Below are some S/N specs. from a ~ 1986 Yamaha AX-900U power amplifier. What is the difference in measurement setup for the "IHF-A " versus the "New IHF"? I'm only interested in the "CD etc" results. It looks like the "signal level" is not mentioned for the CD results. Does that mean the signal level is for the "rated output" conditions? (130W rms / 8 ohms)? These are 1986 specifications. Have amplifier specifications/IHF recommendations changed since then to a "newer" IHF specification?