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Looked inside my Les Paul Traditional and was very surprised...

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by brewbaker, Dec 3, 2017.

  1. brewbaker

    brewbaker Supporting Member

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    ...very tidy factory wiring, strange center terminal thingy where the jack wires connect to the circuit, but the surprise was that the tone caps were tiny ceramic discs. I know that this was common on Fender guitars in the early days but on a Gibson I expected to see something else. Immediately my "should I upgrade" brain kicked in. What is the consensus these days? Would it sound that much different if I put in PIO or orange drops or Mallorys? Incidentally, the reason I finally decided to look inside this guitar which I've owned for two years was in anticipation of changing over to 50s wiring. Since the caps play such an important role with that is why I'm wondering about the upgrade. All opinions welcome!
     
  2. walterw

    walterw Gold Supporting Member

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    no. same-value caps sound the same in a guitar, the rest is snake oil and placebo effect. in fact, above about "5" on the tone knob the value doesn't even matter, you can literally put in a piece of straight wire and it'll sound the same.

    now if it has the 300k linear volume pots, changing those to 500k audio will improve the clarity and give you better clean-to-crunch control from the volume knob.
     
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  3. brewbaker

    brewbaker Supporting Member

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    Thanks. I thought about the pot values and have been trying to decipher the Gibson-branded cases and the numbers but need to pull one out to be sure what they are. So your opinion is that all the gourmet, boutique tone caps are not worth the bother/cost?
     
  4. Oinkus

    Oinkus Member

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    Cap value is all that matters and how close to the value it actually is not what it is made of.
     
  5. KGWagner

    KGWagner Member

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    Not in a million years. What matters is the capacitive value of the device/element. Everything else, as far as guitars are concerned, is pure unadulterated snake oil. The marketing weenies are eating a lotta guy's lunch.

    The only reason to use an oil/paper (or any other exotic construction) cap is if you need a very high dielectric strength. Dielectric strength is the measure of a capacitor's ability to withstand a given voltage without shorting out, and is set by the insulator material and thickness between the plates of the capacitor. The voltage in a guitar is measured in thousandths of a volt. Very small, is what I'm saying. So, do you need a cap that can withstand 800 to 1200 volts? Not in this world.

    A .022uF oil over paper cap will respond to frequency changes exactly the same as a .022uF ceramic as long as you don't exceed the voltage rating of the cap. The tiniest deliberate caps in the world can withstand guitar pickup output voltages. They're practically nothing.

    To be fair, there are differences in capacitor performance in other applications, which is why there are so many varieties of them. But, it almost always involves voltage ratings and frequencies that you'll never encounter in a guitar. Also to be fair, Sprague's "Orange Drops", while overrated for guitar application, are as common as cockroaches, so even though they're more than you need, the price is right. They make about 80 bajillion of them a minute, so why not use them?

    But, in the end, those little ceramics that aren't much bigger than a speck of flyshit will get you the same tonal performance in a guitar circuit for $.05 that a $25 paper/oil part will.

    And as long as I'm on a rant... don't pay any attention to those YouTube videos where some genius hooks up 12 different caps on a switch to prove mylar sounds different than paper/oil or polystyrene or [insert long list of dielectrics here]. You'll notice they never bother to actually measure the caps. They assume because it's marked XXuF, that that's what it is. Nothing could be further from the truth. Caps and resistors are some of the sloppiest components in the world. Tolerances are all over the place and can be as high as 20%. Any difference they can hear is due to the fact that they're measuring different values, not different constructions.
     
    Last edited: Dec 4, 2017
  6. walterw

    walterw Gold Supporting Member

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    the tones are guaranteed to be 500k audio (leave 'em in) but here's a neat trick i learned on these very gear pages for measuring volume pot values without de-soldering anything!

    plug a short cable into the guitar, dime all knobs and switch to one pickup. put your ohm-meter leads against tip and sleeve of the other end of the cable. you should essentially be getting the resistance reading of the pickup (minus a few hundred ohms from the pots being in parallel with it).

    start slowly turning the volume down; you'll see that resistance reading start to rise. keep going until that reading "peaks" and then starts going back down again, which it will do partway through the rotation.

    once you've found that peak resistance value, multiply it by four. the result will be in the very rough ballpark of what the pot itself is.

    if that peak reading is in the 60kΩ range you have a 250k pot, if it's in the 70s or 80s you have the dreaded 300k linear gibson volumes, and if it's in the 120s then you already have 500k volumes.
     
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  7. brewbaker

    brewbaker Supporting Member

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    Thanks all the great info. I determined that the v pots are 300k and the pots are 500k. Since I wanted to try 50s wiring which involves resold earring the caps I decided to put in some RS branded caps I had stashed, with another experiment being a .015 in the bridge position. So far I'm liking the result.
     
  8. VaughnC

    VaughnC Supporting Member

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    While I understand the math behind capacitor reactance and the like, one thing I noticed when I replaced the stock tone cap in my favorite Strat with a PIO type of the same value is the sweep spread of the tone pot seems different. The stock cap was almost an on/off switch as the tone control was rotated...whereas the PIO gave me a little more spread out area on the tone pot making it more useable. The tone itself didn't change though...so it still might be worth trying. Can't explain why but that's the way my ear hears it.
     
  9. 9fingers

    9fingers Supporting Member

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    Dandy trick Walter- thanks for sharing!
     
  10. walterw

    walterw Gold Supporting Member

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    The two most likely reasons are that the actual cap value was different (age, tolerance, whatever) or you heard the new cap as being “better” because it was a fancy new cap.
     
  11. VaughnC

    VaughnC Supporting Member

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    Well, being the analytical person that I am and being employed in the electronics industry with a degree, I measured both cap's values and they were very close. The sound didn't change, only what I perceived as the spread on the tone control. Nope, not scientific by any means...but the Strat was very familiar to me. Maybe, if you know what I mean, if something changes with a guitar that's very familiar to you, you know something is different that no one else would detect. It was that kind of thing. Subtle, but the difference was there with a different type of tone cap of the same value. My electronics training & experience says BS...but what can I say, I hear it ;).
     
  12. Lobotomie

    Lobotomie Member

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    Good tip Walter.

    I see how that works for a linear pot: once you're halfway on the knob, you end up with 125k and 125k+pickup DCR in parallel, which is roughly 60k (for a 250k pot).
    Does that work with a logarithmic pot though? I know "audio pots" differ in taper, but what's a typical value for 250k log halfway?
     
  13. bob-i

    bob-i Member

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    Being an electrical guy you know about all the other specs associated with capacitors. Most important would be ESR and leakage current. Admittedly with the low voltage and current in a guitar the leakage will most likely not have an impact, but ESR may.

    in the end your ear is the best judge. I found a pretty dramatic difference in tone on my Epi LP Jr when I switched from the ceramic to a PIO, other guitars seem to sound better with ceramic, others with PS6 Orange drops.
     
  14. walterw

    walterw Gold Supporting Member

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    aha, it's the two "halves" of the pot in parallel! that makes sense conceptually (i just knew the trick, not how it worked :oops:)

    with an audio pot that "peak reading" where the two halves are closest to balanced will just happen somewhere other than at the halfway point in the rotation.
     
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