ampage Tube Amps / Music Electronics	For current discussions, please visit Music Electronics Forum.

ampage archive

Vintage threads from the first ten years

previous: Antidote I am using a SD Custom custom humbu... -- 10/6/1999 11:33 PM

Re: Hum from humbucker?

10/8/1999 8:59 AM
anonymous	Re: Hum from humbucker? I had a quick look at the SD Tone chart pages. The Custom-Custom has an AlNiCo2 bar magnet underneath the coils. This is the cause for the hum since AlNiCo has a high permeability and works - so to say as - a bridge for external magnetic field lines. They flow through the core of the first coil, then through the magnet and finally in opposite direction through the second coil. In this case hum adds due to the bar magnet and the humbucking effect is reduced. The Cool Rails have ceramic magnets under the coils. The permeability of ceramic is near that of vacuum and thus the external field lines flow through both coils in the same direction and hum cancels most effectively. I was really disappointed when I realised it, that nobody of the pickup gurus (SD, DiMarzio, etc.) spends a word on the noise level of their pickups. It's impossible to find a brighter (PAF style) humbucker with a ceramic magnet. Somebody who exchanged the AlNiCo bar magnets of an SD Jeff Beck and a Trembucker '59 against ceramic......

10/8/1999 8:59 AM

anonymous

Re: Hum from humbucker?

I had a quick look at the SD Tone chart pages.
The Custom-Custom has an AlNiCo2 bar magnet
underneath the coils. This is the cause for the hum
since AlNiCo has a high permeability and works - so to
say as - a bridge for external magnetic field lines. They flow through the core of the first coil, then through the
magnet and finally in opposite direction through the
second coil. In this case hum adds due to the bar magnet
and the humbucking effect is reduced.

The Cool Rails have ceramic magnets under the coils.
The permeability of ceramic is near that of vacuum and
thus the external field lines flow through both coils
in the same direction and hum cancels most effectively.

I was really disappointed when I realised it, that nobody
of the pickup gurus (SD, DiMarzio, etc.) spends a word on the noise level of their pickups. It's impossible to
find a brighter (PAF style) humbucker with a ceramic magnet.

Somebody who exchanged the AlNiCo bar magnets of an SD Jeff
Beck and a Trembucker '59 against ceramic......