Centralab pots make a difference, WOW.

Discussion in 'Tonefreaks' started by Seanizle, Jan 21, 2017.

  1. cooljuk

    cooljuk Transducer Producer Premium Member MLP Vendor

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    If the point of your swap was a critical listening comparison, you should have chosen to compare two pots of equal value. Nothing critical about it, otherwise.
     
  2. el84ster

    el84ster Senior Member

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    There certainly is a difference in parts. But those who can't hear it (or more usually, haven't experimented themselves) will always criticize those who can. I've built all manner of audio tube gear (and guitar electronics) over the past 20 years and know this for certain.
    I mostly stopped posting my findings because of those critics.

    But there is a difference, FWIW. Also there is a modern pot that sounds better than the old Centralabs, they're mil spec and only go for about $25 ea. PEC guitar pots.

    My hat's off to the OP for sharing.

    How about this: the original '60s vox wah and the modern recreation don't sound anything alike. They use the exact same spec for all the parts though...hmmm. Yes different materials matter.
     
    Sterling # Sound likes this.
  3. Antigua

    Antigua Senior Member

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    Maybe you didn't really hear a difference. If people want to find something, they will find it. If people want to hear something, they will hear it. If you just spent $80 on a part that usually costs $4 or less, you really hope to hear a difference.
     
  4. korus

    korus Senior Member

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    Or maybe he did hear a difference which he can identify each and every time in double blind test 100 out of 100 times. People who do hear do not need scientific proof in order to convince those who do not hear. Cause they hear.

    It is rather simple - some do hear, some don't. It's the very nature of being - a human being.
     
  5. Antigua

    Antigua Senior Member

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    You can't just pretend you performed a successful 100x double blind test when you did not. This giving people the benefit of the doubt would never fly if the stakes we're anything beyond trivial, but since we're talking about guitar, truth is allowed to be relative.
     
  6. spitfire

    spitfire Senior Member

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    Some of these things certainly do make a difference in tube gear. Given that circuits in tube gear often run on hundreds of volts DC. Resistors and such do have non-linear characteristics when operated with larger voltages. These differences are small, but are documented for tube circuits.

    But that's a very different situation than the very low voltage circuits used in guitars.

    As far as I know (and I've looked), no one has shown any differences in capacitors or resistors in guitar circuits using a double blind test.

    People hear all sorts of things that aren't there to be heard. It's been documented over and over again. Our expectation bias is overwhelming when it comes to what we hear.

    The OP may have heard something because of different resistance value. What he didn't hear was something due to some difference in material etc.
     
  7. el84ster

    el84ster Senior Member

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    If someone hasn't swapped and tired it themselves, I'd say they're not really qualified to make claims against the OPers findings. :cool:
     
  8. spitfire

    spitfire Senior Member

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    I think my 40 years of electrical engineer experience makes me more than qualified. I don't have to jump off a cliff to know it will hurt me.

    While there are grey areas in some subjects where it's fair to point to first hand experience. This isn't one of them. There is no know reason that anything beyond the resistance value itself would create an audible difference in this application.

    It's well established that anecdotal evidence in audio is pretty close to useless. Expectation bias has been very well documented when it comes to audio perception. Simple put, people hear what they want expect to hear.

    In this case the OP noted a significant difference in the resistance value. So he may very well hear a difference caused by that. But there is NO reason to believe this is due to the make, model, age, or special mojo of the pot. There's simple nothing to justify that those things matter in this case.

    This is a case where anyone claiming, with certainty, that make, model, etc. of the pot affects tone, needs to perform a double blind test to prove it. As with a lot of general claims like this (not referring to the OP), no one ever produces test results that prove. Just, "I hear it, you can't, I guess your ears suck."

    When it comes to unsubstantiated claims, it's foolish for a person to believe their own ears, it is beyond absurd to believe someone else's ears.

    This would be completely different if there were any reason to believe there were characteristics of the pot, other than resistance value, that could cause an audible difference. If there were, it would be reasonable to hypothesize that due to these characteristics, there is a difference. But, even then, you need proof that it matters, before you can run around claiming it does matter.

    In this case we don't have any plausible explanation for anything beyond resistance value that would matter.
     
  9. Antigua

    Antigua Senior Member

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    This is wrong on a couple levels.

    One, you certainly don't have to believe anything someone puts forth, just because you haven't lived the experience from which they claimed to have derived insight. I have not been to the top of the mountain, but nevertheless I do not believe that God spoke to you up there.

    Two, even taking the claim at face value there are problems. If a persons says "though I did not use a ruler, it's ten feet", the fact that they admitted to not using a ruler gives you reason to not accept that it was, in fact, ten feet.
     
