Does the Etherwave Plus allow me to control & play other synths with the CV Outs?

Yes.

• Choose either the PITCH or VOLUME antenna CV Output jacks on the bottom of the EW+, and connect a quarter inch TS cable. 
  
  
• Then connect the other end of the TS cable to the PITCH input of the external synth.
  
  
• Now connect another TS cable to the GATE OUTPUT on the bottom of the EW+, and insert the other end to the GATE INPUT of the external synth. NOTE: The gate output on the EW+ is hardwired to be controlled with the VOLUME antenna.
  
  
• Connect a TS cable from the AUDIO OUTPUT of your synth to a powered speaker. 
  
  
• You will now be able to play the synth using the EW+ as a controller!

Additional Tips:

• In order to play the synth as mentioned above, there is no need to have the AUDIO OUTPUT of the EW+ connected to speakers, however if you wanted to blend the sound of the synth and the EW+, be sure to make this connection. Dial in the mix of the two sound sources as desired.
  
  
• NOTE: The above synth control will not track 1V/OCT, but will rather perform exactly as the EW+ would. This allows you to explore many different sounds outside of the theremin’s own heterodyning oscillator, while performing in the same manner as you would normally play your EW+.