### Post by antigua on Jan 16, 2018 13:57:34 GMT -5

Maybe so! Since this scatter plot analysis suggests that DC resistance is a reasonably close indicator of inductance when the wire gauge is normalized, and because DC resistance is directly related to wire length, it means that you can fairly reliably trace a line from one to the other.

When people say a pickup is "hot", it means two things: louder and darker. The darker part comes from the inductance, because a pickup is an LC low pass filter, and a higher inductance "L" means a lower pass. As for louder, every turn of wire on the coil is like a single AC generator, so if you have 8,000 turns of wire, it's as though have have 8,000 AS generators producing a voltage in series, which all adds together, in the same respect that two 1.5 volt batteries in series gives you 3 volts, three give you 4.5 volts, etc. The number of little AC generators you have in series corresponds to the amount of wire, which corresponds to

The catch is that the number of winds on the coil is not the only factor that determines voltage and inductance. The output voltage and inductance are also effected by the core materials, and the voltage specifically is effected by magnetic strength and coil geometry, but that only means we can't compare pickups that are of a significantly different types. If you have two Stratocaster single coils with AlNiCo 5 pole pieces, or two P.A.F. pickups with identical dimensions, then nearly all of those additional factors are the same, and therefore cancel out on both sides of the equation. Chances are, you're probably comparing pickups of a given type to being with. So if you have two Strat pickups, and one has a DC resistance of 6.0k, and the other 6.5k, the inductance, and therefor the "hotness", will track closely with the difference in DC resistance. Also note that while DC resistance is linear as more wire is added to the coil, inductance rises exponentially, so the "hotness" difference between a 5.5k and 6.5k Strat pickup is smaller than 6.5k up to 7.5k, which is smaller than 7.5k to 8.5k, etc.

The major practical problem with associating DC resistance to the hotness of a pickup is that not all pickups are wound with the same wire gauge. Most all pickups are wound with 42AWG, but many pickups, such as Tele neck pickups, are wound with the finer 43AWG, and many high output humbuckers are wound with even finer 44AWG. The finer wire will show a higher DC resistance for the same length of wire. So if you're comparing two Strat pickups, and one is wound with 42AWG while the other is 43AWG, it's apples and oranges. Fortunately, that can be accounted for by converting the actual DC resistance of one wire gauge to the relative DC resistance of another. Then it's apples to apples again.

This PDF offers values for resistance per foot of these different guages of copper wire mwswire.com/wp-content/uploads/2016/10/techbook2016.pdf

Here is the good part:

There's only three values here that are needed 1659, 2143 and 2593 ohms, the nominal resistance for 42, 43 and 44 AWG. The min and max suggest the margin for error, although it's not apparent here the degree to which copper wire deviates from the nominal value.

Therefore...

To convert 42 AWG to 43 AWG equivalent, you multiply the resistance by

To convert 42 AWG to 44 AWG equivalent, you multiply the resistance by

To convert 43 AWG to 42 AWG equivalent, you multiply the resistance by

To convert 43 AWG to 44 AWG equivalent, you multiply the resistance by

To convert 44 AWG to 42 AWG equivalent, you multiply the resistance by

To convert 44 AWG to 43 AWG equivalent, you multiply the resistance by

One practical use of these conversions if determining just how much hotter an "overwound" 43 AWG bridge pickup is than it's 42 AWG normal wind neighbors. Take the Antiquity II for example, the "hot bridge" has a DC resistance of 10.08k with 43 AWG whereas the neck and middle have DC resistance of 6.44k with 42AWG. So what would the DC resistance be for the hot bridge if it were 42 AWG? 10.08k * 0.77 = 7.76k. Could the hot bridge actually be wound with 44AWG? If the "hot bridge" were wound with 44AWG, the 42AWG equivalent would be 6.4k, which is the DC resistance of the neck and middle pickups, but because we know the "hot bridge" has a much higher inductance than the neck and middle, and is in fact "hotter", it's not possible that 44AWG has been used.

The real tricky business might be determining what wire gauge a coil is wound with. The "default" is 42AWG for most all "vintage" Fender and Gibson pickups. In general, when a Fender single coil has a DC resistance over 8k ohms, the higher DC resistance suggests that it's bumped down to 43AWG. For a P.A.F. style humbucker, the cut off from 42AWG is somewhere between 9k and 10k ohms, as this is the point where the bobbin becomes "full" with 42 AWG, necessitating smaller 43AWG wire. The corresponding cutoff mark for 43AWG is harder to pin down, but if the DC resistance is over 15k ohms, odds are it's that even thinner 44AWG wire being used. In the case of P-90's, because they have such a large bobbin, most all are wound with 42AWG, despite reaching a DC resistances beyond 10k with just one coil.

If you're shopping for pickups, and all the pickup maker is offering are DC resistance values, these considerations and calculations can help you determine how their product compares to others, despite of the scant technical information provided.

