Hissing Problem

[mikedomi]

beavis no this is what you said and it does not say anything about the laptop
(quote)
put a 3 to 2 plug adapter on the amp. you need to eliminate the third prong on the mackie amp power cord.

the amp is not the problem it is most likely the laptop
I too had to do this to a dell all so

not taking side but I too read your post and you said nothing about it

you had the right fix just on the wrong piece