CV output has long topped many people’s ER-301 wish list. But how to sneak a DC voltage past the AC-coupled outputs?
The classic method:
Attenuate some noise such that the amplitude is equivalent to your desired DC voltage, then extract that voltage using an envelope follower. And as I confirmed last night, such a method works just as well on the ER-301 as it does elsewhere.
My completely unnecessary method:
As above, but mult the resulting DC voltage back into the ER-301. Take that voltage and compare it to your setpoint. Consider the difference between these as “error”. Feed the error into three mixer channels which act as proportional, integral (low-pass filter as integrator), and derivative (microdelayed error comparison to extract slope) terms. Use this as your control signal over the attenuation of your noise.
This resulted in a hilarious, poorly-tuned, ringing mess of a control voltage. Much “worse” than the classic method, but somehow much more fun. And that is probably the end of my “janky ER-302” story since I greatly prefer its neighboring Teletype for CV duties