I just completed the build of a PAU Sukhoi. Part of that build was the installation of MKS 777A+ servos on all the control surfaces. Upon completion of the installation I noticed a slight flutter in the elevator servos particularly when I switched from high rates to low rates or if I moved the trx sticks rapidly. After consultation with the techie at MKS he advised that the problem was caused by poor quality servo extensions even though the extensions used were heavy gauge. The issue is not the gauge of the wire, rather the alloy of the steel contained therein. This becomes increasingly important as the extensions get longer such as elevator servos in the tail of the plane. Today’s high frame rate high speed servos require a very clean signal, especially when Spektrum Power Safe receivers are in use. Additionally, Spektrum recommends that signal boosters not be used. MKS recommend the use of a superior quality servo extensions such as the ones offered by Power Box systems. I ordered them from Horizon (available also from Chief Aircraft), installed them on the elevator servos and the servo flutter problem went away. I am now in the process of replacing the wing servo extensions with Power Box (German made) extensions.