Hi Osborne,
I would hold tight until you receive the amp and have tried it with the 3808. The 1.2V figure given likely represents the output voltage at unity gain, or 0dB on the Denon volume control. It is VERY unlikely that the Denon will not be able to output the 1.8V required to drive the 4B to full output. The only thing you will find is that you have to have the Denon volume control at a higher setting that you are used to. If you are still using the Denon to power the other speakers in your system you will have to reduce the level settings for those channels to balance the level of your M80s.
