An affordable AV receiver is always a good option to consider, so Marantz NR1504 vs Onkyo TX-8140 comparison definitely makes sense.
A significant difference between the receivers in the number of channels, Marantz NR1504 has 5.1 versus 2.0 for Onkyo TX-8140. Regarding power, then NR1504 has such a W/Ohm ratio - 50/8, 60/6 when TX-8140 has a power of 80/8, 110/6. The THD is the same and is 0.08%.
Characteristics of digital to analog converter (DAC) are different, 192 KHz/24-bit for NR1504 and AK4458 384 KHz/32-bit for the TX-8140. None of the models support Bi-amping. Each of the AV receivers can transmit an audio signal directly to the amplifier and bypasses any DSP processing.
Only the Onkyo TX-8140 can connect to the Internet via WI-FI. Rivals from our review have Bluetooth support. Spotify can be used on each receiver. The NR1504 can work with the audio stream from Pandora, SiriusXM, and the TX-8140 can receive a content from SiriusXM.
HDR is not available on each model. Compared AV receivers are not able to transmit a 4K signal from the source to the TV or projector. Only the NR1504 provides HDMI signal transmission in standby mode. Both competitors are not able to scale the HDMI signal. The HDR standard - Dolby Vision is not supported by these receivers. Only the NR1504 supports HDMI Audio Return Channel (ARC). Unfortunately, HDMI eARC is not available on monitored devices. Of the two receivers in our comparison, HDMI CEC is present in only the NR1504. The TX-8140 has a built-in phono stage for connecting a vinyl player. A voice control is not available. An ECO mode is not present in each of the AV receivers. Both NR1504 and TX-8140 can be configured using the Setup assistant.
None of the rivals equipped with Dolby Atmos multichannel audio decoder. The receivers do not support the surround sound technology DTS:X.