Control Voltage is the voltage used to control an analog circuit, like VCA’s, VCO’s all that kind of synthesizer stuff.

Note that DC coupled means there are no capacitors in the audio path of the circuit. Just because a device is DC Coupled does not automatically mean it will pass DC content. This is because there are many active ways of removing DC content. The AD16x and DA16x for instance are entirely DC coupled. But neither of them will pass DC.
The following Apogee products will pass DC to the analog output for Control Voltage:
  • Symphony I/O MkII – All modules
  • Original Symphony I/O – All modules

That’s it as of 7/1/2019

Note that the Symphony module cards are DC Coupled AND pass DC for Control Voltage on the analog outputs.