Last night I used two S1s for my acoustic duo (one guitar, two vocals). I ran the guitar and vocals into my T1 mixer which was connected to input 1 on an S1 with a TRS 1/4" cable. I then ran another TRS 1/4" cable from the output of the first S1 to the second S1. I set the input volumes of each S1 at noon to control the volume from the mixer. I was surprised that the volume of the first S1 was very quiet while the second in the chain was loud. I swapped the positions of the two S1s to confirm there was no problem with the first S1. Same result. I ended up having to run the mixer volume higher and the second S1 closer to 10 o'clock on the volume to even it out.
My question is why? I know the output of the first S1 is set by the channel volumes so that is probably why, but the way it worked seemed very strange to me.