humbucker cover question

[gimmieinfo]

I bought a set of PAF types in zebra and i have covers that fit them. I wasn't going to put the covers on unless i found the pickups were bright enough that i thought they wouldn't dull the tone. They ARE nickel silver too, so even if they did it would be very minor. Anyways, i threw them on w/o soldering or potting just to see how it sounds and they sound just fine. no dulling effect. However, they do go microphonic if i use enough gain and while i don't use that much too often i'd still like to eliminate that potential issue, especially live where it could be rather embarrassing. So heres the question.... if i solder them on and pot the covers, (coils are already potted and taped) will that affect the tone? last thing i need is any dulling effect in which case i'd just leave them as is and deal with the squeal.

 

[Supernautilus]

Securing the covers won't affect the tone. Potting might a little, but personally I wouldn't bother. I've attached a few covers to open coil humbuckers and I've never had a problem. Just make sure they are on nice and tight. You can even take some paraffin wax and drip a little on the top of the coils before you put the cover on. Or else you use a strip of double sided tape. For added peace of mind, you can also flip them upside down when you're done and heat them with a good strong hair dryer, allowing any internal wax to melt and reform as they cool. That should help stop against the cover vibrating.

 

[freefrog]

Unless it's made of plastic or wood, any cover will introduce Foucault currents (eddy currents) having an influence on attack (slightly slowered and weakened) and high frequencies (a wee bit diminished). Through some rigs and to some ears, it doesn't make significant differences. Other rigs and people are more sensitive to this effect.

Some covers are worse or better than others, too.

How to avoid eddy currents? By avoiding metal covers (and baseplates) but also by using laminated components, like in transformers...

Adapted to covers, this concept of lamination gives the idea shared by Ken Wilmot: https://kenwillmott.com/blog/archives/246

FWIW, here is the effect of a cover on the electrically induced resonant peaks of an humbucker and on the speed of its attack. Horizontal scale is linear. Vertical scale shows increments of 0.5dB.

 

[gimmieinfo]

Securing the covers won't affect the tone. Potting might a little, but personally I wouldn't bother. I've attached a few covers to open coil humbuckers and I've never had a problem. Just make sure they are on nice and tight. You can even take some paraffin wax and drip a little on the top of the coils before you put the cover on. Or else you use a strip of double sided tape. For added peace of mind, you can also flip them upside down when you're done and heat them with a good strong hair dryer, allowing any internal wax to melt and reform as they cool. That should help stop against the cover vibrating.

Have you done it? I mean, played a set w/covers just pushed on then later soldered and/or potted?

 

[gimmieinfo]

Unless it's made of plastic or wood, any cover will introduce Foucault currents (eddy currents) having an influence on attack (slightly slowered and weakened) and high frequencies (a wee bit diminished). Through some rigs and to some ears, it doesn't make significant differences. Other rigs and people are more sensitive to this effect.

Some covers are worse or better than others, too.

How to avoid eddy currents? By avoiding metal covers (and baseplates) but also by using laminated components, like in transformers...

Adapted to covers, this concept of lamination gives the idea shared by Ken Wilmot: https://kenwillmott.com/blog/archives/246

FWIW, here is the effect of a cover on the electrically induced resonant peaks of an humbucker and on the speed of its attack. Horizontal scale is linear. Vertical scale shows increments of 0.5dB.

yes, i know but like i said i put them on and heard little to no difference so that not what i'm asking. What i'm asking is since they are just pushed on and not soldered or potted, will potting and soldering them change the tone vs just pushed on?

 

[freefrog]

yes, i know but like i said i put them on and heard little to no difference so that not what i'm asking. What i'm asking is since they are just pushed on and not soldered or potted, will potting and soldering them change the tone vs just pushed on?

The post that you quote was intentionally a general contribution, meant to be shared with the whole community.

That said, an answer to your question was actually embedded in it.

As soon as some conductive material forms a closed loop around / above / under coils and parallel to their wire, eddy currents appear, as explained by Ken Wilmott in the link that I've shared.

But any solder junction between covers and baseplates is perpendicular to coil wire. So, no, logically, it shouldn't aggravate Foucault currents already present.

Potting pickups under covers shouldn't either alter the electrical specs of already potted coils, BTW - unless the kind of wax used would be highly capacitive because of some added component. If you want to be sure, check the capacitance of your wax with a lab meter...