This is an answer to a customer regarding the number of winds on the pickup:
"Thanks for asking about the number of winds. There are different views how to look at it - pragmatic, economic, electronic and sound to name some.
The pragmatic.- I have a lot of thicker wire from the early days left on stock. The bobbins fit less winds of thicker diameters.
The economic view.- It's faster putting 3000 instead of 8000 winds; plus, it uses up the otherwise useless wire on stock. The trigger was an industrial competitor, who imports copies from China with only "2k" or "4k". People even believe it's resistance, not turns and the importer doesn't seem to have an interest in putting it right.
The electronics.- More windings, more electric output. But we are talking of milliVolts and people use amps anyway. There's a dial on it that does the trick for "hot" or "underwound" alike. The problem starts, when people think, more is better. Look at society and see the results. Another thing is, that a thinner wire gives more compact coils that are less prone to microphonic effects. Anyways, against the believe, some people like microphonics. Including myself.
Sound.- My favourite view. We only perceive the vibes of air and interprete as sound. For me, psychacoustic perception means, that we - each of us in a personal way - have expectations which are met or not, wrapped in a bunch of influencing factors like the instrument, the pickup position, the PA equipment, the musician and what music he makes in which setup. As an example, I heard my pickups sound like blues, rock, jazz and acoustic.
What influences more is the footprint. Broader coils pick up more of the string vibes. On one hand, that transports the instrument's harmony; the other side is, that when being played at high gain and fuzz, the sound gets too much of everything. The small footprint of the Flatpup Slim single coil make it an allrounder with more mids, recommended for distorted sound. While I prefer to put the "classic" in neck position, the "Slim" also feels great at the bridge.
So, what should one choose? Pragmatically, the ones that are available. I will work full time in a hospital, sparing less time to build pickups. But those I build are made with pleasure.
Good luck in 2019 and happiness! Elmar