Ungrounded telecaster neck pickup cover

[brm]

Greetings,
I have a classic 50's telecaster (MIM) with stock pickups. I added a steel base plate to the bridge pickup. This seemed to affect the tone some. I also separated the ground on the neck pickup cover and added the separate ground in order to hook up the 4 way switch mod. adding series as an option. I have been fooling around with different wiring possibilities and in doing so I left the extra ground from the neck pickup cover disconnected. I notice that the pickup has more clarity with the cover disconnected. I have not played the guitar real loud and the wiring is hanging out of the control cavity at this point (no shielding whatsoever), but I don't seem to notice much difference as far as hum goes when I have the cover grounded or not. I don't have real bad hum. Has anyone left the pickup cover on and ungrounded before? Have you noticed any difference in tone? By leaving the cover in place but ungrounded is there any benefit as far as shielding goes.
Thanks for any input.

[David Schwab]

This is interesting. The only thing I can think of might be that having the cover on the same ground connection as the coil might be raising the capacitance of the pickup.

Cover do have a dulling effect on the tone, especially if they are made from brass and are too thick. The reason for this has nothing to do with interference of the magnetic field, but is actually from the formation of small eddy currents on the surface of the cover.

Grounding the cover should be done for noise reduction. I've not heard of grounding the cover causing tone loss.

Does it still do it if you run a separate ground wire from the cover?