Attention anyone who has been using 4CM.
The levels specified 4CM for the HD500 document that I posted here --> http://line6.com/support/docs/DOC-2522 have been changed to address recent(ish) firmware changes.
I have been aware that there was a change in the FX Send level functionality with Firmware versions after 1.40 on the HD500 and that it was no longer necessary to use a special Stereo to Mono cable (TRS to TS) to mix the FX loop down to mono. This also had an affect on the FX Send level and I have spent a little time working out what this was.
I have found
I tested this with both a Stereo-to-Mono cable and a standard guitar cable and this is the case.
Anyone who uses the 4CM setup I detail may want to take this into account for their own rigs. If you do not set the correct levels then your tone may sound weak and you will not be able to drive the amp properly.