I've recently gotten a 751r, having read through all the helpful posts in this thread. As everyone says, it's a bit of a cantankerous beast, but it's all worth it for the sound quality! I have a couple of questions I thought you guys may have come across:
a) I have a HDMI feed (audio + video) into the receiver, and HDMI output to my Samsung smart tv. Sometimes I use the TV to browse my media, and then want to turn it off to just listen to music. When I turn off the TV it actually interrupts the music for 5 or so seconds and then re-locks onto it. Why would removing an *output* affect how the receiver gets its input? The PCM stream (PCM 2/0) stays the same after re-locking; though I do find the PC volume mixer no longer applies (as I found out in one eardrum-popping discovery, going from 15% output to 100% after the TV turned off! Still recovering from that one...)
If I then turn the TV back on, the music interrupts again and doesn't return unless I go to the PC, stop playback and start again. So some kind of syncing issue perhaps? Or it's changing to bitstream or WASAPI or something?
b) In speaker settings, I set subwoofer to 'yes' and L/R to 'small'. If I toggle stereo mode to no longer use the subwoofer, does it automatically set the L/R speakers to 'large'? Going back into the OSD it still just says sub yes, speakers small. It sounds bassy enough to my ears, but atm I'm leaving speakers on 'large' in any case and I haven't observed any issues.