Zhangliqun
Questionologist
Is F-spacing necessary? Sometimes, yes.
There actually seems to be 3 different spacings for humbuckers, not just two. Guitar Jones sells pickup parts in these three different spacings, and they are (drum roll).....
53 mm (F-spaced)
50 mm ("normal spaced")
49.2 mm (G-spaced, G for "Gibson", or pretty much vintage)
My experience in winding pickups with all 3 spacings is that a 50 mm will work fine in the bridge of any F-spaced guitar, IF, and ONLY IF......the pickup mount holes in the pickguard or the rout cavity in the wood (or however the pickup is lined up on your particular guitar) is dead-on.
Even if you have just a little sliver of the pole visible outside both E-strings, it will sound the same as if all 6 poles are lined up dead-center. Because the bridge pickup can get only primarily higher frequencies off the string so close to the bridge, the E poles still pick those up just fine if at least SOME of the E pole is under the string.
If a 50 mm pickup itself isn't lined up right in the pickup cavity, then you might run into some problems because one or the other E-string won't be sitting over any part of the E pole. If this is a consistent problem with your guitar, 53 mm (F-spacing) is the way to go.
49.2 mm is where you run into problems. A difference of 0.8 mm doesn't sound like much, but it's enough to guarantee that one of the E's won't have any part of a pole directly under it, which means one of the E's will be a little weak.
The neck position is a different story. You really need to have the strings lined up as close to the center of the pole as you can because the neck pu needs to read those lows and low mids as clear and strong as possible, especially on the high strings. 49.2 mm is ideal there, 50 mm will do the trick. (I actually prefer the 50 mm in the neck because I like the lower strings to be a little off-center so they're not boomy.) Don't bother with F-spacing.
As for which Duncans are 49.2 mm and which are 50 mm, don't ask me. For all I know, they don't even have two different vintage sizes. I only know about the sizes for the parts I use.
There actually seems to be 3 different spacings for humbuckers, not just two. Guitar Jones sells pickup parts in these three different spacings, and they are (drum roll).....
53 mm (F-spaced)
50 mm ("normal spaced")
49.2 mm (G-spaced, G for "Gibson", or pretty much vintage)
My experience in winding pickups with all 3 spacings is that a 50 mm will work fine in the bridge of any F-spaced guitar, IF, and ONLY IF......the pickup mount holes in the pickguard or the rout cavity in the wood (or however the pickup is lined up on your particular guitar) is dead-on.
Even if you have just a little sliver of the pole visible outside both E-strings, it will sound the same as if all 6 poles are lined up dead-center. Because the bridge pickup can get only primarily higher frequencies off the string so close to the bridge, the E poles still pick those up just fine if at least SOME of the E pole is under the string.
If a 50 mm pickup itself isn't lined up right in the pickup cavity, then you might run into some problems because one or the other E-string won't be sitting over any part of the E pole. If this is a consistent problem with your guitar, 53 mm (F-spacing) is the way to go.
49.2 mm is where you run into problems. A difference of 0.8 mm doesn't sound like much, but it's enough to guarantee that one of the E's won't have any part of a pole directly under it, which means one of the E's will be a little weak.
The neck position is a different story. You really need to have the strings lined up as close to the center of the pole as you can because the neck pu needs to read those lows and low mids as clear and strong as possible, especially on the high strings. 49.2 mm is ideal there, 50 mm will do the trick. (I actually prefer the 50 mm in the neck because I like the lower strings to be a little off-center so they're not boomy.) Don't bother with F-spacing.
As for which Duncans are 49.2 mm and which are 50 mm, don't ask me. For all I know, they don't even have two different vintage sizes. I only know about the sizes for the parts I use.
