Audio vs Linear pots and values
If you've been reading articles about dating a vintage guitar, you may well have come across mention of pot codes. The pots, or potentiometers to give their full. K not as bright/open as a higher value pot, and Gibby. Join Date: Mar ; Posts: 1, . I had referenced RS Superpot, the DiMarzio, and a basic CTS in the pot A. has 25/75 curve, which means that at "5" it divides k = k + k (e.g. like vintage, or custom taper RS, Dimarzio, Hamer ). Guitar/Bass Potentiometers at Europe's largest retailer of musical instruments - fast delivery, Day Money-Back Guarantee and 3-year Thomann warranty.
The next two numbers after the manufacturer number are the year, and the last two numbers are the week of the year the pots were made. So a pot stamped is a CTS pot made in the 33rd week of Note that this does not mean a Muff with a pot was actually made init just means it was not made much earlier than The Muff could have been made months or even years after the pots were purchased as it is known that Electro-Harmonix bought the pots in bulk, as did Fender, and other companies at the time.
Stackpole and CTS made the pots in large runs also, so they may have shipped pots dated earlier than the year Electro-Harmonix ordered them. This just gives you a ball-park age for the Muff. Some Triangle Muff pot codes are datedtwo years earlier than the founding of Electro-Harmonix! Even buying new CTS pots today does not give you an accurate age because they are dated several months in advance of actual manufacture. The Russian made Big Muff pots also lack date codes.
Logarithmic taper pots, or audio pots, will also work for the volume pot and sound better, but they are more expensive than linear. Russian made Big Muffs have Russian made pots, usually k linear taper.
Reading pot codes
You can use k audio log taper for the volume pot. Various issues about potentiometers are discussed including some numbers often found on Gibson pots, pickup loading effect, resistances in parallel, disconnecting the tone pot. I suspect the way things work with those numbers seen on Gibson pots is that they are some kind of part number and instead of identifying a specific Kohm value, they may instead just simply indicate either the tone pot or volume pot of that day, that era.
There was a time when they did use K volumes and K tones, Ks starting around July and later K tones. In having looked at various Gibson pots, here's what I noticed in terms of part numbers and values: I ordered 6 because I of the variances in resistance. Since I can only use 4 and I'm assuming that I use the top 4 in the listis there an optimum position for the pots? BGWN Yes I would use the two largest value pots for the volumes, and the next two largest for the tone controls.
The largest value would likely be best used with the bridge pickup. I would also suggest that you review the thread from a little while back in the Tone Zone area titled "new insight into pots". There I describe how you can mod the pots to increase the value of the resistance, get any pot that measures well down in the K range up to K or maybe more.
Les Paul Forum Member Ok, what about lowering the resistance? I have a couple of older cts and an old gibson that measure upwards of K.
It's funny how these vary so much. I had an SG from the early 70s that had a pot actually measure K! BGWN You can achieve a lower net resistance, for the purpose of tweaking to get just the right amount of pickup loading, by using a resistor in parallel with the pot in question typically a volume pot. The math of resistances in parallel could be expressed such that the sum of the inverses of the resistances equals the inverse of the net resistance, did you follow that?
In more symbolic algebra terms, using Rpot, Rextra, and Rnet: A K pot with a 1Meg parallel resistor would produce a net K. I put a 1Meg audio pot in my R9 for the bridge volume pot, intended for using higher output pups, but I later added something like a 1. Les Paul Forum Member While you're crankin' out the goods Could you explain why a guitar sounds brighter with no tone pot versus the same guitar with a tone pot set on 10?
Is that enough loading to make the difference? Also, if you have two guitars setup exactly the same except one guitar has a K tone pot and the other has say a K tone pot or whateverwould there be a difference in sound if the tone controls were set on 10 on both guitars?
Also, does the resistor mod you mentioned above mess with the taper of the pot any? BGWN In the past some have commented that their head aches after reading one of my explanations, that they needed an aspirin. As such you have all been warned. Let's start with your first paragraph, the no tone pot versus tone pot set on First when you said "When on 10, a pot usually seems to measure around 1K to 3K ohms.
A pot is a resistance with terminals or connections at either end of the resistance, plus a third middle terminal that goes to a wiper that makes contact somewhere along that resistive track.
CTS vs. ALPHA. | Telecaster Guitar Forum
When on 10, full on, a pot should measure close to 0 between the the middle wiper contact and one end, while the full value of the pot between the wiper and the other end.
Typically there will be some residual contact resistance even at full on, but it probably should be less than about 75 ohms. As such with a volume control the input to output wiper terminal connections should measure close to 0 typically less than 75while with a tone control the opposite sort of arrangement is used, the measurement would be the full value of the pot, K or whatever.
