You are able to use a second soundcard for cue channel output.
Click on the Ots Labs Power Amplifier in the OtsTurntables window. This will open the Output Configuration dialog box.
Make sure that your main soundcard is selected in the "ON-AIR" output device and that the Enabled option is selected.
Click on Set next to the "CUE" output device section to select your second soundcard.
Select your second soundcard drivers and click on OK.
Make sure that the Enabled option for the "CUE" output device is selected.
Close the Output configuration dialog box.
To test, play a file and click the Cue button on the Mixer. You should notice the cue channel output through the second soundcard.
Note: If you have received the "Failed to allocate audio device. Close other audio programs and start again" error message, this could be because you are trying to enable the same soundcard in the both the "ON-AIR" and "CUE" output options. You can not allocate the same device in both places.
Tip: You may notice the ON-AIR signal through the cue channel. For instructions on how to remove the "ON-AIR" signal from the cue channel click here.
Cue channel output options
How to remove "ON-AIR" signal from the cue channel
Adjusting cue channel levels
How to set up your soundcard (main channel)
Output Configuration dialog box