the recording and reproducing functions can be switched over between each other using the aforementioned three control lines fig7 illustrates embodiments of rotary transformers in the rotary magnetic head type apparatus shown in fig6 the rotary transformer 28 is provided with a rotary transformer for power 7 a rotary transformer for control signals 9 rotary transformers for recorded data 251 and 252 and rotary transformers for reproduced signals 801 and 802 in the slots of the rotary transformers short rings 273 272 and 271 are inserted to reduce signal cross talk between the transformers for this purpose altogether nine such slots are provided although the rotary transformer 28 in the embodiment shown in fig7 has a planar shape it may as well be a coaxial cylinder instead fig8 illustrates rotary transformers embodied in another way in the rotary magnetic head type apparatus shown in fig6 this is an instance in which unlike the embodiment shown in fig7 the rotary transformer 28 is separated into a first rotary transformer 281 having the rotary transformer for power 7 and the rotary transformer for control signals 9 and a second rotary transformer 282 having the rotary transformers for recorded data 251 and 252 and the rotary transformers for reproduced signals 801 and 802 compared with embodiment of fig7 this embodiment permits a reduction in the number of slots per rotary transformer and the use of a rotary drum smaller in diameter for.