clicks/popping sound on hitmakers

Hello everyone, I built the hitmakers, unfortunately I think there might be a problem with them, I tested them after I built them on a tube amp and class A amp, then I took them to give to a friend of mine along with an smsl A100, after testing them again the sound has pops and crackling, and the amp itself makes a buzz sound ( inside the amp ), I concluded that the amp must be defective, then the next A100 had the same problems, then tried on a SML sa60 same thing. So cannot be the amps problem, anyone has any idea what the problem might be?