Centralab pots make a difference, WOW.

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

  1. Seanizle

    Seanizle Member

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    Just got done soldering in the volume pot and my god, there is an audible difference in tone and response compared to the RS pots I had installed in there; its like Pandora's tone box just opened up. I had installed a Centralab in the tone position of the bridge last week and noticed a change, but I had also installed some Lux Bees so wasn't quite sure. I wish I had taken a recording before to show what had happened, Ill break down what I'm hearing and what the values of the pots were and are now.

    Its a 2012 Gibson R8, I've got a vintage correct nylon nut, Faber locking bridge and tailpiece, Grover tuners and a Wolfetone Legend in the bridge wound to 8.3k with an A2 magnet. The pickup was always incredible, it has that bloom older PAFs tend to have, and the guitar itself is very resonant. What surprised me the most about this change is that I was expecting a much darker sound, as the Centralab volume pot read at 507k (the RS pot was reading 558k or something). What happened was that the highs were cut down a little bit, probably because of the -50k, but the whole sound became translucent. It was murky and thick before, but now its very clear and woody sounding. You can crank the amp and the treble up, and it will become thin but not ear piercing, if that makes sense? Before chords tended to mush together with overdrive, but now they bloom together. Buying some quality PAF style pickups got me pretty close, the Faber upgrades and the nut really balanced the acoustic sound of the guitar, but these pots have blown me away. I had a hard time believing that pots would affect the tone chain; I heard a few players say that 50% of the 50s Les Paul tone is in the control cavity, but after actually playing with the parts, its more like 60% guys if you factor in the caps.

    I had only seen a couple threads really break down the tonal changes these pots can have, so I'm leaving this here just as a reference. They are not cheap, if your looking for 50's Centralabs they are now $200+ on ebay, the 60's Centralabs are around $125-150. For reference it was a 1962 Centralab in the bridge that made the difference, and a 1958 Centralab in the tone control. Considering what I've spent on pickups alone, and considering what difference these pots made, I would say its worth it, even if they are over priced. I'm going to try and get a good recording of the guitar soon, and will post it here so you guys can hear it for yourself. :fingersx:
     
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  2. korus

    korus Senior Member

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    Thanks for your in depth review! And the values of previous tone pot and '58 Centralab pot are? Thumbwheels and posts for bridge are non-magnetic=brass, eg Faber wheels Gibson posts? A clip would be an icing on the cake...

    Often quoted , but rarely underastood truly: 'Everythig affects everything.' The more I know of tone of original Les Paul guitars, the more I get reminded of it.
     
  3. Seanizle

    Seanizle Member

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    Previous tone pot was around 520k, was a CTS audio taper pot, the 58 Centralab was 600k I believe; the thumb wheels and bridge posts were stock. I'm working on getting a short demo together that will demonstrate the tonal differences these Centralabs made. I always ask my girlfriend every time I change something if it sounds any different, with the nylon nut, Faber stuff, picks, strings, even pickups shes said no. She said wow this time, so I know I'm not just hallucinating. :thumb:
     
  4. scovell001

    scovell001 Senior Member

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    Seanizle,

    Thanks for your review, I'mextremely interestd in your findings, which sound great.

    So, to summarise, you had an RS superpot in there & swapped it for a vintage centralab with positive results.

    As youve mentioned, some sort of tone comparison would be have been great as would a capacitance reading out the jack, but hey.

    Theres a thread on here (i found it using a google search) where a member tests some allessandro pec pots against rs super pots, cts tvt etc & came to the conclusion that there wasnt much in it. In fact he preferred the cts tvt.

    Anyways, the point i was trying to make (in an open/constructive way) was what was it do you think is the route of the tonal change in this centralab pot ?

    I was gonna mention that perhaps by whatever means you managed to better ground the guitar which affected the tonal change, maybe ?
     
  5. edguidry

    edguidry Senior Member

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    I'd like to compare them to Bourns. Every time I replaced a CTS pot with a Bourns, it seems I've noticed a tone improvement but then again maybe that was just a placebo effect.
     
  6. jcsk8

    jcsk8 Senior Member

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    I would love to hear a test wich an off guitar controls with differen´t brands and values to compare that. I can´t hear much a difference in the time a desolder, solder a new pot. Maybe placebo. Of course when you change the value, like 300K to 500K there will be a clear difference. But...
     
