Beware when buying second hand headsets. I bought a second hand david clarke H10 30 from an instructor who was moving on to pastures new. I thought it would be good to have a spare pair.
I dont know exactly whats wrong with them but all is well until you get some engine power on then you get horendous noise and distortion which stops you being able to talk to ATC, this is true even if a pasenger is wearing them.
needless to say, the person I purchased them from is no where to be found, I wish I had paid a bit more and got new instead.
Incedentally the instructor was from america, so I guess was the headset, could that be the problem?