What happens if an insufficient ground is measured under load in an amplifier?

When an insufficient ground is measured under load in an amplifier, there is likely to be a difference of potential between the negative battery post and the negative input of the amplifier. This scenario occurs because the grounded connections that typically lead back to the negative terminal of the battery may not be effective due to poor connections or inadequate wire gauge.

Under load, the amplifier demands current, and if the ground connection is not solid, it can create voltage drops across the ground path. This results in a situation where the negative terminal of the amplifier does not sit at the same potential as the negative battery terminal, leading to undesirable conditions such as noise, distortion, or even amplifier shut down due to improper operation. Hence, measuring a difference of potential in this way is a clear signal that the ground connection is insufficient and needs to be addressed to ensure the amplifier operates correctly.