Why Are Your New LED Bulbs Buzzing and How Do I Fix It?

You’ve installed beautiful new LED filament bulbs, expecting silent, perfect light. Instead, you hear a constant, annoying buzzing sound that makes a high-end space feel cheap and irritating.

A buzzing sound from an LED filament bulb is almost always caused by a micro-vibration in the bulb's internal driver, triggered by an incompatible signal from an old-style wall dimmer. Upgrading to a modern LED-compatible dimmer is the most effective solution.

I’ll never forget the call I got from Jacky, an excellent buyer for a US-based electrical distributor. He had a major crisis. He supplied thousands of our dimmable LED filament bulbs for a chain of luxury day spas. The goal was a serene, silent, and peaceful atmosphere. But when the dimmers were engaged, a faint but persistent buzz filled every treatment room. The spa owner was furious, saying it sounded like a "room full of mosquitos" and completely shattered the zen-like environment they were selling to their customers. Jacky was caught in the middle, with his client blaming our bulbs. I calmly asked him one simple question: "What model of dimmer did the contractor install?" As soon as he told me it was a standard, entry-level TRIAC dimmer, I knew exactly what the problem was. The bulbs weren't faulty; they were simply being fed a "dirty" power signal they were not designed to handle.

Is My Wall Dimmer Causing the Buzzing Sound?

You bought "dimmable" bulbs, but they buzz when you dim them. You're starting to wonder if the problem is not the bulb you just bought, but the dimmer switch that's been on your wall for years.

Yes, the wall dimmer is the number one cause of buzzing. Old dimmers designed for incandescent bulbs chop up the power wave harshly, causing the sophisticated electronics inside your LED bulb to vibrate and create an audible hum.

This is the most critical concept to understand when diagnosing a buzzing LED. The technology inside the dimmer switch must be compatible with the technology inside the bulb's driver. They need to speak the same language. For decades, there was only one type of bulb, so there was only one type of dimmer. Now, with LEDs, the game has completely changed.

The Old Technology: Leading-Edge (TRIAC) Dimmers

These are the most common and least expensive dimmers, found in millions of homes and buildings. They were designed for one thing: dimming simple, high-power incandescent bulbs. An incandescent is just a dumb resistor—a wire that gets hot. To dim it, TRIAC dimmers¹ use a crude but effective method: they chop off the front part of the AC electrical wave. The more they chop, the less power the bulb gets, and the dimmer it becomes. This "leading-edge" chopping creates a very abrupt, jagged electrical signal. An old incandescent bulb doesn't care. But an LED does.

Why TRIAC Dimmers Make LEDs Buzz

An LED bulb is not a simple resistor; it's a small computer. Inside is an electronic "driver" that takes high-voltage AC power and converts it to the low-voltage DC power the LED chips need. When this driver receives the harsh, chopped-up signal from a TRIAC dimmer, its internal components—particularly a coil of wire called an inductor—can be forced to vibrate rapidly. This physical vibration is what you hear as a 60Hz or 120Hz buzz.

The Modern Solution: Trailing-Edge (ELV) Dimmers

Modern dimmers, often called ELV (Electronic Low Voltage) or reverse-phase dimmers, were engineered specifically for sensitive electronic loads like LEDs. Instead of crudely chopping the front of the power wave, they smoothly cut off the back end, or "trailing-edge." This method is far gentler on the bulb's driver and eliminates the electrical conflict that causes vibrations. The result is smooth, silent, and flicker-free dimming. Upgrading to a trailing-edge dimmer is the most reliable way to solve buzzing problems in a dimmable system.

For Jacky's day spa project, the solution was clear. They replaced a few dimmers in a test room with modern ELV models. The buzzing disappeared completely. The client was satisfied, and they moved forward with replacing all the dimmers in the facility.

Could a 'Cheap' Bulb Driver Be the Real Culprit?

You've upgraded to an expensive LED dimmer, but some of your bulbs are still making a slight buzzing sound. You're frustrated because you thought you solved the problem, but the noise persists.

Yes. Even with a perfect dimmer, a low-quality bulb driver can still buzz. The components inside a cheap driver are often poorly made and not secured properly, making them prone to vibrating no matter what signal they receive.

