Yeah, the power for the overlays comes out of that box, it's like a ballast you see on fluorescent lights. So they hummm or buzz.
I notice on mine, when it's on blue and turned up it really makes a high pitched whine, which I normally don't hear anyway, but it's there. However, on green, it's virtually silent.
Either way I don't mind it at all.
About your needels, keep you eyes on them. Once you get them working, they shouldn't present any more problems.
