There are dual-knob coaxial setups that are only slightly bigger than a single knob as well. I've seen them mainly used in a course and fine adjustment setup, but you could certainly use them as atten+offset.
replyThe attenuator-inverter is super handy too. A gain knob that goes from -1 to +1 X.
replyThat's a neat trick. Only way I can think of to do it involves two op amp buffers, one inverting one not and take the signal from the wiper.
replyTotally. Also, an attenuator is easier and cheaper to implement, because it just requires normalizing V+ into the jack plug. An offset requires an adder.
replyMy preference is: attenuator < offset < attenuator + offset. I see no benefit of having to remove the knob to get to the jack as proposed in the article.
The benefit is saving space. Imagine a 10x10 grid of such jack / knob inputs.
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