Since at least in theory every component in the string influences the sound... what might the Rothwells do?
There have been conflicting reports here about the Rothwells. Some people have reported finding that they compromised dynamics; others (including me, in my case with the 10 db version) have used them with fine results.
I suspect that in some of the situations in which compromised dynamics have been reported that the cause was using them to drive input impedances that were low and/or that varied significantly as a function of frequency. I don’t think that would be a problem with the Brio-r. John Atkinson measured the line-level input impedance of the similarly spec’d non-r version of the Brio as follows:
...its input impedance at 20Hz and 1kHz was, at 41k ohms, fairly close to the specified 47k ohms. Though the line input impedance dropped to 36k ohms at 20kHz, this will be inconsequential.
A concern with the Schiit Sys would be that its input impedance is only 10K, which depending on the particular source components might be too low to be optimal. Based on measurements I’ve made of the 10 db version of the Rothwell it would present the source components with an input impedance of 30K when used in conjunction with a 41K load. And that figure would most likely be higher for the 15 db and 20 db versions.
Also the Sys would require cables on its output side, which the Rothwells would not.
Regards,
-- Al