I have a TC Electronic Desktop Konnekt 6 and I'm pretty happy with it. However, I need more inputs; 'cause I don't want to unplug-plug every instrument each time I change to instrument. This leads me it's a good idea to have a passive sound mixer for me.I looked around for a while and I loved Allen & Heath ZEDi-10. It perfectly suits me. No fx needed, just two inputs for my mics and TRS inputs for my instruments. Additionally there are 2 * DI balanced inputs for my bass and guitar, which takes away of having an external DI box I was planning to buy! It was like the best passive mixer solution for me.However; after a while, I saw Mackie BIG KNOB STUDIO PLUS. Which is an audio interface and monitor controller at the same time. I don't need an external mixer if I have this device which is far better for me. Because in fact, I don't need some features of ZEDi 10 like eq butttons, RCA outputs and so on. It's just too big. So, Mackie seems like the simplest and most compact solution for me.But, I have some doubts with it. Mainly, it's not a passive mixer, it's an active mixer. In fact, it's an audio interface which I have already.So my questions are:

1. What if I use BIG KNOB STUDIO PLUS as a mixer, with my Konnekt 6? I mean, does it effect color? If it is, how much? Do you think, is it OK to use them in this way? Or is it just ridiculous to use two audio interfaces?

2. Would you compare Konnekt 6 vs. Mackie Big Knob Studio in according to sound qualities. Would you change your audio interface in current issue? Maybe Big Knob is far better from Konnekt 6 and I have no idea about it