Nos/Nib test tape (or service cassette) are special calibration cassette used by audio engineers to ensure that the tape recorder operating within standard parameters DTC-61 Dolby Test cassette With the Dolby Test Cassette type DTC-61, all cassette recorders with the Dolby Noise Reduction System can be tested and adjusted. The signal on the tape is recorded to the Dolby Norm (200 Nanoweber 400 Hz) When the DTC-61 is played on recorders with a Dolby Mark on the VU-Meter the needle should reach this mark. Should there be no mark for Dolby level on the VU-Meters, the Dolby level should be adjusted according to the manufacturer’ instructions. DMC-100 Torque meter cassette The Dmc-100 measures the torque at normal, fast forward and rewind speeds. Calibration is in gcm 0-100 The special feature of this cassette is a 5-sides display. GE-50II Speed Adjustment cassette For adjustment and control of tape speed of tape recorders with 4.75 cm/s and 9.5 cm/s. Stroboscope effect when used with a mains operated lamp. 6.3 kHz tone for head angle adjustment of the record / replay head BSC-21 Tape path mirror cassette The BSC-21 makes it quick and easy to reliably check the way the tape runs through the cassette recorder. It consist of two different tapes. Part 1 is a see-through lead-in tape for optical check-up of heads and tape guiding parts. Part 2 is a normal FE tape running for approx. 10 minutes. The FE tape has the tape thickness of a C 90 cassette. This part is used to check the way the tape runs through the recorder. BFC-41 Frequency response cassette The BFC-41 contains all reference levels needed to set up and balance cassette recorders. This covers national and international standards and manufacturers specifications. The programs are in order of test frequency and test facilities as experienced in practical use. STC-30 Stereo Test cassette The STC-30 is the ideal cassette for check hi-fi system quality Various test tones enable quick testing and reliable fault location