Hi, ekimg,
I use a Schiit Audio SYS with my desktop stereo (Audioengine N22 amp with two passive A2+ speakers) to switch between two sources and it works well. But it’s not exactly a high end system.
I also use a SYS as a switch and volume attenuator for a DVD player and third turntable phono preamp feeding a tubed preamp in my main stereo system. The preamp has four inputs but I needed five so the SYS fit the bill. The nice thing about the volume control on the SYS is that the DVD player and phono stage have very different output levels and I can attenuate the DVD player so the signal level is in the optimum range for the preamp’s input sensitivity. I use inline attenuators for a DAC feeding the preamp for the same reason. If there’s any degradation of sound using the SYS it’s not apparent, at least not to me or my wife.
The one thing you might want to consider (and Al may be able to chime in here) is that the SYS has a fairly high output impedance (5k ohms max) so if your tubed integrated amp has a relatively low input impedance you might hear a slight distortion of sound at the audible frequency extremes. The tubed preamp I have has a 220k ohms input impedance so it’s not a problem.
My hunch is that you won’t be able to hear a difference in sound quality using the SYS and you’ll appreciate being able to attenuate signal levels as needed between the two sources.
Regards,
Tom