Nakamichi 481 Service Manual - page 9
Manual is about: Diskrete head cassette deck
of
66
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It is specified in the IEC Standard that the time constant is
120 us on tapes of ferric oxide, and 70 us on tapes of
Cr02.
However, in the case of Eq. Switch on N-481, when time
constant at playback is changed, at the same time
constant at record must also be changed. Therefore,
even though record and playback is made by the method
other
than the IEC Standard, no deterioration of frequency
response or level difference will occur. (Any other method
for instance, record and playback on ferric oxide tape with
putting Tape Switch on EX and Eq. Switch on at 70 us.)
When Nakamichi EX or EXII Tape is used at Tape Switch:
EX, and Eq. Switch: 70us, S/N ratio will be improved by
approximately 4 dB (WTD).