After almost 5 months with my trusty starter rack 2 I never asked myself the question what these little AUDIO/DC switches do that you find on some modules like for example the 2VCA. Does this mean that the wave forms have theirs 'zero' around 2.5 volt for the Audio and for DC at 0 volt?
Also, AC coupled signals remove constant offsets so that the “middle” stays at 2.5V. So, for example, sending a slow LFO into an AC coupled input will probably cancel it and output nothing. AC is for bipolar “audio rate” signals, where you don’t want constant offsets.
DC coupled circuits just let everything through as it comes in.
So audio and CV signals will work fine through DC coupled circuits. But through AC coupled circuits only audio might work as intended.
To add another view: When you run Audio through a DC-mode VCA, it works basically, BUT: When the signal is attenuated to zero by an envelope, and the attack of the env is very short, then you will get a quick jump to around 2.5volts (the audio center) which means an audible "pop".
I started to analyse dc and ac output from 4ATTMIX with both switch settings and I could'nt find any difference. I must be missing something. Something subtle ? Plus I'm a real begginer in scoping, and I did'nt test it thoroughly, just a quick test, I will go back to it next time.
Thanks if there is any explanation that could help.