Plot your pots

goodvibes

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I am making a comparison graph of different potentiometer tapers that have been used in Historics, as well as, several aftermarket brands. There are many options out there and I think it would be very helpful to see a visual comparison to the tapers used in the ‘50s Centralab pots. However, I’m missing the data from the Centralabs because I don’t have access to any originals. Would anyone out there with some 1950’s uninstalled originals be willing to measure the pot resistance at each knob position from 0 to 10? It’s not really that hard to do but it would require that you have a resistance meter or multimeter. The pots would need to be in fairly good shape. I would settle for just one data set but the more the merrier. I will share the data from all the pots that I have compared to date here on the MLP forum. I have actually already posted my data in an older thread but I have more data now. We can always add more brands or years to the chart in the future. I know that there is some information out there mostly from aftermarket pot vendors but I prefer data from actual vintage centralab pots from independent owners (not affiliated with aftermarket potentiometer manufacturers).

Well, I know this is a longshot but I thought I’d give it a try because I think it would be very helpful and very interesting to see these comparisons visually.

Take care everyone,
Keith
 

goodvibes

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Here is how I measured the uninstalled pots. No need to get fancy, a smal piece of paper or cardboard can be used to mark the reference point for the knob 0 -10 position. Negative (black lead) to the pot case grounded lug and positive ( red) lead to the center lug on the pot. Measured resistance at each step 0-10.

This is a good way to check your vintage pots to make sure they are not corroding while in storage. Even sone of my 10 yr old pots were getting oxidation on them from sitting around and not being turned for so long. If they are getting corroded or if they have bad spots the resistance readings will jump or be inconsistent. I used Fader Lube to clean them up and get them to read better.
BEBA857B-71F6-44D2-99AB-21F2883C4A20.jpeg


0DE18CB1-10A1-48B3-9232-1C218536C1C0.jpeg


6D4715F3-4CBC-4444-872E-2F46BE2BE3FE.jpeg
 

Knoby

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Great idea! I hope you get the data that you need.

Thanks in advance for putting in the time to do this. To everyone that contributes.
 

goodvibes

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I’m not the first to come up with this idea. I just found a previous post in the tone freaks forum from A MLP member.


He mentions that he has some vintage Centralab pots that he was planning to measure but he didn’t add them to his charts for some reason. If I can’t get some original pot data, I will just do a curve fit of the Centralab curves. Stay tuned…
 

Sct13

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I have one Centra Lab Pot, it is used....its about 475K (I think) or at least under 500k
 

goodvibes

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Last night I was able to research a little more and I located a post on a different forum of a '59 Centralab Les Paul pot. Sct13, if you want to see how yours compares send me the values when you feel up to it. Here is an interesting plot of older historics and the ever popular VIP pots vs a genuine '59 Les Paul pot and the Centralab Spec curve for the 500K pot C2 taper which was used for the '50's Gibsons. Some notes about the plots:

1.) I only took readings from the knob steps 0-10 and that is why the plots are not smooth curves like the C2 taper spec plot. In order to smooth out the curves, I would need to take many more data points and it is just too much work.

2.) The pots in my '95 Historic GT are a reverse taper! Weird!! No wonder I hated them and changed them out.

3.) It appears that by '98, Gibson started using better pots (maybe before '98 but after '95??). In any event, The '98 pots are extremely close in value and taper to the old Centralabs which was a surprise to me! I believe in 2011 Gibson started selling Historic Spec audio taper CTS pots which are very close to vintage as well (not sure about the tolerances though.) People over on The Les Paul Forum were raving about these back in 2011.

4.) The VIP pots are also very close but were spec'd to be >500K max.

pot-tapers-1.png
 

goodvibes

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Here is a comparison of Crazyparts TVT CTS 500K pots. The taper is also very close but not really better than Gibson Historic spec or VIP pots. Also, Crazyparts are pricey and they refused to send me a matched set at or above 500K :(

pots-2.png
 

Sct13

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I will as soon as I get everything together (we just moved in June) still unpacking LOL But.....I know where everything is ....

I remember this thread from before ....
 

Sct13

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It wont be hooked up to a cap....or another pot for that matter
 

goodvibes

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Well 2007 might have been a great year for historics, however, not such a great year as far as pots matching vintage specs. The tapers on all eight pots that I measured more closely approximate a linear taper than an audio taper. I did see that a gentleman on another forum posted that Gibson Custom shop was using linear taper pots from 2003 - 2008.

pots-3.png
 
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goodvibes

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It wont be hooked up to a cap....or another pot for that matter
I don't think it matters if a cap is soldered to one of the lugs but the pickups cant be soldered to the pots. I also removed the buss ground wire just to be sure.
 

goodvibes

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Anyone have any other types they want tp plot? I.e., Precision electronic Components (PEC) - you know the $40 ea. ones. How about newer Gibson Historic spec, Bourns, Demarzio? I have some data for RS Guitarworks pots from 2009 but I'm not sure if these are "Super Pots" because I'm not sure when they started marketing those.
 

goodvibes

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Here are a couple new pots from eBay seller The Art of Tone (TAOT) These are his custom 550K audio taper pots. These are also very close to vintage with a bit more gradual transition in the "knee area" (from 5-7 knob position).

TAOT_pots.png
 

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