Will I be sacrificing much in SQ if I go with a stereo receiver vs. integrated amp. I also like to listen to music at low volumes at night (if that makes a difference).
Without opening a can of worms- will either of these amps be a considerable upgrade over my existing Yamaha AVR? And what would you recommend for my circumstances?
All four of these have quite similar performance in their amplifier sections:
Yamaha RX-A770 – 95 wpc (2 channels driven, at 8 ohms, 20 Hz - 20 kHz, 0.06% THD)
Yamaha A-S801 – 100 wpc (2 channels driven, at 8 ohms, 20 Hz - 20 kHz, 0.02% THD)
Yamaha R-N803 – 100 wpc (2 channels driven, at 8 ohms, 20 Hz - 20 kHz, 0.02% THD)
Outlaw RR2160 – 110 wpc (2 channels driven, at 8 ohms, 20 Hz - 20 kHz, 0.05% THD)
The differences between 95-110 watts per channel and total harmonic distortion of 0.02-0.06% are negligible and will not be audible, especially when listening at low volume.
None of those stereo amp/receivers should produce significantly different sound quality compared to your RX-A770. I'd keep it.