Having had an opportunity to test Onkyo TX-NR555 vs Yamaha RX-S602, I’d like to share my impression here to facilitate your choice of a new AV receiver.
The number of channels for receivers is different - 7.2 versus 5.1, respectively, for devices. In terms of power, there are differences, the TX-NR555 has such a ratio W/Ohm - 130/6, while the RX-S602 has a power of 80/8, 125/6. A common feature for devices is the same total harmonic distortion - 0.08%.
The manufacturer installed different DACs, the TX-NR555 received the model Hi-Grade 384 KHz/32-bit, but the RX-S602 is equipped with Burr-Brown 384 KHz/32-bit. Each of the compared opponents supports Bi-amping. Both Onkyo TX-NR555 and Yamaha RX-S602 can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
These units have the same Wi-Fi modules. Each of the receivers has a Bluetooth connector. The contenders have differences in the supported services from Apple - AirPlay versus AirPlay, AirPlay 2 respectively. Access to the Spotify service is on each of the competitors. The number of available streaming services varies for receivers, the Onkyo TX-NR555 works with Deezer, TIDAL, Pandora, but the Yamaha RX-S602 works with Deezer, TIDAL, Pandora, Napster, SiriusXM, Qobuz. The quality of 4K/60Hz signal remains unchanged when transmitting from a source to a TV or projector via HDMI for both receivers. Signaling over HDMI in standby mode can provide the TX-NR555 and the RX-S602. None of the devices can increase the resolution of the incoming video signal. Review participants do not have the Dolby Vision feature.
The number of HDMI inputs/outputs varies depending on the receiver, the TX-NR555 has 6/1, and the RX-S602 has 4/1. HDMI Audio Return Channel is implemented in both devices. HDMI eARC is not supported by the TX-NR555 and the RX-S602. When comparing receivers, it becomes clear that each of the rivals can work with HDMI CEC. The TX-NR555 has support for the standard HDCP 2.2, compared to the RX-S602, which supports the standard HDCP 2.3. In the presence of a built-in phono stage for connecting a vinyl player only at Onkyo TX-NR555.
Ability to create 2 Multi zones inherent in both AV receivers. There is an ECO mode in either AV receiver. The Yamaha RX-S602 can be properly configured using the setup assistant.
A Dolby Atmos multichannel audio format is available only in the TX-NR555. Only in the TX-NR555 realized a DTS:X surround technology.