PURPOSE: To increase the lifetime of an electric-mechanical transducer, by exercising control to minimize the DC voltage component of a switch timing signal of a reference signal when the driving voltage is applied to said trasducer which gives a displacement to a record track.

CONSTITUTION: Magnetic heads 40 and 41 are attached to electric-mechanic transducers 42 and 43 respecrively and revolved by a DC motor 47 together with revolving phase detecting magnets 44 and 45 in one body with a rotary disk 46. A revolving phase detector 48 is set in correspondence with magnets 44 and 45. A magnetic tape 52 is driven by a capstan 53 and a pinch roller 54. The driving voltage is mixed by an MIX circuit 36 between transducers 42 and 43, and the DC voltage component is extracted through an LPF46. A pseudo control signal generating circuit 65 varies the ratio of the output of a capstan FG amplifier 61 in response to the DC voltage component. The output of the circuit 65 is controlled to switch the oscillation frequency of a reference signal generating circuit 66 to minimize the DC voltage component which is applied to the transducers 42 and 43. This prevents the deterioration of sensitivity and therefore increases the lifetime of the transducers 42 and 43 respectively.