I'm hoping someone else has had this problem before and can advise... I have a Sandberg VM4 with Nordstrand blades installed (PJ configuration). The pups sound great but the problem I have is when I play aggressively (hitting the strings harder) I get a popping noise, When I pluck a string hard the string strikes the pup and causes the loud "clack" sound. I can hear it in live recordings of the band. Should I put electrical tape on the pup or will that affect the sound too much? Keep lowering the pups until I can't cause it to happen? ???
Electrical tape won’t disturb the magnetic field at all, so it won’t change the tone, but … … that’s the right course of action.
Everything CTMullens wrote is correct. But here is just a thought…. When the pickups were installed, were the designated Hot and Ground wires terminated correctly, or may have they been reversed on both pickups. Just asking because I once needed to reverse the Hot and Ground of a Duncan QP jazz pickup, due to an out-of-phase condition with the MM-style bridge pickup. It was easier to swap those two wires than messing with the 4 wires of the MM. Anyway, when I used the Ground wire as Hot and Hot as ground, I noticed that the same exact thing happened - when string contacted the pole pieces, there was a *pop*. I then wound up setting those two wires back and rewired the MM pickup. Has something to do with the ground side of the pickup being hot and not playing well with the pole piece shield I think. I mention that both could be wired backwards since you don’t complain about phasing. Typically, with shielded pole pieces, there shouldn’t be any electrical pops when strings contact them - all should be grounded.
Part of the problem might be solvable by looking at how you could alter your technique to control the string excursion that’s causing the contact with the pole piece. You may not need to play any less aggressively just control it better.
In a pickup with shielding and grounded pole pieces, the shielding (and hence pole piece grounding) is sometimes done through the "ground" wire for the coil itself. This is unfortunate, since it means you can't flip the polarity of the coil without putting the shielding and pole pieces on the hot side of the circuit. At a minimum, this is a problem because the noise being picked up by the shielding and pole pieces is now going to your amp instead of to ground. This can also be a problem because you now have exposed conductive pole pieces in the hot side of your circuit, so anything touching them is going to make noise - especially the strings, since the strings are grounded - if a string touches a pole piece it creates a dead short across the pickup (and a very loud thud/click). So, yeah, it definitely makes sense to check - if the poles are connected to the side of the coil that's intended to be ground - you must have the wires routed correctly to ground and hot. Some pickups (including essentially all standard issue Fenders) have no internal shielding and the poles are not grounded at all, which eliminates the above scenario, but causes it's own problems - if a string touches an ungrounded piece of conductive material (ie a pole piece) it will thud. Really, the quietest configuration for pickups with exposed conductive pole pieces is to have at least some shielding on the pickup (strip of copper tape on the bottom as a minimum), and have the shielding and poles both connected to a separate wire that runs straight to a main ground point in the control cavity. Then you can route the coil wires to connect the pickup to your controls separately from the shielding and poles. Bonus points if you determine which end of the coil is the inside end (start end) and use that as the ground side of the coil.
I should add, extra extra bonus points for setting up your pickup height such that the strings don't contact the pickups at all, because even if things are properly grounded, a string hitting an exposed pole will still cause at least some minor noise just from the mechanical vibration of the pickup. Also, you can substitute "blade" for "pole" in any of this and it remains accurate.