This is where the quality of the bulb manufacturer becomes paramount. A supplier who cuts corners on the internal driver is selling you a product that is destined to have problems. At Hongyu Bulb, we know that silent operation isn't an accident; it's a specific engineering goal. We assume our bulbs will be used in demanding environments, so we build them to be robust and quiet from the inside out.

The Source of the Buzz: Internal Components

The main vibrating component inside an LED driver is the inductor (also called a choke). An inductor is a core wrapped in a tight coil of wire, and its job is to smooth out the electrical current. When electricity passes through it, it creates a magnetic field. Tiny fluctuations in this field can cause the inductor to physically expand and contract ever so slightly—a phenomenon called magnetostriction. If the inductor is cheaply made with loose windings or a poor-quality core, these vibrations become strong enough to produce an audible buzz.

The Hongyu Bulb Solution: Better Components and Potting

A reputable manufacturer like us tackles this problem head-on in our design and production process. It's not one single thing, but a combination of quality choices.

• Superior Component Sourcing³: We source our inductors and other critical driver components from top-tier suppliers. These components are made with better materials and tighter manufacturing tolerances, making them inherently less prone to vibration.
• Driver 'Potting'⁴: This is a critical manufacturing step that cheap suppliers always skip. "Potting" is the process of completely encasing the driver's circuit board and components in a solid block of thermally conductive epoxy resin. This does two things: First, it helps dissipate heat away from the sensitive electronics, extending the bulb's life. Second, and most importantly for this problem, it physically locks all the components in place. The solid epoxy acts as a damper, absorbing any micro-vibrations from the inductor and preventing them from becoming an audible buzz. A potted driver is the mark of a high-quality, reliable LED bulb.

When you hold a cheap bulb and one of ours, you can't see the difference on the outside. But the potted driver inside is one of the key reasons our bulbs perform silently and reliably where others fail.

Why Do My LEDs Buzz on a Regular, Non-Dimming Switch?

You're completely baffled because your LED bulbs are buzzing even though you don't have a dimmer. They are on a simple on/off switch, which should be providing clean power, but you still hear that annoying hum.

Buzzing on a standard switch is rare but possible. It can be caused by poor power quality in your building's wiring (harmonic distortion), interference from large appliances on the same circuit, or an extremely low-quality bulb driver.

This situation can be very frustrating for a buyer or installer because it seems to defy logic. If there's no dimmer chopping the power, what could be causing the vibration? The answer is that the power coming out of your wall socket might not be the pure, clean sine wave you think it is. The problem may not be the switch, but the power flowing through the switch.

Potential Causes of Non-Dimmer Buzzing

• Harmonic Distortion⁵: This is a type of electrical "pollution" within a building's wiring. It's often created by other electronic devices with switching power supplies (like computers, TVs, and motor controls). These devices can create high-frequency noise that piggybacks on the main power line, creating a distorted waveform that can cause a sensitive, low-quality LED driver to buzz.
• Interference from Large Appliances: Heavy-duty motors in appliances like refrigerators, air conditioners, and shop tools can cause significant fluctuations and electrical noise on the circuit they share. If your buzzing LED bulbs are on the same circuit as one of these a.m.pliances, the motor starting up or running can induce a hum in the bulbs.
• Incompatible "Smart" Switches⁶: Some non-dimming smart switches or timers (especially older 2-wire models) function similarly to dimmers. They may leak a small amount of current to power their Wi-Fi or timer electronics, which can be enough to make an LED driver buzz, just like a dimmer.
• Extremely Low-Quality Driver⁷: In some cases, the driver in the bulb is just so poorly designed and constructed with such loose components that even a relatively clean AC signal is enough to make it vibrate audibly.

A Simple Troubleshooting Process⁸

If you encounter buzzing on a standard switch, here’s how you can diagnose it:

This process helps you quickly determine if the fault lies with the building's wiring or with the quality of the bulb itself.

Conclusion

A buzzing LED bulb almost always points to an issue with the driver, often triggered by a dimmer. Solve this by pairing quality bulbs with modern, LED-compatible dimmers for guaranteed silent performance.