  7. Seanizle

    Seanizle Member

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    It was a definitive change that the pot made, if anything the RS pots were better grounded before as a professional did it! I had read quite a few threads comparing the roll off of these old Centralabs, suggesting that maybe this was causing the tonal differences, but even with the pot at 10 it sounds very different. I've had some more time to sit in front of the amp and figure out what changed in terms of EQ, and its like the bass thinned out a bit, the highs smoothed out and the mids became punchier. I'm working out a video/audio recording to try and demonstrate this; as most people tend to have aftermarket CTS pots and boutique unpotted pickups, you should all hear the difference.
     
  8. Seanizle

    Seanizle Member

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    I could not tell a difference either, aside from roll off, between all of the different CTS variations. I was tempted to try Bourns, but they are 30+ dollars Canadian; I was able to snag a 1956 Centralab on Reverb for 60 dollars (bit rough looking, assured it works...we will see) reading at 600K. For the last year I've really been dissecting what tonally makes a 50's LP different from a modern reissue. With unpotted PAF pickups they pick up everything in the room, let alone vibrations in the guitar, so wood resonance clearly makes a difference, but I never believed that is what was giving these LP's THAT tone. After installing the vintage nylon nut and a decent bridge/tailpiece I got that mellow acoustic sound, Wolfes Legend pickup got me into that blooming/harmonic territory ala Billy Gibbons, but these Pots (and the Lux Bees, which as really great) completed the puzzle I think.
     
  9. DADGAD

    DADGAD Senior Member

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    Don't old pots tend to drift over time? Due to the carbon something or other? James (ReWind) explained it to me before but i forget exactly what was said. I have some pots from '71 and two of them read over 700k. Drifting was the general concensus on those.
     
  10. cooljuk

    cooljuk Transducer Producer Premium Member MLP Vendor

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    You got it right, bro. :thumb: The carbon traces in the pots drift higher in resistance over time, just like carbon comp resistors.
     
  11. Seanizle

    Seanizle Member

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    As I had repeaditly stated in the OP, the Centralab pot installed in the bridge that made the difference is 507k, the RS pot that was pulled out was almost 560k. There is something else going on with these pots, specifically when placed in the volume control; I'm no audio engineer by any means, but there is a filtering of the sound that other modern pots do differently. If your in a grind core or death metal band cranked through a 5150, the lack of bass and the mellowed highs might not be ideal, but we are talking about vintage sounds here. Scratch the "higher value pot opening up the guitar" off your lists, I had 1 meg CTS pots in my neck pup and all it did was thin it out; honestly these 507k Cebtralabs in the bridge opened up the pickup more than the 1 meg CTS pots, just in a positive way with a balanced eq.
     
  12. spitfire

    spitfire Senior Member

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    Whatever difference you are hearing is NOT do to the brand, quality etc of the pots. The ONLY thing that is going to affect the tone produced is the value of the pot.

    There can be differences in the quality of pots affecting how long they last, scratchiness etc. Also, difference in the taper can greatly affect how the sound responds to changes in pot position.

    But again, quality or taper will not affect tone. Only the pot resistance value will. And sure, if you want to be anal about it, there is probably some electronic difference in pots that would affect radio frequencies. But these differences are way below insignificant at the audio frequencies produced by guitars.

    If the OP made a change they like, great! But, any changes in tone are not due to the brand of pot put in.
     
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  13. edguidry

    edguidry Senior Member

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    Other factors are capacitance and inductance, but I don't think you usually see those factors in a potentiometer. Also, in a pot wired for a guitar volume, there are two things going on. Series resistance and resistance to ground. It's a voltage divider that's variable and while one resistance increases the other resistance decreases. And resistance affects frequencies differently, especially in the treble region. When the pot is at "10" though, there should be negligible differences, though. You should be able to solder in a 500k resistor to ground and get the same sound.
     
