Do you actually mean 2 core (as in 2 cores plus braid/earth) or just the single conductor that most vintage type humbuckers had (single plus earthed braid)
I ask because if you use the single conductor and reverse the hot and earth connections you will make the pickup casing live and it will buzz/add noise
I haven't seen any proper 2 conductor wiring on any BKP Humbuckers that I have had but I'm not saying it's not available
That's just cleared something up for me!
I don't bother with phase/coil-tap etc on humbuckers, I tried it years ago and I didn't like it at the time.
But on tele pickups, I want the series/parallel option on a four-way switch (and also, but less so, a phase switch sometimes) and so I've learnt about the "I need an extra wire" to earth the neck pickup's cover separately...
Ever since I learnt it, it's had me wondering why you don't get this "pickup casing live" issue on humbuckers when you switch phase - obviously you do! :lol:
Many thanks :D