Hi – I have a question about an aux switch for the H9.  If I just want one for the tuner will a one-button aux switch work?   I've seen it mentioned that you need a 3-button switch but I'm assuming that's for activating other functions as well.  I'm just looking for simpler access to the tuner.  Thanks.

If you just want it to activate the Tuner, a one button switch will be fine. (Make it momentary).

This allows you to use an expression pedal as well if you want (with a little fiddling).