Help with guitar noise please

[Tubetec]

'A magnetic shield that would efficiently divert external magnetic interfernce would have to completely enclose the pick-up, which would result in no signal from the strings.'
In that case how does the original Fender Tele lipstick neck pick-up work ?

 

[RoadrunnerOZ]

'A magnetic shield that would efficiently divert external magnetic interfernce would have to completely enclose the pick-up, which would result in no signal from the strings.'
In that case how does the original Fender Tele lipstick neck pick-up work ?

The metal case is chrome plated brass - originally these were made from surplus lipstick tubes by Danelectro and the coils were wound directly onto Alnico magnets without using a bobbin former. The magnetic field passes straight through the brass.

 

[abbey road d enfer]

There may be a confusion here.
The typical Telecaster bridge p/u is not a "lipstick". However, Roadrunner is correct in saying that the german silver case is magnetically very neutral, having a permeability equal to that of air.
There's been a lot of speculation about the possible effects on sound due to eddy currents, which led many musicians to open their humbuckers, hoping to make them clearer.
I have never witnessed any difference, but some say they can hear it. I believe it's due to confirmation bias.

 

[Newmarket]

It is real, though.
Any conductive object has a capacitance. Clouds have capacitance, it's how they carry charges.

Yes - it's real of course. What I am questioning is its relevance here wrt the OP's understanding wrt "Capacitive Screening" when capacitive coupling is really a part of the 'problem' and that is overcome by bonding the player to the guitar/ground/earth.

This capacitance is between body and the rest of the universe. Actually its a sum of all the discrete capacitances, between the body and the walls, between teh body and the electric wiring, between the body and whatever appliance in the room, dominated by capacitance between body and earth.

The body itself is not the source of noise. The body is an armature that defines two dominant capacitive pathes. One between the actual source of noise (in most cases the electrical wiring, and another between the body and the equipment that is subject to the resultant electrostatic field.
Touching a grounded part makes the body equipotential with it, so it doesn't radiate.
The body is a "secondary source", as in the Huygens-Fresnel principle.

Yes. It's a "secondary source" so that is a source but not the origin of the noise energy itself.

 

[Newmarket]

The skin of the human body is one plate of a capacitor, the surface of the earth is another (or anything close by that has a conductive skin). We earth houses with a ground-rod hammered into the earth and connected to the Earth/Neutral bus at the incoming power switchboard otherwise mains earth could be at dangerous voltages compared to local ground.

Worth noting that there are several earthing (or not) schemes used and enforced depending on the territory and individual circumstances. eg TN-S; TN-C-S; TT ; IT. There is some debate about the preferred system in various use cases.
fwiw in the UK TN-C-S is the standard residential scheme but in some circumstances eg isolated locations a TT scheme might be implemented with the installing electrician installing earth rods/plates as required to meet the legal standards.

https://electricalapprentice.co.uk/an-introduction-to-earthing-and-bonding/

 

[13engrsapper]

There has been some work on that.
The JEDEC human body model testing spec uses 100pF to local ground reference in series with 1k5 Ohms as a simplified model.

How that applies in a macro setting (when not specifically using that model to test device ESD susceptibility) is not clear to me.
Presumably standing barefoot on a concrete slab which is in contact with the ground would be a different situation than wearing rubber soled shoes on the second floor of a wooden building.

I am nothing more than a 100pF cap with a high ESR. I think I can wrangle some sort of t-shirt out of this thought.

 

[Newmarket]

I am nothing more than a 100pF cap with a high ESR. I think I can wrangle some sort of t-shirt out of this thought.

Let's hope the debate doesn't become polarised

 

[dai h.]

here are two interesting pages with somebody sharing results of their experimentation (includes measurements) with shielding (differences with slits in the pickguard shield and gaps for a directly applied shield) :

https://alltubepreamp.blog.fc2.com/blog-entry-172.html

https://alltubepreamp.blog.fc2.com/blog-entry-173.html

(these are in Japanese, so for non-speakers: )

https://www.deepl.com/translator

https://translate.google.com/

(IMO deepl seems quite good but I guess you can't do the whole page as on google translate)

(couple thoughts that sprung to mind, 1) is the difference something that can't be made up with EQ(i.e. turning up the treble some more on the amp), and 2) does distortion make a difference?))

 

[abbey road d enfer]

https://alltubepreamp.blog.fc2.com/blog-entry-172.html

https://alltubepreamp.blog.fc2.com/blog-entry-173.html

It is clear that having a conductor in the vicinity of a pick-up results in damping, particularly if it is arranged as a shorted turn.
I can't see if the tinsel wrapped around the SC p/u is shorted or not.

 

[RoadrunnerOZ]

It would seem that in the instances of using heavy base plate or a shorted thick wire loop or foil directly around the pickup there are discernible losses, whereas using thin foil the as a base or cavity shield losses are marginal - less than measurable if a slit is used to break the current. A fine slit made with an exacto knife is all that’s required after foiling an enclosure or pick guard

 

[RoadrunnerOZ]

couple thoughts that sprung to mind, 1) is the difference something that can't be made up with EQ(i.e. turning up the treble some more on the amp), and 2) does distortion make a difference?))

For shielding the copper foil tape i use is 0.036mm unlike the 0.2mm thin foil used in the in the thick/thin plate bottom comparisons and as such has even less of an effect due to eddy currents. The overall worst dulling effect seems to be if you have a shorted turn around and very close to the pickup (not the best thing to do) or a thick cavity/base plate or an uninterrupted ‘loop’ pick guard shield. The losses also appear smoothly tapered and at a loss of less than 1dB at peak for the sensible shield approaches, some not even measurable, if anyone thinks they can hear that then it’s time to start looking seriously at snake oil guitar cables or getting into ridiculously expensive hi-fi systems with $1000/foot cables.
If the shielding is done properly there should be no need to make-up with EQ for any losses.