ASK- HBS – Lap Steel – Electronic Buzz on All Amp Channels

Question

Hi HBS,

I have a new Chinese lap steel P90 single-coil pickup, with volume and tone knobs. I’m new to electronics, and I’m not sure of pot resistance. I have a new guitar cable and spark amp but I get an electronic buzz on all amp channels on the lap steel through the tone pot. If I touch any metal on the guitar or cord plugs or turn off the tone pot, the noise stops. Should there be a bridge ground? There’s no problem with acoustics, so I assume it’s from coil or wiring in the lap steel. High gain or metal channel on my amp really amplifies the hum.

Thanks,

James

Answer

Hello James, thank you for the great question. Unfortunately, a persistent buzzing sound on all channels is very common with P90s and all single-coil pickups. It’s the reason we have humbuckers, which eliminate the buzzing sound, but many people prefer the clarity offered by single coils, so they put up with it. Some people will use a noise gate to eliminate the sound when you are not playing.

It’s noisy because the single-coil and magnet create a rudimentary antenna that picks up radio frequency noise in the air around the guitar. This noise is then sent through the electronics to the amplifier. The sound goes away when you touch the metal because your body acts like a giant shield that absorbs the noise and sends it to the ground when you touch the metal. If your guitar (lap steel) was wired incorrectly, the noise would get louder when you touch the guitar.

It also gets quiet when you turn down the tone because doing so allows high-end frequencies to escape to the ground, and much of the buzzing sound you hear contains higher frequencies.

Some things you can try

• You can try moving to another part of the house. Some areas have higher concentrations of interference. Often, you can change the amount of noise you hear just by changing your body position.
• Look for items in the area that cause interference and eliminate them. Items that can cause noise include microwave ovens, dimmable lights (including touch lamps), fish tank pumps, fans, air conditioners, television sets, neon lights, and many other things.
• You can try shielding. We have several articles describing how to shield your guitar. This process may reduce noise, but it will be a lot of work for a minimal improvement.
• Since you probably play the lap steel in a sitting position, you can try to run a wire that contacts your body and the metal on the guitar at all times. It’s clumsy and might attract strange looks from the audience at a show, but it can work.
• You can swap out the P90 pickup for a miniature humbucker that fits in the same space. This method is likely your best option for permanently eliminating the noise while still getting a good tone from your guitar. If the noise is preventing you from playing, this is the solution we recommend.

Thanks again for the question. We hope this answer gets you closer to a solution.