Metal pup covers for looks only... or?

Just out of curiosity... do the nickel or brass covers on the HB pups make a sound difference, or are they just for looks? If they do make a sound difference... what is it?

Depends on who you talk to. Most quality nickel covers do not affect the sound at all. If they do, the will affect the treble a little (less treble), but again, very little. Most folks would be hard pressed to hear the difference, IMO.

I'm with Jeff on this one. The Brass covers affect the pup adversely from some of the stuff I've read. Seth Lover went with the German silver (nickel silber) because it didn't bother the magnetic field. Some people think it helps further buck the hum.

Luke

Thanks guys. There is an APH-1 listed on ebay with gold cover. I will pass then.

So even with higher about pups like the Custom series, JB and Distortion- the tone and output is pretty much the same? I like the look of nickel covers, but I always thought it would alter the tone.

The non-porous material that SD use for the Covers were specifically selected because it does not affect the tone of the pickup. The original pickup covers that Gibson used in the original PAF in the '50's were made out of pressed sheet metal that made them good conductors. Not good. The Humbucker was first designed to have a metal cover to help shield against external noise. It is connected to the outer shielding of the pickup lead wire via the base plate, which also acts like a shield. This way, the external noise can be trapped by the cover and routed to the ground. This method is highly effective, but there is one drawback: ''stray capacitance'' appears between the cover and the coil. On the structure of the humbucker, although unintended, the cover and the coils are laid out in such a way as to create a capacitor. The resulting unintensional capacitance is called ''stray capacitance'', and it is extremely small in value. In this situation, certain upper frequencies of the signal produced by the strings may leak from the coil to the cover and eventually go to the ground. The cover is acting as a tone filter, making the sound less bright. If we reverse this effect, removal of the cover may make the sound sharper and brighter. This is because the leak is stopped. All the high frequencies which were otherwise thrown out would come back to life. Players were abale to gain more clarity by removing the covers. That's why when Eric Clapton and Greg Allman took the covers off from their LP's pickups experienced significant amount of tone improvements. Countless other famous artist did the same thing. Even Page and Beck did the same after seeing Clapton do this.
Nowadays, modern covered humbuckers don't suffer anymore from high end loss because of the quality and type of non-conductor material used on making the covers. I, personally prefer covered humbuckers simply because to me, they give my Les Pauls more of the Vintage appeal. Specially now that the covers are made 100 times better than the old ones and does not affect tone anymore.