Yah! I just tested it (it had been a while) and plugged a Volca Keys, Volca Sample, PO12 and PO16 into it. The volume drops slightly with each device plugged in, but it’s still plenty loud.
No artifacts that I could hear. Plenty clean. Had them playing at the same time. Obviously it gets a bit crowded and there’s no way to EQ anything. The interesting thing is that each audio jack on it can send or receive sound. Definitely a nifty little tool. I ended up finding one on clearance for $5 at a department store at the mall.