Fix Hum and Buzz From Power Cables and Grounding
By AudioQuest | Published: 2026-10-16
Category: How-to Guides
Chase down hum and buzz in your audio system by separating power cable noise, shielding gaps, and true ground loops before you buy anything new.
Quick Answer
Most hum and buzz comes from a ground loop or a noisy component, not from the power cable itself. Before buying anything, unplug every source cable except the amp and speakers, then reconnect one at a time. If the noise returns when a specific source or TV cable is connected, fix that ground path first. Only after the system is quiet should you consider a shielded power cable or a power conditioner to lower residual RF noise.
Separate the Symptom: Hum, Buzz, or Hiss
Hum is usually a low 50/60 Hz tone tied to mains wiring or a ground loop. Buzz is a harsher, higher-frequency version of the same problem, often caused by a ground loop combined with RF interference. Hiss is different: it is broadband and usually comes from a noisy gain stage or a dirty volume pot, not from power or grounding. Listen with the volume at zero and the source paused. If the noise is still there, it is in the amp, receiver, or powered speaker. If it disappears at zero volume, it is entering earlier in the chain.
Find the Ground Loop Before You Replace Cables
A ground loop happens when two pieces of gear are grounded through different paths, and current flows between them. The classic trigger is a cable TV line grounded at the wall while the audio system is grounded through its own power outlet. Disconnect the TV coax from the set-top box or TV and see if the hum stops. If it does, you need a coax ground isolator, not a new power cable. Another common trigger is a USB DAC connected to a computer that is plugged into a different outlet circuit. Try a single power strip for the whole system as a test, then decide on a permanent fix.
Check Shielding and Cable Routing
Unshielded power cables can act as antennas and couple noise into nearby signal cables. Route power cables away from line-level RCA and 3.5mm cables, and cross them at 90 degrees if they must intersect. If you are using a stock lamp cord or a generic IEC cable on a sensitive component, a shielded power cable with a proper ground pin can reduce the RF noise that rides on the AC line. That is a real improvement, but it will not cure a ground loop. Shielding reduces what the cable picks up; it does not break a ground loop.
When a Power Conditioner Actually Helps
A power conditioner helps when the noise is coming in on the AC line from another device on the same circuit, such as a refrigerator, dimmer, or laser printer. Plug the audio system into the conditioner and plug the noisy appliance into a different outlet on a different circuit if possible. If the hum remains with only the amplifier connected to the wall, the conditioner is not the answer. It also will not fix a ground loop between two grounded components. Use it as a targeted tool, not a default purchase.
Diagnosis Checklist: Symptom, Cause, Action, Stop Point
- Symptom: Hum with volume at zero: The noise is generated inside the amplifier, receiver, or powered speaker. Disconnect all inputs and listen again. If the hum remains with no inputs connected, the fault is in the component. Service or replace it before buying cables.
- Symptom: Hum appears when a source or TV cable is connected: This is a ground loop between two grounded devices. Test by disconnecting the TV coax or the USB cable from the computer. If the hum stops, install a coax ground isolator or a USB isolator. A power cable will not fix this.
- Symptom: Buzz that changes when you move cables: The cable is picking up RF interference. Separate power and signal cables, cross at 90 degrees, and replace unshielded interconnects with a shielded design. If the buzz drops after rerouting and a shielded cable, you are done. If it persists, return to the ground-loop test.
- Symptom: Hum only when a specific appliance runs: The noise is on the AC line. Move the appliance to another circuit or plug the audio system into a power conditioner. If the conditioner removes the hum, keep it. If not, the appliance is not the source and you should stop adding power products.
What the Cable Specs Actually Tell You
- NRG-X2 Factory Certified Refurbished: NRG-X2 uses Long-Grain Copper (LGC) conductors and Semi-Solid Concentric topology, where strands are packed tightly and never change position within the bundle. Fewer strand interactions mean less self-generated distortion on the AC line, which can lower the noise floor in a system that is already grounded correctly.
- NRG-X2 Factory Certified Refurbished: NRG-X2 conductors are direction-controlled, with a marked direction for optimal performance. Installing the cable in the marked direction keeps the shielding and drain consistent with the design intent, which matters when you are chasing RF noise.
- Sydney 3.5mm Mini > RCA Factory Certified Refurbished: Sydney 3.5mm Mini > RCA uses Solid Perfect-Surface Copper+ (PSC+) conductors and Carbon-Based 3-Layer Noise-Dissipation. Solid conductors prevent strand-interaction distortion, and the multi-layer shielding keeps captured RFI from modulating the ground reference on a portable or desktop source.
- Sydney RCA > RCA: Sydney RCA > RCA also uses Solid PSC+ conductors and the same Carbon-Based 3-Layer Noise-Dissipation system. If your hum changes when you move an RCA cable, a shielded, solid-conductor interconnect can reduce the noise pickup that a ground-loop fix alone will not address.
