When idling my Zkit1 build makes a low sound which I think has been aptly described as "motor-boating". Does anybody have an idea what is the likely cause of this and can you suggest any possible remedies?
The Zkit has the anniversary mods added plus two extra 47 uF caps in the power supply which helped me dial down a hum problem when I first built the amp to design. Other than that it is pretty much built to spec.

I always thought mine sounded like a helicopter.

Pretty sure its a wireless network signal getting into the amp somehow and then being amplified.

1st, turn off your wireless network source (modem) to prove that it's the culprit.  If so, figure out what you need to do to eliminate/minimize it.  Usually, repositioning the modem and/or the amp is sufficient.


Dan