Just to round this topic off, I have my 218 working the Harmony using a G12.

I was unsuccessful in getting the 218 to work with any other 3 wire 12 volt receiver.

Interpreting the Technote, it appears that 3rd party receivers or direct connection will not work with firmware build 185.

There is currently no build later than that and I believe is not planned in the near term


861v8+ID41 Revelation One filter, HD621, Musical Fidelity M8 700 mono blocks, Focal Scala (x2), Focal Mini Utopia (x3), Velodyne DD18, Oppo BD105, Roon NUC, 218, Radiance 2021, JVC X9000