Don- That setup does not buzz when the cables are tightened?
Just a tiny bit?
On 6V I can get it all to zero noise -but simply a light tug on a cable will start the slow buzz and ditto on ganged aileron servos -a slow grumble /buzz from the weight of the ailerons - the mechanical linkage can be spot on but these things seem to read any error or work load -even tiny ones from a little finger pressure .
They do work extremely well - I just can't perfectly stop the slow, low noise on ganged setups