SweetDan wrote: ↑Mon Feb 26, 2018 12:36 pm
So, I was just reading about JD's new p'up, and I was curious about what effect you get from the different resistances on the two coils. What's the theory (or actual data) about that?
Thats a hard one...
Lets break it down a bit..
There is data, lots of it but in terms of tone all things are subjective and there is little or no correlation between that and hard data. Every guy I know who winds pickups or makes guitars keeps minute records of everything he does and how it affects the outcome. I'm no differant so without digging too deep into the physics of it here is what I have found and why I do things as I do.
A bobbin traditionally on a PAF style would have around 5000 turns of copper wire. That was what Gibson were aiming at as they wanted to match the 10000 turns they used as a guide for the P90 bobbins. Now back in the day the counters werent all that good and they would wind up bobbins and chuck all in a box and just grab two when they assembled the pup and off it went. The result of that is that there are not really two identical pups in terms of wind count or matching bobbins. The upshot of this is that as people have tried to examine why PAFs of old have that unique tone they have attributed some of that charm to wind count as well as aged pickups, wire coating, all sorts really. One thing for sure the most popular sounding pups had a slight mismatch on the turn count per bobbin. Not much but enough to make a difference.
Now what I have found is that by pushing that mismatch or bias as I prefer to call it you can get some really clear articulate pups going. Its one of the main things I play around with to get clarity and articulation. To my ears they seem to be less muddy and a have nice bright punchy highs. If you go too far you start to get that single coil quack without much of the p90 grunt so its a balance for me.
Typically I aim for a 5% mismatch. I would push that if I was asked to give over a decent coil split tone or wanted to add a bit of bite without going too hot. Conversely if I was aiming to get that screaming shrill metal tone then I would get the two bobbins as close in all manner as possible. Thats kind of why the 490, 498'S etc seem to be popular with the metal and thrash guys and not many others.. They are machine wound and identical bobbins...
You could write a whole book on this crap so I'll stop now. At least you know why I do like I do..
The theory is about inductance and how the field generated and eddies all interact. Its a mine field much as the acoustic I used to teach. Every thing you change affects everything else. In the real world its about what you know works and pushing that. The feel for it comes with doing it not just a bunch of data. The data helps me do it again more quickly with more consistent results. Thats all..