Warning
Amplifiers utilize levels of voltage that may cause serious injury or bodily harm. If you are unfamiliar with the maintenance of tube amplifiers, we recommend seeking assistance from a trained amplifier technician.
Rattling or Buzzing Noises from Amplifier
The following are some common causes of rattling or buzzing noises from the amplifier, and items to check before bringing the amplifier to a repair technician.
Loose Screws
The most common cause of rattle/buzz in an amplifier will be loose screws. Screws may loosen up in shipping or become loose over time from vibrations of the amp in use.
This looseness causes a rattling sound to come through the amp’s speaker. Using a Phillip’s head screwdriver, check that the following screws are hand-tight:
- Check the chassis mounting screws on top of the amplifier.
- Check the auxiliary panel screws on the back of the amplifier.
Do not overtighten. The screw threads may strip, which can worsen a rattle/buzz.
Amplifier Tubes
Another common cause of rattle/buzz in an amplifier will be the vacuum tubes. Preamp or power tubes can become microphonic, which then creates a buzzing or ringing sound.
Occasionally, the vibrations of the tube will be frequency dependent and may be more noticeable with specific notes or frequencies from your guitar.
To check for microphonic tubes, a pencil eraser or chopstick may be used. Take caution when checking the tubes—they will be very hot. Gently tap on each tube with the stick one by one, listening for changes in the amplifier’s output sound.
If any tube is consistently making noise when touched with the stick or at a specific frequency, it may be time to replace that tube.
If a power tube is identified as the culprit, be sure to replace all power tubes with a new manufacturer-matched set.
Internal Speaker
Other unwanted noises can occasionally originate from the internal speaker. To confirm if the internal speaker is the cause of the noise, try to run the amplifier through an external speaker cabinet (if available).
For a visual guide on the steps outlined above, you can find our video on the subject here: Identifying Rattles & Buzzes In Your Amplifier | Customer Service | PRS Guitars
If noise issues persist, please contact the PRS Customer Service team for further assistance.