Retro Audio: A Good Service Guide roller. The play heads could be described as electromagnets and the magnetic tape as
Figure 7-1 The audio compact cassette having multitudes of recorded imprinted magnetic particles. Further description of play heads is provided later in this chapter.
ERASE HEAD
REPLAY HEAD
RECORD HEAD
CAPSTAN
PINCH WHEEL
Figure 7-2 The audio compact cassette tape path The pressure pad applies gentle pressure on the magnetic tape to the tape head allowing good contact as it passes from the supply reel to the take up reel via the guide rollers. This pad is essential for high frequency response at slow cassette speeds. However, the pad must not be too tight to create tape damage. A magnetic shield is found in most good quality tape cassettes. In the earlier days of cassette technology, players and recorders utilised high impedance heads. Due to this, the head is susceptible to noises from stray electromagnetic fields. Changing technology allowed for modern heads to have lower impedances and being relatively immune to stray fields of the era. The shield is maintained in order to be compatible with older cassette machines. The shield material is made from non-magnetic material with good permeability to draw the stray magnetic fields away from the head. Slip sheets play an important role in wow and flutter levels of a moving tape. These sheets act as bearing surfaces for the hubs and as gentle guides for tape packs. They provide uniform tape travel and ultimately reduce tape edge damage.
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