Well... why do you think I replaced the original coil of 1470 ohms with a 15.1 ohms? The field coil need 10-30 watts of power (source: Hentai user who made a few of these from scratch, see ProjectRyu thread).. .after you make the calculations you realize you need 1-2 amps at 12 volts... that's battery territory. The magnetic strenght is currents x turns in the coil... so making a coil with less turns with thicker wire means you can get same amgnet strenght with higher amps but also you need a lower voltage at the power source.
Hentai did not use any humbucking coils.
That sounds good except for a couple of things.
First, vintage Field Coil Speakers operate at a higher voltage because they were serving as the choke of its tube amp, with high DC voltage directly from the tube amp. That’s how they did it. Does that sound about right? Not pretending to be an expert here. So anything vintage or a vintage design will be like this.
Secondly, some people deep in the field feel that the higher voltage gives a better sound. I would love to go with the 12 V power supply battery because I use a batcap for 12V gear, which is like a very high performance battery meant for competition audio, that discharges as fast as a capacitor, but in this case fast discharge doesn’t matter so much since it is only to keep the field coil field constant.
Again, I’m no expert on this. Does that sound about right? Or am I off a bit here?
So if you want to go 12 V you can get Voxativ (?) Field Coil Speakers for tens of thousands of dollars. There are less expensive FC 12V speakers, probably only $3000-$5000 a pair.
Or you can roll your own and go that way. Whatever works I guess. But I think we are talking about getting a good high voltage supply for more vintage designs. But you are absolutely right, there are 12 V designs also.
Oh yeah, there are the Musical Affairs loudspeakers that require 12 V DC, but Hans the owner and brains And designer died and the company fell apart and they are scarce to find. Again, tens of thousands of dollars for a pair of loudspeakers.