Mesa boogie mark IV ground

[MetalMesahead]

the switch in the back of my head has a ground A/off/B

what should i put it on

thank you :twisted:

 

[Boogiebabies]

Leave it in the middle, or neutral. I do not care if I have a little buzz, but I would rather leave the ground normally than become the ground. I have yet to find a situation where I needed to use it. If you have a ground hum, I would try a power conditioner first before switching the ground. In most cases your home AC and other electronics can cause a hum that may seem like a ground hum, but is not. Televisions and lighting drive me nuts.