GilmourD
Burritotoneologist
Re: Questions about open humbucker cover.

Oh, if only you knew.Like your avatar.
Oh, if only you knew.Like your avatar.
Some people (myself for example) take our gear & tone very seriously, and we want to know, "why does this do that?".
And sometimes that means we expound upon it... even discuss it. And even discuss the "SCIENCE!" about it.
So what?
Maybe there should be a separate sub-forum for people who dig these subjects at an intricate level... I don't know.
But this ******** **** gets old.
My take? Never used open humbucker, but I have used covered vs uncovered Seth Lovers, and there is a difference. I would use the adjectives "tamer" and "more polite" for the covered (vs the uncovered).
Understanding eddy currents and electrostatic versus electromagnetic interference is practical information, and it does relate to the OP and later posts.
So we agree that the science is sound, why don't you prove that these effects are inaudible? Why should the onus be on me to prove that you can hear them?
Dead wrong, Chumly. You made the assertion - you provide the proof.
In an earlier thread, I had said that my view was that if a difference is under 1dB, it can't be heard, so the same rule could apply here; if the eddy current losses associated with a open top cover are under 1dB, they can't be heard. But Frank Falbo's view is that <1dB difference can be amplified with gain, so the 1dB rule would only apply to a squeaky clean, linear amplification. Whether or not there would be a loss in peak resonance more or less than 1dB depends on a handful of factors, but if you hold Frank's view that disortion brings out small differences, the odds increase that you would hear the difference in resonant damping in your particular setup.
What assertion? You still haven't specified.
Wrong again, Chumly.
Yes. I have 2 points on this matter, the first, same as I made in another thread. Under gain, with distortion and clipping characteristics, a small difference at the pickup can become noticeable in the electrical signal. But also it can manifest itself in the speaker cone and the air itself! In other words, if we were to compare a direct signal to the power/cabinet sound, even if the direct signal includes an IR of the same power amp and speaker cabinet, there are things that happen in the cabinet to multiply small pickup differences, mostly in the lower and midrange frequencies. With eddy currents we mostly consider them high frequency losses, so forgive me because technically I'm going off topic here:Good point here. Science often has to reconcile theory with practical real world applications, and this is a great example of how apparent discrepancies can surface. Guitar-amp-speaker can be a nonlinear and highly dynamic system, one which is different for just about every player. The ±1dB rule stands unchallenged. Yet it's not unreasonable to acknowledge that tiny differences at the pickup, while initially imperceptible, can still translate to noticeable tonal changes in the final sound.
What assertion? You still haven't specified.
Uh-oh, a question for the lab coat crowd. lol!
Technically, they "could" have an impact. But I think you'd have to be like Eric Johnson or Yngwie to hear it. I have a few Mojotone sets with the open covers. I think the biggest draw to them is that they are handy for people that like their pickup way close to the strings, but don't want to do the Dimebag "tape trick"
I also subscribe to the notion that ANY magnetically transparent cover DOES NOT affect the tone of the pickups.
but my covers would not stay on as they were cheap chrome plated copper ones and solder just kept coming away.