An active balun circuit is provided for single-ended to differential RF signal conversion with enhanced common-mode rejection which suppresses common mode signal and which achieves phase and amplitude balance without sophisticated tuning or compensation methods. The invention uses a combination of voltage and current regulation to overcome the problems encountered in the prior art. Further the ink is ejected during the actuation phase of the actuator enabling a better control of the droplet dynamics. Each of the yoke arms has a bearing bore extending between the outer face and the inner face.