DENON DN-820 MIC MIXING PRE-AMPLIFIER MIXER PREAMPLIFIER WORKING COSMETIC ISSUES. For sale this Denon DN-820 MIC Mixing Pre-Amplifier. For sale as pictured, no other parts or accessories are included. Just tested and this unit is in perfect working condition, but cosmetically shows some bents on the mounting ears, and marks and scratches from normal use. […]