ELECTRIC GUITAR SHIELDING
All the cavities of the circuits and pickups must be shielded and grounded using a special conductive paint or copper shielding foil that are easily available on the market.
The purpose of the shielding is to protect the components from external interference by using conductive materials that cover the circuit compartment and the pickup compartments.
For this reason, the shielded surface must be subsequently grounded with a dedicated cable, otherwise there will be no shielding effect.
The most effective shielding material is copper shielding foil, followed by conductive paint, two coats of which correspond to 80% of the shielding of the copper foil.
Aluminium foil is equivalent to copper foil but is more difficult to seal for grounding.
The best shielding available is the use of shielded cables for all signal cables. Above all, it will ensure that you keep all signal connections as quiet as possible and as bare as possible within the shielded cable.
All masses must be tinned with a “star” configuration on the housing of the volume pot and then sorted with a single output wire to the jack.
This arrangement is often recommended to eliminate so-called "ground rings".
A ground loop occurs when two components of a circuit (e.g. two potentiometers) are connected twice to ground, for example with a cable that connects them or through shielding.
The "star" type layout gives the circuit a very tidy appearance and is absolutely recommended. However, it should be noted that in the passive circuit of a guitar there can be no ground rings, which are to be found in more complex circuits such as tube amplifiers.
REDUCING THE HUMMING OF SINGLE COILS
If you are using the phase/counterphase option, it should be remembered that in this type of signal, circuit and ground are reversed. If you are using a single conductor + shielded cable the signal will therefore NOT be shielded.
In this case, I recommend the use of a two-wire cable and a sheath.
A good way to shield single coils is covering the coil with adhesive copper foil by connecting the shield to ground.
Another method is to coat the inside of the single coil pickup cover with conductive paint and then ground it. This method offers a three-dimensional shielding of the single coil protecting it from interference both on the side and on the top where the poles are exposed.