Having had an opportunity to test Onkyo TX-RZ820 vs Marantz SR5012, I’d like to share my impression here to facilitate your choice of a new AV receiver.
AV receivers under review have the same number of channels. In terms of power, there are differences, the TX-RZ820 has such a ratio W/Ohm - 160/8, while the SR5012 has a power of 100/8. A common feature for devices is the same total harmonic distortion - 0.08%.
The manufacturer installed different DACs, the TX-RZ820 received the model AK4458 384 KHz/32-bit, but the SR5012 is equipped with 192 KHz/24-bit. Each of the compared opponents supports Bi-amping. Both Onkyo TX-RZ820 and Marantz SR5012 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-RZ820 works with Deezer, TIDAL, but the Marantz SR5012 works with Deezer, TIDAL, Pandora, Napster, SiriusXM, TuneIn Radio, iHeart Radio, Sound Cloud. 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-RZ820 and the SR5012. Video scaling is only possible with the SR5012. Each of the participants of the comparison has a Dolby Vision.
The number of HDMI inputs/outputs varies depending on the receiver, the TX-RZ820 has 7/2, and the SR5012 has 8/2. HDMI Audio Return Channel is implemented in both devices. HDMI eARC is not supported by the TX-RZ820 and the SR5012. When comparing receivers, it becomes clear that each of the rivals can work with HDMI CEC. TX-RZ820 and SR5012 support the standard HDCP 2.2. In the presence of a built-in phono stage for connecting a vinyl player only at Onkyo TX-RZ820.
Ability to create 2 Multi zones inherent in both AV receivers. There is an ECO mode in either AV receiver. The Onkyo TX-RZ820 and the Marantz SR5012 can be properly configured using the setup assistant.
A Dolby Atmos multichannel audio format is available both models. A DTS:X surround technology is supported by devices from our comparison.