An affordable AV receiver is always a good option to consider, so Yamaha RX-S602 vs Pioneer VSX-S520 comparison definitely makes sense.
Considered AV receivers have the same number of channels 5.1. Regarding power, then RX-S602 has such a W/Ohm ratio - 80/8, 125/6 when VSX-S520 has a power of 50/4. The THD is 0.08% for the RX-S602 but 0.09% for the VSX-S520.
Characteristics of digital to analog converter (DAC) are different, Burr-Brown 384 KHz/32-bit for RX-S602 and 192 KHz/24-bit for the VSX-S520. Only the RX-S602 supports Bi-amping feature. 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-S602 has support for AirPlay, AirPlay 2, and its competitor in our comparison - AirPlay. Spotify can be used on each receiver. The RX-S602 can work with the audio stream from Deezer, TIDAL, Pandora, Napster, SiriusXM, Qobuz, and the VSX-S520 can receive a content from Deezer, TIDAL, TuneIn Radio. Compared AV receivers retain the quality of 4K/60Hz signal when transmitting from a source to a TV or projector. HDMI signal transmission in standby mode is implemented in each of the devices. The VSX-S520 can scale the input HDMI signal, unlike the RX-S602. Dolby Vision technology found support only on the VSX-S520.
Each receiver has 4/1 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. The RX-S602 supports the protection of digital content of the standard HDCP 2.3, versus HDCP 2.2 in the VSX-S520. The VSX-S520 has a built-in phono stage for connecting a vinyl player. An ECO mode is only available for the RX-S602. Both RX-S602 and VSX-S520 can be configured using the Setup assistant.
Only the VSX-S520 has a Dolby Atmos multichannel audio format support. A surround technology DTS:X is supported only by the VSX-S520.