Yamaha RX-V685BL vs Yamaha RX-V4A comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Yamaha RX-V685BL has 7.2 versus 5.2 for Yamaha RX-V4A. Regarding power, then RX-V685BL has such a W/Ohm ratio - 90/8, 150/4 when RX-V4A has a power of 80/6. The THD is the same and is 0.06%. Both the RX-V685BL and the RX-V4A support Bi-amping. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
WI-FI modules have the same characteristics: 2.4/5GHz. Rivals from our review have Bluetooth support. The Yamaha RX-V685BL has support for AirPlay, and its competitor in our comparison - AirPlay, AirPlay 2. Only the RX-V4A supports Spotify.
Both AV receivers support HDR10 technology (High dynamic range). HDMI signal transmission in standby mode is implemented in each of the devices. Both rivals can scale the resolution of the incoming HDMI signal. The HDR standard - Dolby Vision is supported by these receivers.
The Yamaha RX-V685BL has 5/2 HDMI inputs/outputs versus 4/1 HDMI connectors of the Yamaha RX-V4A. The HDMI Audio Return Channel (ARC) feature supports both devices. HDMI eARC is available in each model. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. The RX-V685BL supports the protection of digital content of the standard HDCP 2.2, versus HDCP 2.3 in the RX-V4A. The RX-V685BL has a built-in phono stage for connecting a vinyl player. It is also worth noting that the ECO mode is presented in each of the receivers. Both RX-V685BL and RX-V4A can be configured using the Setup assistant.
Only the RX-V685BL has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the RX-V685BL.