After having
my above post #529, I noticed another highly possible confusions and misunderstandings for TRS-to-RCA cable pin assignment issue relating to Topping's pin numbering of the TRS plug found in the DM7 web site and in DM7 User Manual;
Topping says the ground pin at TRS as No.3, but it should be connected to No.1 pin of XLR connector.
Topping says the plus(+) pin at TRS as No.1, but it should be connected to No.2 pin of XLR connector.
Topping says the minus(-) pin at TRS as No.2, but it should be connected to No.3 pin of XLR connector.
In case if we would use recommended ready-made TRS-to-XLR(male) cables for amplifier's or pre-amplifier's XLR balanced input, these should
not be a problem at all, I assume, since all of the available cables are configured/connected exactly as shown in the above diagram.
In case if a naive user would like to DIY prepare his or her own TRS-to-RCA adaptor cable, however, based on the
misunderstandings of "Topping's pin number assignments are identical to the standard XLR pin numbering", then much confusions and trouble should happen.
We intensively discussed in
post #438 and thereafter that for TRS-to-RCA conversion,
"not the best but acceptable safe way would be pin No.3 floating/non-connected as Pavel of OCTO suggesting/recommending even though we lose 6 dB gain." where pin No.3 minus(-) signal means "pin No.3 in standard XLR connector configuration" which is actually pin No.2 by Topping's numbering at TRS plug!
The ground outer shield of RCA connector (always assigned to pin No.1 in standard XLR configuration) should be connected to TRS's ground (GND) which Topping says pin No.3 at TRS.
Consequently, even if we would use ready-made TRS-to-RCA adaptor or cable for DM7 with minus(-) line floating/non-connected, or if we would do DIY preparation of TRS-to-RCA adaptor cables with minus(-) line floating/non-connected, we really need to
carefully confirm the connections by a tester;
RCA outer ground shield should be connected to TRS's GND (Topping says No.3) and the RCA core plus (+) pin should be connected to the top part of TRS (Topping says pin No.1). Furthermore, TRS's minus(-) pin (Topping says No.2) should be floating, should not be connected to RCA's outer shield, should not be connected to RCA's core pin.