For RCA, all you need is a pair of cheap adapters or a cable.
https://www.amazon.com/WOVTE-Stereo...=1561960006&s=gateway&sprefix=jack+rc&sr=8-16
For what I can see, there is also no tone control and no remote control support.
But that's still 2/3 the price... and less than half the price of the Pro.
By the way, the headphone Amp, if I understand it correctly, may work fully in analog domain
RME claims ADI-2 fs has the same DAC chips and analog circuitry as the DAC/PRO onboard, therefore same performance up to 192K.
It also includes an ADC, like the PRO, w similar performance promise.
I had ordered one in march, though latest delivery word from them is September (this year!)...anyway I don´t need no mickey mouse displays, tone controls or alterable filters, just hoping for the promised performance. Cables to hook up to the stereo are ready since easter, as well as a linear regulated PS!
- A later test by Amir would be really helpful to see whether its performance is really comparable to the DAC/PRO versions!!!
One late remark regarding missing USB:
I am using 2 boxes w C-Media chips (50bucks each) in both SPDIF/USB directions, they seem to behave bit-perfect up to 24bits, no sound issues.