Why Do I Have Unwanted Hums and Hiss Coming from My Amp? – Help Center

Unwanted hum or hiss from BIAS Head/Rack is usually caused by grounding issues, power supply interference, or a firmware/settings problem. Work through the steps below in order.

Step 1 — Check Guitar Grounding

Mute your guitar strings with your hand. If the noise stops or reduces significantly, the issue is likely a grounding problem with your guitar, not the amp.

Step 2 — Check Your Power Supply

Try a different power outlet or a different room. If the noise disappears, the issue is with the building’s electrical supply, not your unit.

Step 3 — Use Ground Lift

If you have multiple pieces of equipment connected (mixer, audio interface, pedals), enable the Ground Lift function on the rear panel of BIAS Head/Rack to eliminate ground loop hum.

Step 4 — Factory Reset & Firmware Update

Back up your presets before resetting. Refer to How to Backup Amp Presets.

Perform a Factory Reset to restore default settings.
Update the firmware to the latest version and retest.

Still Hearing Noise?

Open a support ticket and include the following details: when and how the noise occurs, your guitar type, firmware version, and any pedals in your signal chain.