Shielding coils and polepieces grounding, pickguard shielding.

[CarlosG]

Hi!
I was wondering why manufacturers don't ground magnets(sc)/polepieces(hb) and shield coils.
I thought it was a matter of saving money.
I took my FS-1.I grounded the magnets with a piece of thin wire, wrapped around the magnets.
I wound copper tape around the coil leaving a gap, this is supposed to minimize eddy currents.
Everything was grounded, connections checked.
I recorded samples.
To my surprise, the noise and interference did not decrease, they were still the same.
The sound of the FS-1 has changed a bit. Less glassy, ​​more midrange. Probably the capacitance caused by the grounded magnets and tape shifted the resonant peak.
The conclusion is that it makes no sense.
I'm also curious about pickguard shielding. I read somewhere, I think Chris Kinman talked about it, to leave a 5mm gap around the pickups. Do you think it has that much of an impact? Most pre-made pickguards have a shield to the very edge of the pickups.

 

[freefrog]

Hi!
I was wondering why manufacturers don't ground magnets(sc)/polepieces(hb) and shield coils.
I thought it was a matter of saving money.
I took my FS-1.I grounded the magnets with a piece of thin wire, wrapped around the magnets.
I wound copper tape around the coil leaving a gap, this is supposed to minimize eddy currents.
Everything was grounded, connections checked.
I recorded samples.
To my surprise, the noise and interference did not decrease, they were still the same.
The sound of the FS-1 has changed a bit. Less glassy, ​​more midrange. Probably the capacitance caused by the grounded magnets and tape shifted the resonant peak.
The conclusion is that it makes no sense.
I'm also curious about pickguard shielding. I read somewhere, I think Chris Kinman talked about it, to leave a 5mm gap around the pickups. Do you think it has that much of an impact? Most pre-made pickguards have a shield to the very edge of the pickups.

Yes, capacitance is susceptible to have increased but beside that, what is the material of your "thin wire"? If it's made of an alloy containing iron, it should rise a tiny wee bit the inductance - and alter the magnetic field. If it's made of copper, it might contribute to small amounts of eddy currents... Anything in contact with magnetic cores can affect measurements more than one would expect, IME.

Regarding shielded pickguards, any generalization would be a blanket statement. The actual composition and THICKNESS of the shielding materials are to take in account IME/IMHO.

Now and anyway, we're talking about subtle differences detectable with lab gear but not necessarily by ear. All depends on the full rig used, + its settings and on how the musician hears things, as usual. ;-)

 

[AdrianSD]

Hi!
I was wondering why manufacturers don't ground magnets(sc)/polepieces(hb) and shield coils.
I thought it was a matter of saving money.
I took my FS-1.I grounded the magnets with a piece of thin wire, wrapped around the magnets.
I wound copper tape around the coil leaving a gap, this is supposed to minimize eddy currents.
Everything was grounded, connections checked.
I recorded samples.
To my surprise, the noise and interference did not decrease, they were still the same.
The sound of the FS-1 has changed a bit. Less glassy, ​​more midrange. Probably the capacitance caused by the grounded magnets and tape shifted the resonant peak.
The conclusion is that it makes no sense.
I'm also curious about pickguard shielding. I read somewhere, I think Chris Kinman talked about it, to leave a 5mm gap around the pickups. Do you think it has that much of an impact? Most pre-made pickguards have a shield to the very edge of the pickups.

Very good experiment, thanks for taking the time to do it. The way I read your results: if grounding the coil shielding doesn't reduce the hum or interference, but affects the tone, it can be seen as just another mod.
On pickguard shielding: few years back I went and shielded the pickups and pot/switch cavities on my Jackson very thoroughly, then grounded it all, measured continuity and all that. To my disappointment it didn't reduce the hum when playing in that room. YMMV

 

[Seashore]

Several of the Duncans I've worked on have had ground wires between the shielding around the coils and the baseplate, which is then grounded to everything else via the pickup ground wire. Wouldn't the magnet and poles being in direct contact with the baseplate already have them grounded?

 

[CarlosG]

Several of the Duncans I've worked on have had ground wires between the shielding around the coils and the baseplate, which is then grounded to everything else via the pickup ground wire. Wouldn't the magnet and poles being in direct contact with the baseplate already have them grounded?

Trembuckers has coil shielding. SH doesn't. For me Trembuckers has less treble and more mids than SH, so shielding affects the sound slightly. I got a similar result with my FS-1.
In the case of a humbucker, the magnet is grounded from the base, but the pole pieces are grounded randomly, not all of them make contact.
I used to ground them manually, but now I know that it makes no sense because it has no effect on the noise.