Matrix Audio X-Spdif 2

[Radoslav]

What voltage is best for external power supply for X-Spdif 2?
Specifications is DC 6-9V. But what is optimal, or is there optimal voltage?
I am talking about some good quality PSU from Keces, SBooster or UpTone audio…
There is huge discussion on PS Audio forums about this. Some says 9V is best sounding, some say 7V, other users are happy even with 5V setting, which is slightly out of nominal specs.

It would be nice to hear opinion directly from Matrix Audio.

[Tao]

The recommended voltage of external power supply for X-SPDIF2 is 6V.
The required voltage input range is 6-9V, 6V can work stably, and the higher voltage will turn into heat, so that X-SPDIF2 maybe more warmer, but if above 9V may damage the device.

[Giacomo]

I want but this converter because it let me utilize the coax input of my X sabre 3 DAC so long as I discover that it sound better than the input usb with file flac. Do you find it true?