Page 63
<<• The OPTICAL 3 and 4 terminals on the AVR-3806’s rear panel
are equipped with an optical digital output terminal for
recording digital audio signals to a CD recorder, MD recorder, or
other digital audio recording deck. Use this for digital recording
between a digital audio source (stereo – 2 channel) and a digital
audio recorder.
• “PHONO” and “TUNER” cannot be selected on the “Digital In
Assign” screen.>>

I think I follow you now. You are trying to output to a recording device. Assuming your connected to optical 3 or 4 for output, what is your input?