Okay, as to the "to tone pot or not to tone pot". First keep in mind how a capacitor behaves, the higher the frequency of a signal the lower the impedance or resistance of the cap. As you turn up the tone control you are introducing some resistance in series with the tone cap, which progressively reduces the effect of the tone cap.
Dating Guitars – Pot Codes
When you have the tone control on full the amount of resistance added in series with the tone cap is sufficient to make the tone cap's effect relatively neglegible. With a volume control you really are turning up the volume, turning up how much of the signal you are selecting.
Now with the tone control full on If you consider what the situation would be for the higher frequencies, where the impedance of the cap is relatively small, effectively you still have what amounts to a K tone pot in parallel with the volume pot. As such the net loading on the pickup is two K resistances in parallel, thus only K. The point is that even with the tone control full on there is still a small loading effect on the pickup at the higher frequencies.
This would better allow the natural responsiveness of the pickup to be realized. Somewhere on the Seymour Duncan web site they had some graphs of pickup output versus frequency response. The variable between each graph was the amount of loading applied the pickup, K, K, K, 1Meg, or an open circuit virtually no load.
Note that it might be quite possible to go too far. Some people have tried using the lower output cleaner weaker pickups and found that without a tone control or with a 1Meg volume they start to sound too harsh, too brittle, not quite right.
What they are probaby describing is the upper mid response of the pickup being allowed to become too pronounced for their tastes. The loading effect is due in part to the idea that a guitar pickup is NOT a low impedance device able to cope well with any serious load.
Let's digress and use the audio power amp for an analogy. An amp that may be fine for an 16 or 8 ohm load may get into some trouble if you try to drive a 4 or 2 ohm load.
There is an internal "resistance" of the output stage of the power amp. Say it was 1 ohm. If you tried a 2 ohm load the situation gets worse. Generally speaking pro audio PA power amps that can handle 4 or 2 ohm loads have to have a serious output stage with many output power transistors in parallel to get the internal resistance of the amp down to a small fraction of an ohm.
The analogy applies to some extent with passive guitar pickups. A traditional PAF style pickup with 42 gauge wire having a total coil resistance of around 8K may be okay with those K pots Gibson has been using in the production LPs.
If you wanted to keep the loading effect to a minimum you probably would want to have at least a 35 or 40 to 1 ratio between the value of the pot and the pickup coil resistance, just my rough rule of thumb.
Part of the effect with pickups is also due to the very fine wire gauge used in the coils. You cannot get all that much current happening through a piece of 42 gauge wire before it would overheat and self destruct. The light gauge coil wire contributes to the pickup being sensitive to the pot loading effect.
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Regarding pickups and coil wire, if you took a regular humbucking pickup and wound the bobbins crammed full with traditional 42 gauge wire, you could only get maybe a total of 9.
If a pickup measures over 10K, it would have to be using a lighter gauge wire, probably either 43 or All other things being equal a pickup wound with lighter 43 or 44 gauge wire might exhibit a slight loss in response for the higher frequencies compared to 42 gauge wire.
As a result most pickups that are wound somewhat on the strong side using 43 or 44 gauge wire also use at least an Alnico 5 strength magnet or an even stronger ceramic magnet. The Gibson T and T both use 43 gauge wire, and considering the typical resistance reading of a T the wire must really be crammed in there.
The Duncan Distortion uses 44 gauge wire. If you have swallowed all of this up until now, you probably could answer the questions in your second paragraph. If using a K versus K tone pot, the K pot would produce a slightly livelier or brighter tone.Guitar volume pot listening test 500k vs 250k on Humbucker and Single Coils
The reason would be that the K pot would be a lower load on the pickup than the K pot. With the last question, let's compare say a K pot to a 1Meg pot with a 1Meg resistor connected across it to produce a net K resistance. Typically this concept would only apply to a volume control. In general the idea with volume pots is not the exact amount of resistance between the wiper and the end terminals, but rather an issue of RATIOS.
A volume pot is used to pick off a portion of the signal, thus the full term potentiometer. You may also hear the electronics phraseology of voltage divider. If you had a K pot set such that the wiper to end terminals resistance was exactly half of the total, K, the output terminal would have K to ground while the input terminal would have K to ground, so the output would be half of the input signal voltage.
Thus the resistive element of the pot with the adjustable wiper allows a portion of the signal to be picked off, based on the ratio of the resistances. If you had a 1Meg pot similarly set to have K from the wiper to each terminal, similarly you would have a voltage divider such that K out of 1Meg or half of the input signal would be at the pot output.