ABEX Test Tape TCC-184B, 12.5k/1k/63Hz For Azimuth & Freq Resp

Description

ABEX Frequency Response Test Tape TCC-
184B
Signal: 12.5k/1k/63Hz, -24dB (ref level: 0dB=250nWb/m, shown as -20dB on 160nWb/m players),
full track, 120us (normal position)
Duration:
1
0min
Purpose
:
azimuth adjustment
, level & frequency response check
See last picture for signal details.
Do NOT set Dobly NR ON when using any frequency response tapes.
Only use with Dolby NR OFF.
The tape is in new condition, protection case may have scratches.
About IEC-1981(Prague) standard
Earlier than 1981, there is the DIN standard which was developed by German in 1975. Before 1975, both BASF in Germany and Japan produced produced test tapes. TEAC started MTT series as early as 1968. But the standard by DIN in 1975 was not noticed by Japan and this caused a different in reference levels in different frequencies. The difference resulted in sound quality and was noticed by Cughs Mkengie. Later BASF and TEAC investigated the cause of the difference in 1977 and after almost two years they found the cause. In 1979 on conference IEC SC-60A BASF reported the progress of the work and in 1980 Germany and Japan agreed on the new characteristics. In 1981 IEC SC-60A Prague conference, a report concludes:
In the past, due to lack of cooperation and communication in countries, test tapes produced are not on the same standard. Even around 1980, the difference was not resolved.
BASF and TEAC agreed on a new way to produced test tapes upon: a) new method of measuring magnetic: at 315 Hz, 0dB is 250nWb/m b) the method to measure frequency characteristics with standard playback head c) fix the curve of previous frequency response, but not make the change too big.
The new frequency response characteristics curves published on the conference are called  the new IEC-1981 (Prague) standard.