Pickups with mismatched coils?

[brianwenz Senior Member Find all posts View Profile Close brianwenz]

Re: Pickups with mismatched coils?

Hello Hello-
On a Gibson-style humbucker [2 bobbins side-to-side] the coils should be matched for max. humbucking effect. If one bobbin is 5K and the other is 5K the pickup will be as quiet as it can get, but if one coil is 5.5K and the other is 4.5K the noise will increase.
People started hearing differences in old humbuckers [PAF] and found that some of the "character" of the pickup was due to a slight mismatch in the D.C. res of the coils. [maybe one coil would be 4.3K and the other was closer to 5K....] This slight mismatch adds a little bet more "presence" or bight to the high end of the pickup. [it also makes them a little less "humbucking, though..]
Brian.

[sanrafael Tone Member Find all posts View Profile Close sanrafael]

Re: Pickups with mismatched coils?

Actually, you DO decrease the pickup's ability to cancel hum...so it will hum a little more with mismatched coils. It'll also be a little brighter and the highs will be extended a little. One coil will dominate the other and that dominating coil will give the pickup a very slight "single coil" edge to the tone.

This is because when the two out of phase coils are perfectly balanced they will cancel out any signal that they both pickup exactly the same way. Since the two coils are about 1" apart, they don't pick up all frequencies the same...but there's still alot of cancellation of upper harmonics with balanced humbuckers.

It's one reason why humbuckers are not as bright and open voiced as single coils...

Since both the magnets and the coils are out of phase, they both would respond to the same vibrating string in the same way. Thus if they could be in the same place, they would see the same signal, but as you say, the spacing causes differences. The fundamental and lower harmonics are long, and so the distance between the two coils matters little. The higher harmonics are short and are picked up with different phases and tend to cancel. This gives the less bright or harsh sound when compared to single coil pickups.

It seems to me that mismatching the coils is going to give you a real unpleasant surprise if you play with a lot of gain near a big power transformer. There are other ways to unbalance the signal while leaving the hum cancelation alone. The hum cancelation does not depend on the magnets, only on the cores and coils. For example, instead of using the single magnet used by most humbuckers, you can redesign the pickup to use a small magnet on the back of each core; then you can use different strength magnets on the cores for each coil. Or none at all on one coil for single coil sound.

[mongrollo Toneologist Find all posts View Profile Close mongrollo]

Re: Pickups with mismatched coils?

For example, instead of using the single magnet used by most humbuckers, you can redesign the pickup to use a small magnet on the back of each core; then you can use different strength magnets on the cores for each coil. Or none at all on one coil for single coil sound.

This sounds like a good idea...