amplifier riddle

[vibrating string]

We had a letter from the water company saying that they need to change out my old water meter with a new one. The meter was behind a wall, so I had to break down some sheet rock to expose the meter. The technician came and made the change yesterday, but he said something to me that made me think to run up to my recently rebuilt Ampeg GuitarAmp and turn it on. So after he left, I did this and the amp sounded better. Why?

I will follow with the answer in a few days. Maybe no one will see this, but I think it is an interesting result. Others may have a similar issue and will benefit knowing the answer.

Larry