When people say a pickup is "hot", it means two things: louder and darker. The darker part comes from the inductance, because a pickup is an LC low pass filter, and a higher inductance "L" means a lower pass. As for louder, every turn of wire on the coil is like a single AC generator, so if you have 8,000 turns of wire, it's as though have have 8,000 AS generators producing a voltage in series, which all adds together, in the same respect that two 1.5 volt batteries in series gives you 3 volts, three give you 4.5 volts, etc. The number of little AC generators you have in series corresponds to the amount of wire, which corresponds to

*DC resistance*(a critical caveat is that not every loop of wire produces the same voltage, the loops closer to the guitar string produce more voltage than those which are farther away).The catch is that the number of winds on the coil is not the only factor that determines voltage and inductance. The output voltage and inductance are also effected by the core materials, and the voltage specifically is effected by magnetic strength and coil geometry, but that only means we can't compare pickups that are of a significantly different types. If you have two Stratocaster single coils with AlNiCo 5 pole pieces, or two P.A.F. pickups with identical dimensions, then nearly all of those additional factors are the same, and therefore cancel out on both sides of the equation. Chances are, you're probably comparing pickups of a given type to being with. So if you have two Strat pickups, and one has a DC resistance of 6.0k, and the other 6.5k, the inductance, and therefor the "hotness", will track closely with the difference in DC resistance. Also note that while DC resistance is linear as more wire is added to the coil, inductance rises exponentially, so the "hotness" difference between a 5.5k and 6.5k Strat pickup is smaller than 6.5k up to 7.5k, which is smaller than 7.5k to 8.5k, etc.

The major practical problem with associating DC resistance to the hotness of a pickup is that not all pickups are wound with the same wire gauge. Most all pickups are wound with 42AWG, but many pickups, such as Tele neck pickups, are wound with the finer 43AWG, and many high output humbuckers are wound with even finer 44AWG. The finer wire will show a higher DC resistance for the same length of wire. So if you're comparing two Strat pickups, and one is wound with 42AWG while the other is 43AWG, it's apples and oranges. Fortunately, that can be accounted for by converting the actual DC resistance of one wire gauge to the relative DC resistance of another. Then it's apples to apples again.

This PDF offers values for resistance per foot of these different guages of copper wire mwswire.com/wp-content/uploads/2016/10/techbook2016.pdf

Here is the good part:

There's only three values here that are needed 1659, 2143 and 2593 ohms, the nominal resistance for 42, 43 and 44 AWG. The min and max suggest the margin for error, although it's not apparent here the degree to which copper wire deviates from the nominal value.

Therefore...

To convert 42 AWG to 43 AWG equivalent, you multiply the resistance by

**1.29**( 2143 / 1659 )To convert 42 AWG to 44 AWG equivalent, you multiply the resistance by

**1.56**( 2593 / 1659 )To convert 43 AWG to 42 AWG equivalent, you multiply the resistance by

**0.77**( 1659 / 2143 )To convert 43 AWG to 44 AWG equivalent, you multiply the resistance by

**1.21**( 2593 / 2143 )To convert 44 AWG to 42 AWG equivalent, you multiply the resistance by

**0.64**( 1659 / 2593 )To convert 44 AWG to 43 AWG equivalent, you multiply the resistance by

**0.83**( 2143 / 2593 )One practical use of these conversions if determining just how much hotter an "overwound" 43 AWG bridge pickup is than it's 42 AWG normal wind neighbors. Take the Antiquity II for example, the "hot bridge" has a DC resistance of 10.08k with 43 AWG whereas the neck and middle have DC resistance of 6.44k with 42AWG. So what would the DC resistance be for the hot bridge if it were 42 AWG? 10.08k * 0.77 = 7.76k. Could the hot bridge actually be wound with 44AWG? If the "hot bridge" were wound with 44AWG, the 42AWG equivalent would be 6.4k, which is the DC resistance of the neck and middle pickups, but because we know the "hot bridge" has a much higher inductance than the neck and middle, and is in fact "hotter", it's not possible that 44AWG has been used.

The real tricky business might be determining what wire gauge a coil is wound with. The "default" is 42AWG for most all "vintage" Fender and Gibson pickups. In general, when a Fender single coil has a DC resistance over 8k ohms, the higher DC resistance suggests that it's bumped down to 43AWG. For a P.A.F. style humbucker, the cut off from 42AWG is somewhere between 9k and 10k ohms, as this is the point where the bobbin becomes "full" with 42 AWG, necessitating smaller 43AWG wire. The corresponding cutoff mark for 43AWG is harder to pin down, but if the DC resistance is over 15k ohms, odds are it's that even thinner 44AWG wire being used. In the case of P-90's, because they have such a large bobbin, most all are wound with 42AWG, despite reaching a DC resistances beyond 10k with just one coil.

If you're shopping for pickups, and all the pickup maker is offering are DC resistance values, these considerations and calculations can help you determine how their product compares to others, despite of the scant technical information provided.