The Onkyo TX-NR555 vs Marantz NR1504 comparison proves that these receivers have many common features.
A significant difference between the receivers in the number of channels, Onkyo TX-NR555 has 7.2 versus 5.1 for Marantz NR1504. Regarding power, then TX-NR555 has such a W/Ohm ratio - 130/6 when NR1504 has a power of 50/8, 60/6. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, Hi-Grade 384 KHz/32-bit for TX-NR555 and 192 KHz/24-bit for the NR1504. Only the TX-NR555 supports Bi-amping feature. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing. Rivals from our review have Bluetooth support. The Apple Music service is implemented on considered devices: AirPlay. Spotify can be used on each receiver. The TX-NR555 can work with the audio stream from Deezer, TIDAL, Pandora, and the NR1504 can receive a content from Pandora, SiriusXM.
Only the Onkyo TX-NR555 has support for High dynamic range (HDR). HDMI signal transmission in standby mode is implemented in each of the devices. Both competitors are not able to scale the HDMI signal. The HDR standard - Dolby Vision is not supported by these receivers.
Each receiver has 6/1 HDMI inputs/outputs. The HDMI Audio Return Channel (ARC) feature supports both devices. Unfortunately, HDMI eARC is not available on monitored devices. The Consumer Electronics Control (CEC) feature is present in most modern AV receivers and the models in our comparison are no exception. Both models support the standard HDCP 2.2. The TX-NR555 has a built-in phono stage for connecting a vinyl player. A voice control is not available. An ECO mode is only available for the TX-NR555. The setup assistant will help you configure Marantz NR1504.
Only the TX-NR555 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the TX-NR555.