Use metal flathead screwdriver to Adjust Bias Potentiometer in tube amp

Thread Starter

Adam Monarch

Joined Mar 17, 2019
I am adjusting the bias settings on my Fender Tube amp and was wondering if I can use a metal flat head screwdriver to adjust the bias potentiometer or if I should use a plastic flat head screw driver. I want to make sure I don't cause more problems using a metal flat head to adjust the bias.

A metal screwdiver is fine, low voltage there and no sensitivity to a little bit of hum and noise appearing due to a metal shaft. RF and high frequency work needs a plastic tool.


Joined Jan 23, 2018
Most potentiometers will not be bothered by the use of a meal screw driver. BUT it is important to not accidentally contact any other part of the circuit while doing the adjustments. So insulating the screw driver shaft is often a wise choice.