrs

    jefrs Doctor of Teleocity

    Nov 20, 2007
    Newbury, England
    Yes, bleeding treble of ultrasound frequency.

    Nothing audible starts happening until the resistor drops to around 150k (about 8-9 on a 250k log pot). Do use a frequency meter. I have noticed that the no-load is noisier when switched out as there is an unterminated (open) connection.

    Upper harmonics of a guitar, on a meter, are around 8kHz.
     

  19. sjtalon

    sjtalon Poster Extraordinaire Ad Free Member

    Well here's the way I look at it. YOU say a no-load pot "makes sense", and with all the electrical engineering hocus pocus on the planet Earth taken into account, O.K,. agreed, it takes the cap out, that's just great.

    But if one (that being the OWNER OF THE GUITAR) installs a cap, and can A/B with the two different pots, and said DIFFERENCE ( never read so much to do about a DIFFERENCE) isn't HONESTLY worth a hill of beans to him one way or another, it DON'T MEAN JACK.

    Same with the grinding on and on and on and on...............about caps. If the OWNER of the guitar thinks or actually can HEAR a DIFFERENCE, and SAID DIFFERENCE is to THEIR LIKING, (or there is a productive gain in what they want) then that's what they should go with.

    99.9999999999999999999999999999 % of this is all subjective, as regardless of, again, all the electrical engineering hocus pocus on the planet Earth taken into account, there is one thing that is the ultimate ruler:

    [​IMG]
     

  20. bradpdx

    bradpdx Friend of Leo's

    Jul 16, 2006
    Portland, OR
    Why the cap doesn't matter

    The tone circuit thing. Always fun.

    Keep in mind that all of these instruments were designed by people using engineering tools to achieve some end. I am 100% confident the Leo Fender himself just ballparked values for tone circuits based upon a rough calculation, and ran with it. Nothing in the design shows any more attention to detail than that.

    Leo (and all the other electric instrument makers) were simply trying to offer something useful that could be implemented cheaply with passive components. Treble cut is about the easiest thing to do, and provides some color with bright pickups.

    The "back of the napkin" calculation that Leo/Seth Lover and everyone else does is this: you look at the load that the tone circuit presents to the pickup. If that impedance is significantly higher than that of the pickup, the affect will be minimal (tone control full up). If it is near or below the impedance of the pickup, the circuit will reduce gain. So they selected parts that fell into this range, taking care to reuse as many values as possible to reduce cost. Ergo 250K pots and 0.047mfd caps.

    This works out about right. Here is a graph of the impedance of a Tele tone circuit, which consists of only a 250K variable resistor and a 0.047mfd cap, as a function of frequency with the pot full up:

    [​IMG]

    I've also plotted a 0.022mfd cap for good measure.

    As you can see the cap causes the magnitude of impedance to rise at low frequencies, but the minimum impedance is set by the pot (250K). Even the rise at low frequencies is very small in the audible range.

    The effect is even smaller if we look at how gain is affected. The output impedance of pickups is a function of frequency, with the value very near the DC resistance at low frequencies, reaching a peak at the resonant frequency of the pickup in circuit. Resonance typically occurs in the octave between 5kHz to 9kHz for Telecaster pickups, and so is well above the range in which the tone circuit value rises.

    Assuming a DC resistance of 10K (a fairly hot winding), the loss due to the tone circuit is minimal:

    [​IMG]

    Recalling that 1dB is defined as the smallest change a human can perceive, it is clear that this graph represents a minuscule and inaudible change of output level due to the tone circuit, with a variation of less than 0.1dB over the entire audible range.

    What about no-load circuits?

    These charts just show that the determining factor for pickup load is not the capacitor, it's the pot. At resonance, the output impedance of a pickup is quite high, and is thus affected by the load presented by the tone pot. But at those higher frequencies, you can see that the specific value - and hence type - of the cap is irrelevant. The pot value dominates behavior, and thus removing the pot actually has an effect.

    A "no load" circuit really does change your sound by reducing the load on the pickup at resonance. The pickup is still loaded by the volume pot, cable and the impedance of whatever you are plugged into, and so the term "no load" is a bit disingenuous - "reduced load" is more accurate.
     

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