Humbucker - Brass vs.Nickel Silver vs. Copper underplate

[craggyisland]

Morning Folks.

another "niche within a niche" test i'm afraid.

Following on from the Brass vs. Nickel Silver test i carried out on a Telecaster neck pickup (Here) - we saw a big effect on the resonant peak when a cover was fitted - with "plated" Nickel silver covers behaving alot more like brass covers then "unplated" Nickel silver - and i attributed that to the copper under layer beneath the plating - but i was unable to prove this, because i dont have access to "uncoppered but plated" Telecaster covers.

BUT... i do have access to them in Humbuckers!

so here you go - exactly the same test - but a humbucker!

Brass behaves as we all expect i imagine - but this time - "Nickel silver W/Copper" (Red) is much closer to what I'd expect - the "Nickel Silver W/Out copper" and "Nickel Silver Unplated" both behave identically (Green and blue have overlaid each other)

So yeah - i think we can safely say that if your going for a plated cover, going without the copper underplate is "better" (or closer to uncovered atleast) - but the difference between a coppered, non-copper and unplated cover is so small, that your probably never going to hear the difference (considering most folks agree that nickel "has no effect on the pickups sound".

Whats strange though, is that this doesn't correspond with the Telecaster test (where coppered/plated had a much greater effect then unplated)

It is, slightly, academic (isn't all of this? ;-)) - because whilst non-coppered/plated covers are fairly common on humbuckers - I've never seen one for a Telecaster (where the standard would be brass anway in most cases) - but yeah, i liked the humbucker test - feels like your on firmer ground doesn't it?

[antigua]

Thanks for doing this test. I wouldn't know how to source identical covers with these various platings. 

I think its a little harder to compare humbucker covers directly to Tele covers, because humbuckers have steel pole pieces with their own significant eddy currents occurring at the same time, and the eddy current effects are different when you have humbucking. Ken Willmott showed kenwillmott.com/blog/wp-content/uploads/2016/11/Pickup_Cover_Geometry.pdf that with a humbucker you don't have to have a cut that extends to the bottom of the cover, it only has to extend from the pole piece(s) of one coil over to the other. I guess the eddy currents themselves hum buck? I'm not sure.

Also note that some of these 1dB differences with no load become even smaller, like 0.1dB, once there is a tone and volume pot load, so in situ, there's effectively zero difference. 

[craggyisland]

May 10, 2021 11:51:38 GMT -5 antigua said:

Thanks for doing this test. I wouldn't know how to source identical covers with these various platings. 

I think its a little harder to compare humbucker covers directly to Tele covers, because humbuckers have steel pole pieces with their own significant eddy currents occurring at the same time, and the eddy current effects are different when you have humbucking. Ken Willmott showed kenwillmott.com/blog/wp-content/uploads/2016/11/Pickup_Cover_Geometry.pdf that with a humbucker you don't have to have a cut that extends to the bottom of the cover, it only has to extend from the pole piece(s) of one coil over to the other. I guess the eddy currents themselves hum buck? I'm not sure.

Also note that some of these 1dB differences with no load become even smaller, like 0.1dB, once there is a tone and volume pot load, so in situ, there's effectively zero difference. 

Yeah man - near as I can tell, the difference between the different iterations of nickel cover (all in the same style - 6 hole) makes no difference with a humbucker - but there seems to be some credence to the unplated/no copper line of thought with teles (or anything with magnetic poles) - useless test comparing pickup to pickup, but interesting to see the effect of copper underplating. (Seems to not matter where we all thought it did, and does matter where we never considered it!... always the way eh?)

Suppose I'll have to make some uncoppered tele covers and see whats what.

Next test, for my own sanity - is to see how bases make a difference now - I know that brass vs. Nickel makes no difference with uncovered humbuckers, but I've some rough and ready tests with an eq that show differences when covers are fitted - so yeah, should keep me busy.