  14. Seanizle

    Seanizle Member

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    There is some kind of a filtering going on, specifically with the volume pot, that smooths out the highs. There are a few videos of 59 LP's that demonstrate this, one with Greg Koch on YouTube playing an orginal 59; there is an acoustic quality to the highs. I have been fiddling with the volume pot and realized that once and a while, when I crank it back and forth back up to 10, the harshness returns to a degree. I am going to start another thread looking into this, it isn't a cold solder joint, and is not a problem with the tone pot or the PIO capacitor as these were both installed with an RS volume pot and this did not happen. It is also not the taper, as it will click all the way on and the sound will be different; I'm thinking there is something wrong with the track of the pot, as its over 50 years old, but will appreciate some insight into this from other owners of Centralabs or vintage instruments with them installed. The change in sound that I first described may just be a result of aging pots; all I know is there was in fact a change in the sound, and it was not a result of the -50k.
     
  15. cooljuk

    cooljuk Transducer Producer Premium Member MLP Vendor

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    If you can tell what pots a guitar has by listening to a YouTube clip you should pursue a career in forensic audio.



    Sounds like your pot is failing. It happens. Ever have a car stereo or old TV with a scratchy volume knob? Same thing. I know it's not scratchy sounding but you're talking about the near full on position and getting intermittent opens. Not the near full off position. Someone pulled it out of a piece of gear for a reason. Maybe it was failing?

    ...this is assuming you cleaned the 60 year old pots before installing them. I hope so!



    Also, volume pots DO filter the treble. Any volume pot does this. It's not something magic to your Centralab. This is why some players clip the volume pots out of the guitar altogether and some Fenders are sold with no-load pots.
     
  16. Nick-O

    Nick-O Senior Member

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    caig deoxit D-5 contact restorer is your friend!
     
  17. Emiel

    Emiel Senior Member

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    To the OP, can you do a comparison audio/video file of the Centralab vs the RS pot? I am sure that quite a number of people would be very interested in the differences in tone...
     
  18. Seanizle

    Seanizle Member

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    The whole purpose of this thread and venture was to see if Centralab pots make a difference when paired with PAF style pickups. Yes I know volume pots filter treble, what I found was that these pots filter the treble differently; this should really come as no surprise as the construction is, apparently, different from modern CTS pots. My tonal experiment here was to test how much of a difference and to my ears, it is noticeable, especially when paired with a very open, touch sensitive pickup. Not everyone can afford to buy 150 dollar, 60 year old pots, and as I described earlier the tonal changes they made may not be to your fancy; depending on multiple factors they may not make a difference. There is also the risk that yes, they were pulled out for a reason because they were faulty, although in my case I made sure the volume pot was from a reputable vintage seller on Ebay, who claimed the pot was cleaned and fully functional. There is zero scratching in the pot and I am honestly still trying to determine if it's the pot at all, but I'll look into the contact cleaner thanks for the info guys.

    I'm working on getting a good recording, not sure if I'll pull it and compare directly to the RS, but I'll make sure to demonstrate what I'm describing.
     
  19. spitfire

    spitfire Senior Member

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    It makes no difference what position the pot is, if the resistance is the same the tone will be the same. The pot taper will affect where you turn the knob to get a specific resistance split, but this of course has nothing to do with tone.

    The entire circuit behaves as a filter, all the components have an effect. Even internal cabling can matter if there is enough of it. However, with pots it is the resistance value and only the resistance value that affects the guitar. While other aspects of a pot such as taper and even stiffness are important, these do not affect tone.

    There is no magic resistance properties that vary between pots. Resistance is resistance is resistance in this application. This isn't going to change between brands or age of a pot. As I mentioned before, a pot does have other characteristics that can affect signals. But these only begin to come into play at frequencies much higher than audio frequencies.

    Again any tone difference you are hearing can only be due to the value of the pot. Get two pots with the same actual resistance value and they will sound the same. It's impossible for them to sound different in this application.

    Keep in mind that if you turn the knob off of 10, and think there is a difference, this is due to taper. However, both pots will sound the same, they just may have to be in two different positions. I.E., one on 7 and the other on 5.

    You originally mentioned the pots had a resistance difference of about 50 k and that you heard a reduction in highs. This of course is exactly what one would expect. Concerning other changes, while a lower resistance cuts highs, it also moves the resonant peak of the circuit and generally alters the filtering. It doesn't simply cut highs. It quite possible the it modified the overall circuit in a way you like. But any other pot would do the same thing if it has the same resistance value.
     
  20. ErictheRed

    ErictheRed Senior Member

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    Joke thread is funny.
     

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