  10. Dica

    Dica Senior Member

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    You can easily adjust the Ohm on any pot.
    I raised mine from ca 430 to between 650-780.

    It was easy to do and the guitar was there in the burst territory.
    Sounds like a Peter Greens Burst and cranked very similar to Jimmy Pages.
    Bright, cutting and Evil.

    Just scrape the carbon.
     
  11. Jason Taylor

    Jason Taylor Senior Member

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    Amen!

    Jason
     
  12. Jason Taylor

    Jason Taylor Senior Member

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    I noticed a tone difference with different pots in some experiments I tried. I don't know if it was the slight differences in pot values that naturally occurs with pots even if the same brand, or from materials inside the pots themselves, or a combination of both, but definitely if someone goes out and buys 2 500k pots from a store they can sound different!

    I also thought I read somewhere once that the materials used in pots can make a tonal difference, which is what the OP refers to... but I can't remember where the heck I read it since it was many years ago.

    Jason
     
  13. spitfire

    spitfire Senior Member

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    Jason, I'd be interested to see anything you have showing that pot material makes a difference. I really don't think it does. But would like to see anything to the contrary.

    While no electrical component is truly ideal in behavior, a guitar signal is not very demanding. It's very low frequency, very low voltage, and very low current.

    I just found this paper online that discusses passive components. I didn't read all of it, but it describes some of the parasitic aspects of components. Though they almost universally apply to high frequencies, well above audio. Or apply to things that just don't matter in a guitar, like a slight change in resistance due to temperature.

    I did see something under potentiometers that was intriguing concerning vibration. It would seem possible that playing with a loud amp, could vibrate the guitar and affect the pot wiper contact. But, just because it might doesn't mean it does. Just something to consider.

    http://www.ti.com.cn/cn/lit/an/sloa027/sloa027.pdf
     
  14. Jason Taylor

    Jason Taylor Senior Member

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    Spitfire,

    Yeah I wish I could remember where I read that article! I believe it referred to the quality of the carbon tracings on the ring inside the pot and concerned different qualities of carbon used by manufacturers and the amount and thickness or something or other.

    Im not arguing one way or another about this issue I just know in my experience changing pots I noticed some sounded better than others of the same value, and heck if I knew why lol!

    About the small current inside a guitar that you mention... does it matter that the small current gets amplified by the amp so the subtle differences inside a guitar can be more audible than people dismiss? Just wondering is all :)

    Jason
     
  15. Jason Taylor

    Jason Taylor Senior Member

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  16. moreles

    moreles Senior Member

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    The difference in basic pot values cited seems to me enough to account for a tonal difference. I fiddle with pot changes all the time and it seems to me common enough that value differences well below the macro 250, 300, 500 levels usually cited have an audible impact. (This gets more complicated if you generally play and listen with the dial set somewhere in the middle where different taper can come into play.) As others have said, the make of the pot is relatively inconsequential compared to exact value and taper. But, again, I would always look to exact metered value as the consequential factor for tone, and I think a 5% difference or more would be audible, particularly in parts of the tonal spectrum.
     
  17. CCK

    CCK Senior Member

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    ^^This!^^ Resistance is resistance.
     
  18. Jason Taylor

    Jason Taylor Senior Member

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    I asked before but no one fielded this question so please allow me to ask again:

    About the small current inside a guitar that people mention... does it matter that the small current gets amplified by the amp, so the subtle differences inside a guitar can be more audible than people dismiss? Just wondering is all :)

    Jason
     
  19. spitfire

    spitfire Senior Member

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    Just because the currents and voltages are small and get amplified, does not mean they are more susceptible to filtering (tone shaping), distortion or some other effect. The effects on a signal are proportional to the signal itself. So for example, 1% of a small signal or large signal, is still 1% of the signal.

    This for example is why we typically relate the effects of volume, EQ or other change by decibels (dB) which is a proportional change. A 3 dB change is the same proportional change regardless of the strength of the signal.

    There are of course other things not proportional to the signal, like noise (usually hum). But that's not what we're talking about here.
     
  20. Jason Taylor

    Jason Taylor Senior Member

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    Makes total sense! Thanks!

    I guess what I'm wondering is that I personally found a difference in wiring my guitars using a super low capacitance cable like the inner portion of a George L's cable, and using a seperate grounding wire... as opposed to using a braided shielded cable to wire the cavity for example.

    I dont know why it sounds slightly better... more open and clearer... but it does.

    When I posted about it I got trolled that because of the small signal in a guitar there was no way I could hear the difference.

    But I did hear a difference... so I was wondering if I could because a good tube amp was amplifying the small signal so therefore I could hear the difference.

    Does that make sense?

    Jason
     

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