After looking around and by evidence of a friend I came across this DAC and pulled out a few independent reviews and test reports on rate which ultimately convinced me to order this DAC.
The device has two digital, selectable by switch Inputs: 1x SPDIF COAX and 1x.
Since my two audio sources have only SPDIF, I still have a SPDIFCOAX converters Deleycon ordered, which is also absolutely without hesitation giving good service.
The headphone amplifier has sufficient power, I need at my DT990Pro but already as 70-80% if I'd like to hear it loud. However, the DT990Pro with their 250 ohm impedance at the upper end of the manufacturer's recommended impedance for headphones for this DAC.
Only for people who are looking for a DAC with USB interface for direct connection to a PC, are not happy with this DAC because it does not offer such a feature.
The device having an excellent workmanship and I am absolutely satisfied. For a price of about 60 euros including shipping you can not go wrong in my opinion.