restorer-john
Grand Contributor
I have indirectly measured these in the form of elevated distortion in the sweeps. When the screw terminals in my banana plugs get even a bit loose, the wind up creating distortion due to non-linear modulation of the current going through them. I recently upgraded my locking banana plugs to a new one that allows the screws to be tightened more and this has helped a lot. The type of wire is also a factor in well you can screw things down.
By the same token, relay contacts and such can cause similar issues. We are measuring to such high precision that these things show up. Likely not an audible thing since you don't maintain high currents more or less continuously as I do in the testing. But to the extent you paid for great performance in the amp, might as well assure the rest of it is secure as well.
The meter as designed is pass-through, which is just a dumb design for speaker level indication. Parallel connection should be employed.