Here's a comparison between the input and output transducers of a TAD pan, a new Accutronics pan and an old Accutronics reverb pan.
The input coil on the old Accutronics is not the original one.
The photo was taken while I was experimenting with different gauges of wire to wind the input coil to obtain an 8 Ohm coil (A-type) instead of the original 600 Ohm (E-type) coil.
The laminations are also a bit damaged from pulling them out with (the wrong kind of) pliers.
This doesn't take away from the fact that the used materials and dimensions clearly differ:
Another thing I noticed is that I read electrical continuity between the laminations (the metal plates/sheets that go through the coil) on the newer pans and not on the old pan.
If there's electrical continuity they could just as well have used a solid core I think.
The whole point of the laminations is to prevent eddy currents.
The laminations need to have some form of coating to prevent them conducting between one another to prevent them acting together like a solid core.
Eddy currents in a solid core vs a laminated core:
Here's a simulation someone posted over at another forum that shows the effect eddy currents have on the frequency response.
Although a simulation, I've also taken real life frequency responses of the same guitar pickup with and without eddy currents, by modifying the brass pickup cover, and those graphs very much resembled those in the simulated ones below.
In layman's terms: it causes a dip in the mid frequency range right before the resonance peak in the treble range. Overall it reduces treble content but the mid scoop can be clearly audible as well.
The lack of (high) mids in the newer pans is something I have seen mentioned by people describing why older pans sounded better.
Obviously this is only one (small) part of the overall mix of elements that make up the final tone or timbre.
No eddy currents:
Eddy currents effect:
Last edited: Feb 13, 2020 06:19:54