So the difference is covered vs uncovered? Except I had the same experience with chrome/nickel vs gold. And my experience was gold covers were just slightly brighter than uncovered. (FWIW I always set the screws the same way before playing, just slightly above the bobbin, which is sticking up on uncovered and slightly below the cover when covered. I run neck screws horizontally like - - - - - - and bridge screws like the PAF patent \ / \ / \ / )
Wasn't saying it necessarily
was covered vs not, simply brainstorming to think of anything besides plating or wiring that might account for it.
And I did say that for gold vs chrome, the adjustment aspect wouldn't apply.
Maybe it is indeed the plating itself. Gold has unique properties. Perhaps eliminating eddy currents is one of them.
Don't know whether that's been studied; I imagine it probably has at some point.
Still, gold covers have been around so long, you'd expect a difference would be widely recognized by now.
Then again, when it comes to subtleties of tone there's very little that all players will agree on.
Even today there are some who maintain that good quality covers don't affect the sound at all.
Personally, I've heard enough to convince me they definitely do.
It's an interesting subject anyway.
I don't have any frame of reference for this myself - my only gold pickup swaps so far have already had covers.
Got a gold Brobucker for bridge position on my Moderne and a BKP Rebel Yell set in gold for one of the Explorers.
Been thinking about new humbuckers for an SG Custom copy lately, though.
Would be using pickups from my parts boxes and almost certainly want to keep the classic look.
So installing some gold covers might be in my future.