When it comes to humbucking guitar pickups, we were wondering whether there was a tonal difference between covered pickups and open coil pickups. A quick cruise through the Internet revealed that opinions vary. Some said there was a definite difference between open and covered pickups, while others said there was no difference. We decided to conduct our own experiment, and report the results in InSync.
We recorded a semi-hollowbody guitar with covered humbuckers and new strings to have a point of reference. After the recording, we removed the strings, popped the bridge pickup out, and removed the chrome cover being careful not to damage the windings. We replaced the pickup sans cover, put strings on, plugged into the same amp with the volumes set the same, and recorded using the same microphone.
The uncovered pickup, to our ears, had a brighter, more open sound than the same pickup with the cover in place. Just for fun, we switched to the neck pickup (which still had a cover), and in comparison to the uncovered bridge pickup, it had a nasal quality. Prior to removing the bridge pickup cover, we had never noticed a nasal tone when using the neck humbucker, but in comparison to the open coil’s clarity and brightness, it did sound inferior.
According to statements we’ve seen by pickup manufacturer/guru Seymour Duncan, there are differences between covered and uncovered pickups:
- Covers may cause feedback problems with high-powered amps
- The pickup’s magnetic field may be affected by the cover’s plating materials; brightness may be reduced by nickel, chrome, or gold plating
- Electrical interference may be picked up by uncovered pickup coils
- Covers may reduce 60-cycle hum
- A nickel-silver cover may have less capacitance, which can affect brightness
Now, we’re not suggesting that you rip the covers off your humbuckers. We are simply stating what our ears heard during our experiment. The good news is that pickups are easy to pop in and out of a guitar, as long as you don’t disconnect the wires, which requires soldering to remedy.
So if you feel frisky, try removing the cover from a humbucker and do an A/B comparison of the covered and uncovered tones. In our case, removing the cover from pickup we used involved breaking the solder that held the cover to the base of the pickup, and since we’ve decided to leave the bridge pickup uncovered, clearing out some of the wax potting that surrounded the coils.
As always, if you don’t feel comfortable doing work of this nature, please refer the job to a trusted guitar repair specialist.