It can decode HD audio down mix to Optical out / Coaxial.
You are no need to change a new HD amp.
Very good news for Yamaha DSP-Z9 and AX2500/2600/4600 user.
Setup:
DSP-Z9, DSP-Z11.
HD100, HD8-TH
HD box setup:
HD audio pass through : OFF
Digital out : Enable
Digital signal : 5.1
Conversion:
DTS-HDMA 7.1 channel will be convert to DTS 5.1
DTS-HDMA 5.1 channel will be convert to DTS 5.1
Dolby HD 7.1 channel will be convert to Dolby EX 6.1
Not test signal:
LPCM 7.1 (I don't have this type of signal, no report)