This is a measurement and review of the Schiit Sys switcher and passive pre-amp. It retails for just $49 plus shipping which is reasonable. The unit is on loan from a member so not new.I will do a teardown later but for now, there are just two inputs, one output, and a volume control in there. No other passive or active components.Let's start with frequency response at different volume control settings:Frequency response is essentially rule flat to 30 Khz which is nice.Channel matching starts with a small deviation and grows to 0.5 db at 12:00 o'clock volume setting. Lowering the volume to 3:00 o'clock increases this error to 1.3 dB. So probably not a good idea to use it below 12:00 position.Phase measurement between channels is boring and inconsequential:Let's look at channel separation:Bottom two lines are without Sys in the loop. Once we insert Sys in the path, we lose about 5 to 15 db of that. It sounds like a big number but the overall levels are still very good, ranging from -100 db to -125. You would expect some drop due to more cables, switches, etc. Not an audible concern.Perhaps the most interesting measurement is the impact on THD+Noise at different volume levels:At full volume Schiit Sys is transparent. As we lower the level on Sys, naturally the measurement noise as a percentage rises leading to the graphs that you see. In other words you lose signal to noise ratio with passive volume controls.The rise in distortion at high levels though is a bit puzzling (tilt up to the right). The output impedance of Sys varies with volume changes so perhaps that is interacting with analyzer input resulting in higher distortion.Finally let's look at bleed-through from one input to another:We have 70 db of separation between inputs at low frequencies, lowering to -55 dB/-60 dB at higher frequencies depending on what channel you look at. Using a 2 volt (RMS) tone generated by my analyzer at 1 Khz, I could hear the tone from the un-selected input at max volume of my Stax headphone. So probably best to mute the channel you are not using.For $49, the Schiit Sys is a bargain. I know I can't build and sell it as cheaply to you.Measurements are fine. Nothing jumps out out of ordinary. If you need a passive volume control with dual inputs, I recommend this product.Edit: See the hardware tear down here: https://www.audiosciencereview.com/...schiit-sys-passive-pre-amp-and-switcher.2338/