PC mixer

[soulsonic]

This Imsa guy on YouTube told me a idle, not connected to anything tl-072 consumes 2 ma.

A TL07x will typically draw less than 1mA per channel at idle, so maybe a TL072 will draw 2mA total, but this is nothing. A 12v computer supply could easily power thousands of these. And this wouldn't put a heavy draw on your virtual ground; the input bias currents are measured in picoAmps. People build FX pedals chock full of TL07x chips and power it from a single 9v battery all day long.

A TL06x will draw only 200uA per channel. You could use these strategically in low gain sections of the circuit where the poorer noise performance wouldn't be an issue. I wouldn't use them for the summing amp, but for input buffers and the like, they could be a good choice.

I'm making this mixer for breadboard audio experiments while still being able to listen to the pc (onboard audio).
Someone mentioned it would be wise to protect the summing core in some online article.

When i disconnect the jack/cable from the cheap speakers from the pc mainboard, they are completely silent, but plugged there is some humming. maybe this will help
: )

Filtering out inaudible frequencies won't help with hum one bit. And as I said, it's dead simple to design the summing amp such that it doesn't amplify any inaudible high frequencies. This is as easy as strapping a suitable capacitor across the feedback resistor. I can't imagine a situation where it would need "protected." Protected from what? High frequencies coming out of a breadboard with low voltage circuits on it won't blow anything up. The only protection you should be worried about would be to put ESD protection diodes on the inputs to keep the chips from getting zapped from static discharge.