Noisebusters — the Movie

Things have moved on — we have to move with the times

From mmmmmm to zzzzzzzzz.

This pickup sounds great, but everyone wants to get into the action.

So, these things sound great, but have a real problem with buzz, the number one culprit being mains hum.

Here’s a close up of the signal this pickup generates when there is nothing else going on.

That’s a lovely trace of some mains hum, with a decent dollop of 100Hz on top for good measure.

Confession Time

I am old enough to remember the times when to avoid too much noise pickup while playing, the trick was to point the guitar in the right direction, as the coils are technically directional.

In the intervening 30 years since I started playing, and the 80 years since the device was invented, the electromagnetic environment has become a little more busy, and what worked formerly is no longer good enough.

As we will hear later in the recordings, there are certainly more mains hum sources numerically each year, though the strength of their emissions is not necessarily higher or lower.

What does seems to be more prevalent is Radio Frequency noise — mobile phones are a big emitter. And there now seems to be no place to hide from mains hum.

So, things need to change.

Solution: Shielding

Single-coil buzzkill: the why and how of electric guitar shielding. | stewmac.com

Mod Garage: How to Shield Single-Coil Pickups

Guitar Shielding FAQ

So, let’s give it a whirl

The procedure is: encase the coil in a grounded copper jacket and this should address most of your low frequency RF problems.

The tape is a copper with a conductive glue on the back so wrapping a layer of that should produce a nice high conductance shield around the coil.

The pickup — with cap removed.

It’s prudent to apply some insulation — the wires are coated, of course but a little protection is sensible.

This is the copper tape with conductive glue that will form the shielding.

Shield applied!

At this point the signal from the pickup now looks like this,

Mains hum may be gone, but it’s hard to tell with all that new RF interference.

One should not be surprised that attaching a lump of metal to the outside of your pickup without grounding it would attract more RF interference. By the way, it’s the same deal when you put thumb on the tip of the guitar plug, in that case it seems humans are good at channelling mains hum…

Ground your shields, or re-name them aerials, your choice…

This is the final result of the pickup. Hum is banished.

It’s not a failure that the RF is completely banished, as I never expected that to work 100% — remember the coil is not even in fully enclosed in a Faraday cage, and so some higher frequencies will always get in.

Faraday cage - Wikipedia

The final result — good first attempt, even if I say so myself.

Finally, here’s a nice soothing video of the effect on the guitar output prior to the procedure

hehe

It’s not easy to tell the net effect from the video, as I have had to adjust the audio levels for pedagogical purposes, so that the change in the quality of the noise is conveyed.

However let me assure you, the effect plugging that pickup in is an eerie silence, as the slight murmur the ear is used to hearing is simply not perceivable.