Abstract: A tape tension controlling circuit which eliminates a complicated controlling operation and is produced at a very low cost. A supply side tape tension regulator is provided on the supply reel side while a take-up side tape tension regulator is provided on the take-up reel side with reference to a rotary drum, and displacements of the regulators corresponding to tension values of the magnetic tape are fed back to reel controlling systems for the supply reel and the take-up reel so that the tape tension on the supply reel side and the tape tension on the take-up reel side are individually kept constant. When the magnetic tape is to be fed in a pinch-off condition wherein a pinch roller is spaced away from the magnetic tape, a take-up side tension error signal is inhibited from being supplied.

Abstract: When an MO disc cartridge 2 is inserted upside down, the leading end of a cartridge body 80 abuts against plate-like protuberances 100 provided on a tray 13 for preventing the erroneous insertion, and the cartridge body cannot be inserted further. Accordingly, erroneous insertion of the MO disc cartridge 2 can be reliably prevented. When the MO disc cartridge 2 is inserted with its upper and lower sides directed correctly, the protuberances 100 are received in respective erroneous insertion preventing grooves 86 formed in the upper surface of the cartridge body 80, thus permitting the MO disc cartridge 2 to be inserted up to the innermost position.

Abstract: A magnetic tape cassette loading system for a recording and/or reproducing apparatus, includes a cassette holder assembly for receiving and holding one cassette of any of a number of different sizes. The cassette holder assembly includes an outer cassette holder which is movable within the loading system body in the vertical and horizontal directions, and an inner cassette holder which supports a cassette therein and which is so supported on the outer cassette holder as to be movable thereon in the horizontal direction. The inner and outer cassette holders are cooperable to cause a cassette to move to an eject position, in which a cassette can be received into the cassette holder assembly and removed therefrom, and a loaded position in which cassette loading is completed.